Synthetic Oil or Regular Oil and which brands?

[jack65]

Should I use Synthetic Oil or regular oil in my Ram truck.
Which brands do you suggest?

How often to change the oil in 2014 Ram 5.7 Hemi? It's just a tad under 50K miles now. I drive less than 5K miles a year on it. I tow a trailer maybe 4-6 times a year. I was thinking 8,000 miles or 6 months, whichever comes first.

[Frank G]

What does the book say to do? Believe it or not Walmart's Super-Tech oils get high ratings when compared to popular brands. Reference literature published on Geno's Garage Website. This is a hot button topic! :popcorn::popcorn::popcorn: Synthetic for sure, Amsoil if you have the cash. A better filter is more important. There are volumes published on the subject with testing data, some rigged, some fair, you just have to sort it out. Oil testing is a smart thing to do.

[Dave W]

Does Ram recommend a specific, easily accessed brand? If so, that's probably the best, Ford has their Motorcraft and for a gas engine I used their semi synthethic, For the diesel, their Diesel Blend. Whatever national grand that is easily found at any NAPA, Walmart, Tractor Supply or whatever and meets the specs in the owner's manual is as good or better then the often hard to find niche names such as Lucas, Royal Triton or (apologoes to the poster above) ) Amsoil and a bunch less expensive

[66joej]

For gassers I have been using Mobil1 synthetic oil and filter for years. I go by the maintenance guide in the owner's manual if still under warranty. Document with purchase receipts. After that 2 times a year depending on mileage and use. Lots of towing more frequently. Some of the newer vehicles have extremely long service intervals. YMMV

[jkohler70]

I read once that synthetic blends are a waste of money. There's no regulation on what constitutes a synthetic blend or semi-synthetic. Is it 80/20? 50/50? Only the manufacturer knows and they aren't telling.

[flybouy]

I would suggest checking out some forums dedicated to Ram trucks. I think you would get a wider readership and larger response numbers. One thing I would strongly urge you to do is to consider a quality oil filter, not a Fram. I only use Motorcraft filters and oil based on the overwhelming response on the deisel forums. YMMV

[sourdough]

I used to believe in oil changes every 3000 miles using regular oil (decades ago). Vehicles would still use a little oil (all bought new) over time and the oil would get dark brown. Started using synthetic, Mobil 1, and premium oil filters and change every 5k. I've not had an engine use oil or get dark brown since. I'm a true believer in the synthetic - I used to think it was a gimmick when it came out but no longer. I will say the first time I used synthetic was on a vehicle that had several thousand miles on it and had been ran with regular oil. When I switched to synthetic on that engine it used more oil if I recall....but that was a long time ago.

[KCSA75]

I've been using Valvoline in all my vehicles since I was a teenager and I agree that a quality filter is key.

Unless you're owners manual or Dodge dealer tells you otherwise, I would use a sythentic oil. Even if you don't drive it it a lot, dino breaks down over time. Synthetics break down too, but not nearly as fast.

[travelin texans]

There are 3 very good answers to this & has been going since synthetics came on the market;
#1 Yes, always!
#2 No way, too expensive!
#3 Maybe, can't hurt!
All of these will be discussed here!
Most all newer vehicles recommend synthetics, or blends, mostly due to the growing number of tree huggers that oppose fossil fuels, which is ok, but!
Also newer vehicles have much higher mileage change intervals, good or bad, but as mentioned l haven't had a vehicle that used oil in years, gas or diesel engines.
As far as oil turning dark, a diesel will be clear when changed til about the mileage of driving home from the oil change & the synthetic will be the same. Had a garage tell me my diesel needed an engine flush cause the oil was black, I told them it was a diesel & in 7500 miles if it wasn't black something else was wrong.
If you read your manual, mine said something to the effect that regardless of oil used it does not increase oil change intervals.
I've used all 3, dino, full & blended synthetics, in gas & diesel engines & personally noticed no difference in performance, mileage or engine longevity between 1 or the other.
It boils down to the same question, "which truck would you buy?", it's your money so use what you want or better yet what the manufacturer recommends.

[jack65]

For gassers I have been using Mobil 1 synthetic oil and filter for years. I go by the maintenance guide in the owner's manual if still under warranty. Document with purchase receipts. After that 2 times a year depending on mileage and use. Lots of towing more frequently. Some of the newer vehicles have extremely long service intervals. YMMV

I was mostly curious to what you guys were running on your rigs.
What my manual says is attached screenshots.
I ran Mobil 1 synthetic oil in my high performance Corvette for years.
I usually go by what my mechanic of 20 years tells me... he has never failed me yet. Him and his son, grandkids all have Ford/Ram pickups.
So, I'll ask him what he is running next time I see him. According to my gauge sensor says I'm 78% good at only 1,558 miles on last oil change. Pic attached.

