Jeep Grand Cherokee blows power steering pumps when towing.

[C.LeeNick]

I've posted this on a couple dedicated Jeep Grand Cherokee forums, and have covered the issue with three Jeep dealer service departments, as well as dozens of other people.

Haven't found an answer yet, so figured I'd run it by you folks.

We tow our Passport trailer with a 2004 Jeep Grand Cherokee, and have had several long successful journeys over the last year where the Grand has towed the trailer just fine. The Grand Cherokee Overland has a tow rating of 6500 pounds...and the Passport weighs about 4600 dry. Even loaded, I cannot imagine it weighing more than 5100-5200 or so. Well within spec.

We took a trip to eastern Nevada about 7 weeks ago. During that trip, we blew a power steering pump while towing the trailer. It was the factory pump on the Grand Cherokee, which we purchased with 67,000 miles on it, which currently has about 91000 on it. At the time, we chalked it up to age and bad luck, replaced the pump, and continued our trip with no issues. We probably put another 1000 miles on during that trip.

About 4 weeks ago, we took a trip through northern Nevada, across U.S. 50, to Reno and back. Second day out, we blew the new power steering pump about 300 miles from home. It was warranted, so we replaced it. The very next day, that pump blew as well, after about 250 miles.

We were "stuck" in Ely, Nevada while NAPA ordered us another power steering pump. The first two were from Autozone, but in Ely, NAPA is the only game in town, and the nearest Autozone was well over 100 miles away. Doing a lot of reading onlne while in Ely, we found that some pumps for the Grand Cherokee were being shipped with the incorrect flow-control fitting in them. The Autozone pumps matched that description. When we got the NAPA pump, the fitting was the correct one, and we thought we had it all figured out. Indeed, we put about another 500-600 miles on, going all the way to Reno pulling the trailer, then unhooking and driving around for a few days, and then hooking up and heading back across Hwy 50 towards home.

About 250 miles into the return trip, the NAPA power steering pump blew as well. We ended up leaving our trailer in Eureka, NV, jetted home in the Grand Cherokee with no power steering, and I went back with our pickup (650 miles one way) to retrieve the trailer.

Each pump failed by blowing the seal around the pulley shaft.

Here's the rub, and the reason we left the trailer behind: In the 2004 Grand Cherokee, the power steering pump runs the cooling fan, which is a hydraulic unit (Which I have now determined is a very stupid idea). There is no mechanical or electric fan. Supposedly, the hydraulic fan is part of the "heavy-duty" cooling package expressly FOR towing. Each time the pump failed, the cooling fan became inoperable to some degree..and when the pump failed completely and would hold no fluid, the fan would stop completely. As long as we drove fast, enough air passed through the radiator to keep the vehicle cool. That's how we got it home.

How the power steering/cooling system works is that the power steering pump feeds the hydraulic fan high pressure first, then, at the hydraulic fan, the line splits and one low pressure line returns to the pump while another high pressure line goes from the hydraulic cooling fan to the steering gear, then from the steering gear, another low pressure line goes back to the pump.

The pump has one high pressure outlet to feed everything, and two low pressure returns, one from the hydraulic cooling fan, and one from the steering gear.

So far, the issue is a total puzzle. Jeep techs I've spoken with have no clue. I've even contacted Valeo, the designer/manufacturer of the hydraulic cooling system (Also used in other Chrysler vehicles), and have been getting the runaround, but no answers, from them. And I've found no similar issues regarding reoccurring pump failure, except for some speculating that it's all due to bad power steering pumps. I could accept that the replacements were bad, IF the factory original pump hadn't blown in the exact same way first.

I'm putting my fifth power steering pump in 7 weeks on this morn. The only other hint I can give is that it all seems to be associated with pulling the trailer, in that during the time we are pulling steep grades (There were many 7000 foot passes on our route) the vehicle would shift down into second gear and wind up the RPM's during that time, which SEEMS to be associated with blowing the power steering pump. Of course, we thought we had it all figured out before, and it turns out we knew nothing.

This issue is really puzzling me. Any ideas?

Thanks!!

P.S. While the issue with the Grand Cherokee was a pain, it didn't totally ruin our trip. We had planned on staying in Ely a couple days because there is a lot to do around there..including taking a ride on a steam train, so we had more time to do that stuff.