I just got this pickup three months ago and only put 1,558 miles on it so far, so when the six months is up, I'll change the oil.

BTW, I was quite shocked:eek::eek: to see that the tranny oil was never to be changed and no dipstick either for a 8 speed tranny. 120K if you have a 6 speed.

[gearhead]

In any kind of severe service...towing, extreme temps, and short duration trips I would definitely recommend a synthetic. I run it in everything from lawnmowers, generators and vehicles. Small engines have a tendency to shear conventional oil.
Yes there is a difference of opinion on what a real synthetic is. There are different classes of the base oils. Amsoil and Royal Purple are real synthetics...PAO..Poly Alpha Olefins. They are expensive and are designed for long duration oil changes. Longer than your car manufacturer recommends.
I use Shell products mostly because I worked for them for 40 years, retiring as a Machinery Specialist. I run T6 Rotella 5W-40 synthetic in the diesel tuck and the small engines. The wife just bought a new Chevy Traverse and I will run Pennzoil 5W-30 synthetic in it. That has base oil from the Shell Quatar Pearl natural gas to liquids plant.
Good reading: bobistheoilguy.com
I tend to use OEM filters except a Fleetguard for the Ram diesel. Definitely don't use the "orange" Fram. If not OEM, maybe WIX.

[gearhead]

Dive off into this when you have a clear mind:
https://www.bobistheoilguy.com/

[Frank G]

My late brother and I had a string of vehicles in the 70's,80's,90's and 00's that we ran Amsoil and filters. We adhered to the 1year or 24,000 mi change interval and never had a issue. Some had over 200K before trading. Even used it in the 460 F350 CC DRW pulling the 6 horse steel trailer. It is good oil.

[Freeheel4life]

I was mostly curious to what you guys were running on your rigs.
What my manual says is attached screenshots.
I ran Mobil 1 synthetic oil in my high performance Corvette for years.
I usually go by what my mechanic of 20 years tells me... he has never failed me yet. Him and his son, grandkids all have Ford/Ram pickups.
So, I'll ask him what he is running next time I see him. According to my gauge sensor says I'm 78% good at only 1,558 miles on last oil change. Pic attached.

I just got this pickup three months ago and only put 1,558 miles on it so far, so when the six months is up, I'll change the oil.

BTW, I was quite shocked:eek::eek: to see that the tranny oil was never to be changed and no dipstick either for a 8 speed tranny. 120K if you have a 6 speed.

I'm not sure about Ram but other cars I've worked on the percentage of oil isnt just a true mileage %. ECM looks at idle time, duty cycle, short term fuel trims etc to decide that % of oil life left. Whether some of that's a tactic to get you back into the stealership for an oil change or is simply fact could I'm sure be argued up and down.
I think a lot depends on OEM. When I was wrenching on snowcats with Mercedes 906LA diesels the manual from Mercedes state you could run a conventional for 200 hours, a synth blend for 400 or 600 hours(can't remember which), and a full synth was good for 800 hours. So obviously MB thinks a full synthetic is able to stand up to longer duty cycles, for whatever that is worth.

[66joej]

I was mostly curious to what you guys were running on your rigs.
What my manual says is attached screenshots.
I ran Mobil 1 synthetic oil in my high performance Corvette for years.
I usually go by what my mechanic of 20 years tells me... he has never failed me yet. Him and his son, grandkids all have Ford/Ram pickups.
So, I'll ask him what he is running next time I see him. According to my gauge sensor says I'm 78% good at only 1,558 miles on last oil change. Pic attached.

I just got this pickup three months ago and only put 1,558 miles on it so far, so when the six months is up, I'll change the oil.

BTW, I was quite shocked:eek::eek: to see that the tranny oil was never to be changed and no dipstick either for a 8 speed tranny. 120K if you have a 6 speed.

I had a 2013 Ram 1500 5.7/8 spd and never really believed the oil life remaining gauge. Go by severity of use and mileage.
The Fiat 8 speed trans is a lubed for life unit. Guess it doesn't matter if it's a grocery getter or a TT hauler. Frankly I had mine changed at the dealer at 80kms (50k mi). SM questioned my reasoning told him if clutch packs are engaging/disengaging I didn't think oil will not heat up and break down.
I'm an old mechanic from the 50s so I guess I might not be up to today's technology. YMMV

[busterbrown]

If you have the patience and time, there's ONLY 2279 pages of synthetic oil and brand discussion over on the RAM owners forum (https://www.ramforum.com/threads/synthetic-oil.27664/). It's mind numbing after about 20 pages! LOL

For me though, I just stick with a good quality synthetic that FCA recommends (or is in bed with! ;) ) Pennzoil Ultra Platinum. I don't want a claim denied for powertrain issues prior to the expiration date of my manufacturer's warranty.

[bobbecky]

Not going to get in the discussion about which is better, but just wanted to throw this out there, synthetic oil is made from petroleum base stock. See this link: https://mobiloil.com/en/article/car-maintenance/learn-about-motor-oil-facts/synthetic-oil-vs-conventional-oil

[Pmedic4]

The 6.4 Liter Hemi in my 2500 says Synthetic is required, so it's an easy question for me. Fortunately, my dealer gave me 5 free oil changes when I bought my truck, so have always had it done at a dealership until this last trip.

I typically use the oil minder app in the truck and changed my truck based on the app. The only exception is when we took a Florida trip of 1500 miles one way, and changed the oil at about 4500 miles on the way down and then on the return trip.

I'm not even sure you can get the recommended weight of oil required in a non-synthetic oil, as the truck takes 0W40?

[gearhead]

Not going to get in the discussion about which is better, but just wanted to throw this out there, synthetic oil is made from petroleum base stock. See this link: https://mobiloil.com/en/article/car-maintenance/learn-about-motor-oil-facts/synthetic-oil-vs-conventional-oil
I agree, sorta. Read the link I posted bobistheoilguy.com and their comments on GTL (Gas to Liquids). Double cross oil company is just covering their rears on Mobil1.
PAO lubes are not distilled from crude in the conventional sense.
Sorry for the Exxon sarcasm…our major competitor and we just passed them for #1.
:D

[jack65]

I always thought synthetic oil was best for higher mileage motors (100+miles) and regular oil was fine for lower mileage motors. At least that was what the Corvette Forum were saying.
Any debate on that?

[busterbrown]

I always thought synthetic oil was best for higher mileage motors (100+miles) and regular oil was fine for lower mileage motors. At least that was what the Corvette Forum were saying.
Any debate on that?

I'm not sure that is widely accepted. High performance and heavy duty cycle vehicles benefit from the properties and additives in synthetics, even from the factory. Higher mileage vehicles will benefit too but there is the risk of leaks from seals if introduced after using conventionals for many miles. Well, that's at least what some oil fanatics say. All modern day cars and trucks can benefit from using today's superior synthetic oils.

[sourdough]

I always thought synthetic oil was best for higher mileage motors (100+miles) and regular oil was fine for lower mileage motors. At least that was what the Corvette Forum were saying.
Any debate on that?

The first time I used synthetic I used it on a vehicle that had maybe 20k miles, all using regular motor oil. I had problems with oil usage whether from leaks or oil burning; I don't know. I stopped and figured the "synthetic" hoopla was pure hype (decades ago). Fast forward to 10--12 years ago and I decided to start using synthetic in a new car I bought (all my cars are bought new). Noticeably cleaner oil; no usage. Then, modern cars came out with it as OEM. I've had superior results running it and wouldn't run anything else anymore. Just my thinking - to each his own.

[jack65]

I was mostly curious to what you guys were running on your rigs.
What my manual says is attached screenshots.
I ran Mobil 1 synthetic oil in my high performance Corvette for years.
I usually go by what my mechanic of 20 years tells me... he has never failed me yet. Him and his son, grandkids all have Ford/Ram pickups.
So, I'll ask him what he is running next time I see him. According to my gauge sensor says I'm 78% good at only 1,558 miles on last oil change. Pic attached.

I just got this pickup three months ago and only put 1,558 miles on it so far, so when the six months is up, I'll change the oil.

BTW, I was quite shocked:eek::eek: to see that the tranny oil was never to be changed and no dipstick either for a 8 speed tranny. 120K if you have a 6 speed.
It looks from what most of you say here that "Synthetic Oil" is the way to go.
I likes the Mobil 1 Synthetic Oil I ran in my Corvette:

(http://1-4u-computer-graphics.com/1977.htm) Question is, many say the Amsoil or Purple Synthetic better than the rest or now. Seems Mobil 1 did a good job for me.