[JRTJH]

Several thoughts:

1. Have you considered a Chrysler OEM pump? Sometimes there's a "little difference that makes a BIG difference" between the manufacturer's part and the aftermarket part... It may not be significant in this case, but it may be that NAPA and AutoZone both buy from the same "remanufacturer" and both are deficient.....

2. You allude that your trailer's "dry weight is 4600 pounds so loaded it "can't be more than 5100-5200 pounds". Have you dragged it across a scale to see how much it "really weighs" ??? Often times people "guesstimate" their weight and typically, it's well below the "reality weight"... Get thyself to a scale so you know for sure.

3. If you're using a weight distribution hitch and overloading the front axle, then that "overload" may be the reason you're having problems with the power steering. Again, an accurate weight of the front axle, rear axle, trailer axle followed by a weight of the Jeep front axle and rear axle without the trailer will give you some "real world data" that may solve your problem by reducing it to "front axle overload". I'm not suggesting that it definitely is overloaded, but without weights, it's anybody's best guess......

[Canonman]

I'm not the guy who knows the answer to this complicated question but I would trust Brock Besner at Premier Auto Care in West Jordan: http://www.premiercompleteautocare.com/
These guys know their stuff and are RV'rs too

[Ken / Claudia]

Sounds like the simple answer is the vehicles not up to the task, is it from the needed extra power or even the extra heat built up while towing, who knows. Not sure many know this and if the other HD trucks have this. Ford HDs have a real power steering cooler mounted in the grill.

[C.LeeNick]

Originally Posted by JRTJH

Several thoughts:

1. Have you considered a Chrysler OEM pump? Sometimes there's a "little difference that makes a BIG difference" between the manufacturer's part and the aftermarket part... It may not be significant in this case, but it may be that NAPA and AutoZone both buy from the same "remanufacturer" and both are deficient.....

2. You allude that your trailer's "dry weight is 4600 pounds so loaded it "can't be more than 5100-5200 pounds". Have you dragged it across a scale to see how much it "really weighs" ??? Often times people "guesstimate" their weight and typically, it's well below the "reality weight"... Get thyself to a scale so you know for sure.

3. If you're using a weight distribution hitch and overloading the front axle, then that "overload" may be the reason you're having problems with the power steering. Again, an accurate weight of the front axle, rear axle, trailer axle followed by a weight of the Jeep front axle and rear axle without the trailer will give you some "real world data" that may solve your problem by reducing it to "front axle overload". I'm not suggesting that it definitely is overloaded, but without weights, it's anybody's best guess......

Thanks for the reply!

Re: MOPAR pump. New pumps have been discontinued by Chrysler, but they do offer rebuilt pumps. It's possible a MOPAR rebuilt could be better than aftermarket, so that could be an option if I cannot find anything else wrong with the system.

Re: Trailer weight/weight distributing hitch. I have no clue where to go in my area to weigh the vehicle. We're a pretty small town not close to any interstates, so there are no truck stops or trucking facilities that I know of. But I'll check into it. As far as the tow rating, I'm certain I'm not close to the vehicle's stated rating, and indeed Chrysler states that the tow rating is 6500 only if a weight distributing hitch is used. Otherwise, the two rating is 5000. I am using a weight distributing hitch. What's more, Chrysler states that the hydraulic cooling fan run by the power steering pump is part of the "heavy-duty" towing package. They de-rate the tow rating to 5000 lbs if the vehicle does not have the hydraulic fan.

I did find an outfit online that sells a new MOPAR power steering pump for my year of Grand Cherokee for $375..but then they state that it also requires ordering a new power steering fluid tank because my old one won't fit. New tanks are about $80. I'm not quite to the point of taking that gamble without making sure there isn't some other faulty component of the system causing the pump to blow. I'd hate to blow a $450 plus pump in a couple hundred miles.

[C.LeeNick]

Originally Posted by Canonman

I'm not the guy who knows the answer to this complicated question but I would trust Brock Besner at Premier Auto Care in West Jordan: http://www.premiercompleteautocare.com/
These guys know their stuff and are RV'rs too

Thanks! I live in New Mexico, we were traveling through Utah when the second pump blew, but the vehicle is back in New Mexico now. Maybe they could help over the phone though if they've had experience with this kind of issue. I talked to tech support for the power steering rebuilder yesterday, a fellow in Phoenix. He said this repeated power steering pump failure issue with the Grand Cherokee is a new one on him. He gets a lot of calls for noisy pumps, however, so he gave me some tips on the proper bleeding procedure that I didn't know before.

[C.LeeNick]

Originally Posted by Ken / Claudia

Sounds like the simple answer is the vehicles not up to the task, is it from the needed extra power or even the extra heat built up while towing, who knows. Not sure many know this and if the other HD trucks have this. Ford HDs have a real power steering cooler mounted in the grill.

Howdy!

I've considered the vehicle not being "up to the task". However, it was "up to the task" for a year before this problem started, and lots of people tow with Grand Cherokees with hydraulic power steering/cooling fan systems and have not had this issue. Frankly, so far, I'm stumped, but I haven't given up yet.

I've even questioned the feasibility of the hydraulic cooling fan in concert with the power steering in general, and am still considering retro-fitting to a mechanical/electric cooling fan combo as used in 1999-2000 Grand Cherokees with the heavy duty tow package. However, folks on the Grand Cherokee specific forums state a properly operating hydraulic fan is far superior to the mechanical/electric combo in that that it not only moves more air, but it robs less horsepower from the engine.

I've found it ironic that the hydraulic cooling fan is part of the "heavy-duty towing package". Chrysler knocks 1500 lbs off the tow rating if the vehicle doesn't have it. Yet at this point, it's not working for me.

Until I bought this Grand Cherokee, I'd never even heard of hydraulic cooling fans. Now, after hours of reading about them, I see Chrysler used them in all sorts of vehicles..including Dodge Ram trucks and the Viper, and in the Jeep Commander. They seem to be pretty trouble free. Perhaps I'm the first person to experience this exact issue. They also seem to be used in a lot of diesel pusher motorhomes. Interesting tech, but I'm still not sold on 'em.

Believe me, I'm seriously considering getting a different two vehicle entirely. We're looking at GMC Sierra 2500's and Ford Super Dutys. I bought the travel trailer specifically to fit the tow rating of the Grand Cherokee. If I end up having to now buy a different tow vehicle, I'm going with overkill. The GMC Sierra Duramax diesel I test drove had a 15000 lb tow rating. That should pull a 5000 lb trailer I would think.

[C.LeeNick]

One thing I forgot to mention is that the Grand Cherokee for 2004 does have a separate power steering cooler in the grille, ahead of the radiator.

Also, the several replacement pumps have "blown" at the seal around the pulley shaft. The bearing itself is fine. No wobble in the shaft at all. It appears there is an over-pressure issue. This is what occurred with the original MOPAR power steering pump that blew about 7 weeks ago, and the problem has been identical in every replacement pump so far.

[Wyldfire]

High temp, high altitude, high weight pushing the pump past it's limit?

[hankpage]

Let's think out of the box here. Since all pumps including original have failed with what seems to be over-pressure, was anything changed before the first one failed???? (pulleys, belt or belt routing) Increased speed of pump would increase pressure. Since your problem seems to be unique, I would be looking for something that makes it different than others.
Over the years I have owned many Mopar vehicles and have seen them use different fluids on similar systems and changing mid-stream by year or serial # so forum info is not always the most reliable. (Unlike this one )

Just thinking out loud, Hank

[JRTJH]

To go a tad bit further than Hank's comments, a partially plugged bypass valve in a steering section ram or a kink/plug in a return line from the steering actuator or a partial plug from a part of the piston seal that is clogging the hydraulic orifice in the cooling fan motor ???? I'm grasping at straws more than helping, but if one of the "not yet replaced" components in the system has a plugged/partly plugged hydraulic flow, the back pressure may be building up in the pump causing the piston seal to blow.... It would seem to me that there should be a pressure regulator within the pump to prevent overpressurization, but "engineers" (term used lightly) sometimes forget the obvious with the thought that "Ah, it'll never happen that way".... Which could lead me to a year long discussion of recalls on airplanes that are engineered to the "nth" degree and still we find situations we never dreamed of... So, Chrysler may have overlooked something as simple as a bypass regulator in the pump, never thinking about a plugged actuator on the steering system component "down the line from the pump" causing backpressure that blows the piston seal......