[busterbrown]

It looks from what most of you say here that "Synthetic Oil" is the way to go.
I like the Mobil 1 Synthetic Oil I ran in my Corvette:

(http://1-4u-computer-graphics.com/1977.htm)

Amsoil and Redline are heavily promoted on the RAM forum as they deliver good Blackstone OA results when used in our Hemi engines. PUP is next up.
Surprisingly, Mobil 1 synthetic doesn't live up to it's reputation with our trucks. I've seen several OA's with Mobil 1 and will not use it. I've elected to stay with PUP for the duration of my ownership. Redline and Amsoil aren't as readily available. Although I would use them too if price and availability weren't a concern.

[sourdough]

I don't really look to forums to tell me what is good or bad...on anything usually - too many folks doing too many things for too many reasons with too many things looking for....?? I try to read technical results, particularly those that apply to me.

I've ran Mobil 1 in many vehicles now for many years and use Wix premium filters and my vehicle oil looks just really good with zero problems with oil, usage or getting dirty.

Just as a thought, Toyota, which I figure everyone understands is probably one of the best engine builders out there, uses Mobil 1. Just food for thought. My son in law swears by Amsoil because he can stop doing oil changes except for 15k miles....I'm out.

[gearhead]

My final words. I do admit to using Mobil1 in a Corvette. Don't tell the boss. LOL
Most of the name brand oil based synthetics when paired with a decent filter will do just fine when changed at recommended intervals.
The PAO synthetics are a bit better but their main advantage is extended oil change intervals, which will likely raise serious issues if you file a warranty claim.

[JRTJH]

Since almost all of this is opinion rather than fact, I'd opine that the subject of synthetic vs fossil oil is much the same as whether you can get drunker on wine or beer? Both do the job, both come in bottles (or for oil, in plastic/cans) and both are usually sold in the same store.

Years ago (before synthetics) I refused to use Quaker State oil (paraffin based) because of the "gunk" that accumulated under the valve covers. I used Pennzoil which was (I believe) sulfur based. I had clean valve covers every time I took them off to adjust the tappets. Made me happy, but my neighbor always smiled as he used old T-shirts to wipe out his Quaker State gunk was just as happy. Now that synthetics and blends are available, I tend to use what the engine manufacturer recommends. They built the engine, specified the oil requirements and provide (usually at a competitive cost) products under their name that meet those requirements. Makes it easy to maintain the engine "IMHO"....

Point being, this discussion, more opinion than fact, is just that..... OPINION....

Use the oil that makes you feel "warm and fuzzy" without regard for what makes your neighbor's "fuzziness smile".....

YMMV

[boxcar]

sourdough makes a good point about trusting forums and busterbrown brought up Blackstone Labs so I'll add that I prefer to seek information from real-world testing rather than the religious wars and marketing hype. Certainly, Blackstone has a business to run and promotes their testing service, but they have nothing to gain by promoting one oil over another as you'll see in this newsletter:

https://www.blackstone-labs.com/Newsletters/Gas-Diesel/July-1-2017.php

The net result on synthetic brands: "We just don’t tend to see much difference in wear metals between different oil types, so whichever one you want to use is fine.”

I had my dealership replace the break-in oil with synthetic at 1000 miles, sent a sample to Blackstone, and change at 7000 mile intervals on their recommendation. I let Ford use whatever brand synthetic they use and I'll use whatever is on sale when I start changing the oil myself soon. I expect to be buried in this 6.7L so I hope I'll need a half-million miles out of it. But I said that about my 7.3L and sold it at 1/4 million.

[sourdough]

sourdough makes a good point about trusting forums and busterbrown brought up Blackstone Labs so I'll add that I prefer to seek information from real-world testing rather than the religious wars and marketing hype. Certainly, Blackstone has a business to run and promotes their testing service, but they have nothing to gain by promoting one oil over another as you'll see in this newsletter:

https://www.blackstone-labs.com/Newsletters/Gas-Diesel/July-1-2017.php

The net result on synthetic brands: "We just don’t tend to see much difference in wear metals between different oil types, so whichever one you want to use is fine.”

I had my dealership replace the break-in oil with synthetic at 1000 miles, sent a sample to Blackstone, and change at 7000 mile intervals on their recommendation. I let Ford use whatever brand synthetic they use and I'll use whatever is on sale when I start changing the oil myself soon. I expect to be buried in this 6.7L so I hope I'll need a half-million miles out of it. But I said that about my 7.3L and sold it at 1/4 million.


This is a little off topic, but;

Where did you find a place that would let you get buried in your truck?:) I'm thinking that would be a great alternative to a $10k fancy box - and it would be paid for and comfortable for..... "the ride". :D

[boxcar]

I was just planning on digging a hole at the farm - wasn't going to ask anyone.

Speaking of a 10K box, I really do have an agreement with my granddaughters that they'll hand decorate a pine box and put me in the cemetery a mile from the farm. My great grandfather paid $100 for 12 plots there and there are still 3 vacancies. I have no intention of wasting money on anything except a fantastic wake with all the grandkids there.

[Big Boy w/ Big Toys]

You know I will throw one more monkey wrench at this subject....how about running Diesel rated oils in your gas trucks? They have higher additive/detegent packages for carbon, better shear stability and a few other things that gas only oil does not have.When you look at diesel oil is rated for CK and SN....Gas oil has only the SN rating.....I run Amsoil 5w-40 diesel oil in everything I own....well except for the motorcycles, those get the 15w-40 diesel oil treatment. I got a high performance 4 cylinder with 150k and running strong even being abused regularly. The lawn equipment don't care, the work trucks love it and our water pump-s that run WOT all day long never miss a beat.

[GrumpyCat]

I read once that synthetic blends are a waste of money. There's no regulation on what constitutes a synthetic blend or semi-synthetic. Is it 80/20? 50/50? Only the manufacturer knows and they aren't telling.

You are partially correct. There are no performance requirements or specifications for a motor oil to be sold as synthetic, not just semi-synthetic. The only requirement is that accepted synthetic methods be used for manufacture. There is no requirement of the end product.

There are no reputable specifications or requirements which stipulate use of synthetic motor oil. Those who stipulate synthetic do not know of which they speak. Sadly this sort of thing is sneaking into owner's manuals.

There are performance specifications for which no motor oil other than synthetics have met, but the specification does not say synthetic is required to meet. And not all synthetics meet the spec.

Buy Mobil-1 (or whatever) because it is a proven product, not because it is labeled "synthetic".

[GrumpyCat]

The first time I used synthetic I used it on a vehicle that had maybe 20k miles, all using regular motor oil. I had problems with oil usage whether from leaks or oil burning; I don't know. I stopped and figured the "synthetic" hoopla was pure hype (decades ago). Fast forward to 10--12 years ago and I decided to start using synthetic in a new car I bought (all my cars are bought new). Noticeably cleaner oil; no usage. Then, modern cars came out with it as OEM. I've had superior results running it and wouldn't run anything else anymore. Just my thinking - to each his own.

In ancient times the admonition was to never change the exact brand and model of motor oil after break-in for fear of leaks. It was understood the seals were saturated in whatever oil and once used to that oil sealed best with that oil, synthetic or refined didn't matter.

Then the synthetic guys came along not really knowing all the history and folklore of motor oil so they started over, repeating mistakes of the past. Pretty much like Elon Musk and Tesla manufacturing. The synthetic guys didn't know they needed to provide seal swelling agents which other oils were adding in varying amounts.

If you were using a motor oil with lots of seal swelling agents then your seals swelled up nice and tight, and wore faster. Another oil comes along with less swelling properties and suddenly your seals are worn and loose. And of course oil manufacturers bragged their oil didn't leak from your engine because it was better!

Today seal swelling properties are part of the SAE/API and everyone else's industry specs. The oil seal manufacturers know. The oil manufacturers know. Everything is now compatible.

[larryflew]

I put a LOT more miles per year on both of our Hemis. Dodge magnum is light use and have used regular Valvoline for 130K and change every 8k. Never on dirt roads and only highway driving. Durango 160K pulling 28 ft light weight trailer and a lot more hauling every 5K. Both have never seen any other oil and for the first half of their lives Fram filters. Switched to better filters but same changes. Neither used oil. Durango went with truck and trailer trade to GMC 1 ton and 16K trailer so totally different ball game.

[Frank G]

It would be nice if those that make a post that we, the reader, are to take as creditable information please give us some background or cite references. Other than that it is just another opinion, and there is nothing wrong with expressing your opinion.

[sourdough]

In ancient times the admonition was to never change the exact brand and model of motor oil after break-in for fear of leaks. It was understood the seals were saturated in whatever oil and once used to that oil sealed best with that oil, synthetic or refined didn't matter.