[travelin texans]

Mopar dies a lot of unique stuff!
We bought a used Jeep Commander with only 20k miles on it but the battery had been replaced with an Interstate. After 6-8 trips back to the dealer for electrical issues a new tech opened the hood & immediately said there's the problem, I said "WHAT?", he said the battery must be a Mopar battery, changed battery & no more electrical issues. I'd never heard of such a thing, but it worked, our daughter kept it for 100k miles, no more issues.

[C.LeeNick]

Originally Posted by Wyldfire

High temp, high altitude, high weight pushing the pump past it's limit?

I'm pretty certain towing the trailer has something to do with with the failures, but they shouldn't. We are well within the towing capacity Chrysler says we should be. And given the Grand Cherokee's unibody construction, I could see towing putting a lot of stress on other parts of the vehicle before it would stress the power steering/hydraulic fan. I'm thinking there is a defect in the hydraulic fan unit...the steering box is a pretty straightforward recirculating ball gearbox...no rack and pinion or anything fancy. In fact, if I retrofit to mechanical/electric fans, I can can leave the steering box in and switch to a lower flow pump like they used in 1999-2000, and on the 6 cylinder Grand Cherokees. Apparently that pump bolts right in. Then I can remove the hydraulic fan assembly and run lines directly from the pump to the power steering box like what's in almost every other vehicle in the planet.

It just so happens the hydraulic fan unit is not serviceable. There are no parts and no tech specs. It must be replaced as a unit, and they run between $800-$1100 for a new one. They have the capability to run at such high RPM they must be balanced at the factory. The rim of the hub of the fan blade has the provision for inserting different sized ball bearings into it in order to perfectly balance the fan. Unbalanced, I guess the fan blade has the potential to fly apart. Frankly, I'm finding the whole thing to perhaps be a far more technical and complex set up than was necessary.

As far as altitude and temperature, we drove from Farmington, NM, which is at about 5500 feet, through Utah and Nevada. The first failure occurred near Salina, Utah, which is actually a couple hundred feet lower than here. The highest passes we went over were in Nevada, at around 7500 feet max. Air temperatures in the area while we were there were cooler than usual...probably the warmest day we experienced was around 90, with lows in the 50's at night.

It didn't seem to be anything extreme. It's all quite puzzling.

[C.LeeNick]

Originally Posted by hankpage

Let's think out of the box here. Since all pumps including original have failed with what seems to be over-pressure, was anything changed before the first one failed???? (pulleys, belt or belt routing) Increased speed of pump would increase pressure. Since your problem seems to be unique, I would be looking for something that makes it different than others.
Over the years I have owned many Mopar vehicles and have seen them use different fluids on similar systems and changing mid-stream by year or serial # so forum info is not always the most reliable. (Unlike this one )

Just thinking out loud, Hank

I do agree Mopar can be pretty reliable. In fact, I went back to Nevada to get our travel trailer with our 1999 Dodge half ton that has 100,000 more miles on it than the Grand Cherokee, and I wasn't certain it would be up to the task since we'd "inherited" the truck from my father in law who doesn't drive anymore. He'd never taken it out of town and had bought it used. It's one of the Dodges that the dashboard cracks and falls out of and this one is no exception. But the thing ran like a champ and pulled the trailer wonderfully. I now trust that truck to go anywhere. I'd use if for my primary tow vehicle except it's kind of an "old beater truck"..A/C doesn't work. The decaying interior blows black dust all over you when you drive with the windows down, it's a standard cab, and it's two-wheel drive and we use 4x4 for exploration after we set up the travel trailer, etc. But it will make an excellent back-up tow vehicle for close in trips until we get the Grand Cherokee sorted out.

As far as the Grand Cherokee goes, it's stock. And it's been really reliable. In fact, the only problem I ever had with it was an apparent common issue of a fitting on the high pressure power steering line that has a teflon seal in it that fails, and is un-serviceable.. It leaked for a while, but quite by accident I used the correct spec of power steering fluid as a top off, and then replaced the line with a hose redesigned by Mopar with a fitting that uses a standard O-ring rather than the teflon seal. I did that before we even bought the travel trailer, so that was probably a year and a half ago or longer. We got a year of towing in before the things went haywire.

The only other thing I've changed is that it came with 235-75-17 tires and I replaced them with 245-75-15. Not much oversized. If that would cause the power steering to blow, the Chrysler cut it pretty close with the engineering. A lot of Grand Cherokees are built much larger with lift kits and with far more oversized tires.