Then the synthetic guys came along not really knowing all the history and folklore of motor oil so they started over, repeating mistakes of the past. Pretty much like Elon Musk and Tesla manufacturing. The synthetic guys didn't know they needed to provide seal swelling agents which other oils were adding in varying amounts.

If you were using a motor oil with lots of seal swelling agents then your seals swelled up nice and tight, and wore faster. Another oil comes along with less swelling properties and suddenly your seals are worn and loose. And of course oil manufacturers bragged their oil didn't leak from your engine because it was better!

Today seal swelling properties are part of the SAE/API and everyone else's industry specs. The oil seal manufacturers know. The oil manufacturers know. Everything is now compatible.


Ancient times?? What? Those experiences were in the 70s (seems like yesterday :) ) when I was in my 20s - 30s....I'm not THAT old!! Here I am, fighting with a torn rotator cuff, torn bicep tendon feeling like I'm falling apart:( , and then, implying I'm ancient!!:facepalm: No wonder I'm not motivated today...:lol:

[Frank G]

Back in the 70's when Amsoil was gaining traction in the market you were asked to drain and add one Qt. of Amsoil to clean the engine, as the product had a cleaning effect in the crankcase. After a 1,000 miles or so you were ok do the oil change. It wasn't long before they started to market a engine cleaner and flush. They also provided warnings of oil leaks in higher mileage engines. My past brother was a successful dealer with regular 5 figure quarterly commission checks.

[Sk734]

Engine flush. 1/2 cup of kerosene-let it idle 10 minutes then drain and put in new dino. You would see a lot of sludge come out-back in the 70's. Cheap flush. GM now calls for dexos rated oil and I run it since it is under warranty. No oil usage 66K. Silverado 2500. 6.0 Gasser. Change when DIC says to. Before this I always changed at 5K. Great post.

[ron130fe]

My 2 cents, I have a 2014 Ram 1500 bighorn 5.7 and I’ve been running Synth since I got it (used)and I run it till the change oil gauge gets to about 10-15 %. Somewhere around 7500 miles, I have 57000 and will never go back to regular oil. Now my wife has a 2015 Ram 2500 longhorn and on the oil cap it says to use synthetic. So that’s my 2 cents, hope it helped

[gearhead]

Fiat Chrysler has a relationship with Shell. My Ram Cummins owner manual recommended 15W-40 Rotella or 5W-40 synthetic Rotella for extreme cold temps.
May have something to do with the Shell Ferrari (Fiat) long time relationship.

[Whitewolf]

When I had my '11 Ram with a 5.7, I used Amsoil. I even installed a bypass system. Used the 25K oil and filters. Changed everything at 20K. Just cause.

Been using Amsoil since the '70's. First car to use it was a Honda CVCC. Had to adjust the lifters every 10K miles and was always amazed at how clean the valve train was.

Now in my Ram 6.7 Cummins. Oil, oil filter and both fuel filters are changed every 15K.

[UsTwo]

So on my 2013 Ram Hemi 5.7, I ran synthetic for the first few years, than started running just regular oil after awhile. couldn't tell the difference, So now my 2016 says to run Synthetic, so I am, but just in camping season.. I run regular oil in the winter time, with a dash of Marvel Mystery Oil. learned of the mystery oil through some vintage Volkswagen folks..Really just run with what feels right to you..

[fjr vfr]

You have an owners manual that spells out when to change the oil. You should read it and follow what it says. Anything else is opinions, some right some wrong. You can't go wrong following the owners manual. The engineers that designed the engine wrote the book. I would think they know something about the subject. IMHO

[jack65]

I was told on the Corvette C3 forums that if you've been using regular oil on the older Corvettes and then switch to synthetic oil, never go back to regular oil as your engine will start leaking.

I don't know if that is a fact or not, but I never went back to regular oil. Used Mobil 1 synthetic oil for 8 years on this:
http://1-4u-computer-graphics.com/1977.htm

[sourdough]

I was told on the Corvette C3 forums that if you've been using regular oil on the older Corvettes and then switch to synthetic oil, never go back to regular oil as your engine will start leaking.

I don't know if that is a fact or not, but I never went back to regular oil. Used Mobil 1 synthetic oil for 8 years on this:
http://1-4u-computer-graphics.com/1977.htm


Nice Vette Jack! That synthetic sure made the car look so much better!!:D

[jack65]

Nice Vette Jack! That synthetic sure made the car look so much better!!:D
LOL!:lol: Here are my other ones over the years:
http://1-4u-computer-graphics.com/jacks-vettes.htm