As far as fluid goes, it does require a specific type, MS5931. They've even issued TSB's specifying that the spec MUST not be strayed from. In fact, MOPAR doesn't even offer the fluid anymore, but many aftermarket brands meet the spec, including Valvoline in the white bottle with blue label (which I special ordered in Ely, Nevada when we changed out the pump there), NAPA brand, and even Autozone store brand.

[C.LeeNick]

Originally Posted by JRTJH

To go a tad bit further than Hank's comments, a partially plugged bypass valve in a steering section ram or a kink/plug in a return line from the steering actuator or a partial plug from a part of the piston seal that is clogging the hydraulic orifice in the cooling fan motor ???? I'm grasping at straws more than helping, but if one of the "not yet replaced" components in the system has a plugged/partly plugged hydraulic flow, the back pressure may be building up in the pump causing the piston seal to blow.... It would seem to me that there should be a pressure regulator within the pump to prevent overpressurization, but "engineers" (term used lightly) sometimes forget the obvious with the thought that "Ah, it'll never happen that way".... Which could lead me to a year long discussion of recalls on airplanes that are engineered to the "nth" degree and still we find situations we never dreamed of... So, Chrysler may have overlooked something as simple as a bypass regulator in the pump, never thinking about a plugged actuator on the steering system component "down the line from the pump" causing backpressure that blows the piston seal......

I'm definitely leaning towards your way of thinking. It's just that the whole system is so exotic and mysterious I've had trouble finding anyone who knows how the dang thing works. Because the hydraulic cooling unit is not serviceable and must be replaced as a whole, there are no exploded diagrams, no specs, no replacement parts, no diagrams that show anything other than "hydraulic cooling unit". And it's a pretty expensive part to just "shotgun" and replace at $800-$1000. I feel that is where I'm going to end up anyway, though, because I need this vehicle to be reliable or I need to get rid of it. I'm considering just replacing the entire power steering/cooling system...cooling unit, steering box, lines, etc. (Already have a pump! )

I have found reference to a pressure regulating valve inside the cooling unit that I suspect MAY be the culprit, but the same write up that mentioned it says that it's designed in such a way that it's failure will not affect power steering...but exactly as you stated, it VERY likely something has happened in my system, or a combination of variables are lining up, that engineers never dreamed of.

[hankpage]

Originally Posted by C.LeeNick

As far as the Grand Cherokee goes, it's stock. And it's been really reliable. In fact, the only problem I ever had with it was an apparent common issue of a fitting on the high pressure power steering line that has a teflon seal in it that fails, and is un-serviceable.. It leaked for a while, but quite by accident I used the correct spec of power steering fluid as a top off, and then replaced the line with a hose redesigned by Mopar with a fitting that uses a standard O-ring rather than the teflon seal. I did that before we even bought the travel trailer, so that was probably a year and a half ago or longer. We got a year of towing in before the things went haywire.

.

This is where I would start to look for any restrictions that could cause pressure to increase or even a failure in the new hose. Just too many pumps for them all to be bad.

[C.LeeNick]

Originally Posted by hankpage

This is where I would start to look for any restrictions that could cause pressure to increase or even a failure in the new hose. Just too many pumps for them all to be bad.

I agree. Since the original, and all the replacements, have blown in the last 7 weeks or so, and in an identical way, I believe something has "gone wrong" in the system.

What's puzzling is there are no leaks elsewhere, no blown lines or seals (other than the pump), and as long as the pump is working, the steering and cooling fan appear to be working perfectly.

Hopefully, the testing procedures with the engine analyzer will provide a definite cause.

[66joej]

C.LeeNick just a suggestion. Seeing your Jeep is an '04 have you thought of going to a scrap yard (auto recycling depot) for replacement parts. There should be lots of wrecked or Jeeps with blown engines given the age of yours. You can get genuine Mopar stuff that will not cost an arm. YMMV

[Ken / Claudia]

I asked, google 04 jeep power steering failure and found 2 a 2010 and 2014 answers. They said air was getting into the system though a leak in the high pressure hose. They also gave advice to make sure all air is removed and the system gets flushed. There was more details but that's the main points.
Google just saved me 100 bucks on a vehicle problem I could not fix, I had no idea the fix was so simple, 5 mins and it was fixed. After watching a guy repair the same problem on you tube.

[McRod]

Replace the cooling fan, pump, hoses, and belt.