Power steering cooler and cavitation during winter

[lordoeuf]

Is it typical to have power steering issues during winter months while the Jeep is cool, but fine once it is at operating temperature? I live in a mild climate, so daytime highs are usually 5 - 9 C during winter.

I have a '99 XJ 5-speed, and am using the stock automatic transmission cooler as a power steering cooler (mainly because I have a PowerTrax no-slip locker in the front diff). I'm using 3/8" transmission cooler hoses and hose clamps for the power steering cooler. Length to and from the trans. cooler is about 4.5' each way. I have a '98 Durango gear box that I rebuilt and a Lee Power Steering pump.

I am noticing that when I first leave the garage to get the kids from school, the steering is a little stiff, but by the time I return home, it has loosen up and the Jeep drives as I would expect. Is the power steering cooler somehow causing air to get into the system, or keeping the fluid too cool causing cavitation? I read on google that this issue isn't all that uncommon during the winter when you have a power steering cooler, but I don't know how true this is. I park the Jeep in a garage that stays at about 16 C in winter and outside isn't that cold.

Any idea how to fix this? I would like easy turning right when I leave the garage. I added about a 1/8 a bottle of Blue Devil Power Steering Leak stop thinking that perhaps the change in temperatures is causing some air to get past a fitting, but it didn't solve anything. I don't have any visible leaks. Perhaps there are other conditioners I should use that will solve the problem?

If the vehicle is cool and I start it up with the reservoir cap off, I don't see any bubbles coming up when turning the wheel. With the car cool, I can also raise the front wheels off the ground and turn the steering wheel lock-to-lock like a mad man about 20 times. This definitely causes bubbles to appear in the reservoir, but if I turn the vehicle on and drive out at this point, the steering feels fine.

[75SV1]

I'd try a few things. First did you follow the new gear box purge procedure? As you described, you lifted the tires up and then lock to lock.
The factory is tube and fin. I might look into a B&M cooler. The ones with the fixed nipples are suppose to by-pas cold oil. Then allow hot oil to run through the plates. Another is maybe a synthetic PS Fluid. I bought some Lubeguard at Oriely's. I haven't used it yet though. I did run some Royal Purple in my MB 240D.
I'd also probably contact the company you made your gearbox, since you mentioned Lee. I might look into getting one of those on my next build. Do you like yours?

[RCP Phx]

Considering the viscosity of mineral oil I doubt it would be a issue unless you had extreme cold temperatures.

[Jim Malcolm]

You could consider ATF. Ford and a few other manufacturers use it in their systems. GM has a special PS Fluid that has much the same properties of ATF. The viscosity of ATF is about 2/3 that of PS Fluid (for Lucas products at least). In my job, we use ATF for low temperature applications with a similar style of pump.

[Jim Malcolm]

You could also use a thermostat

https://www.summitracing.com/search/...il-thermostats

[lordoeuf]

75SV1: I don't have a new gear box. I have a 1998 Dodge Durango gear box (from a salvage) that I replaced all the seals in. I've been driving with new seals for about 6 weeks now. I am using only GM's power steering fluid. Heh, my other car is a 240D! It is a pleasure to work on. I've had it for decades.

Jim Malcolm: Already using GM power steering fluid.

Could it be that that the 9 feet of 3/8" if tranny cooler line slows pump down when cool?

One other thing I noticed is that the factory return hose sort of acts like a bladder in that it opens up in the middle to increase volume. Is there supposed to be some expansion in the hoses on the return? Because the 3/8" transmission cooler hose I am using now doesn't have this expansion built into it. I figured this type of fluid expansion would happen in the reservoir rather than the hose, but...?

I was considering bypassing my tranny cooler, but I'm pretty sure I chucked the factory return hose. It would be nice to have an AN6 type connection straight from the Lee Pump to the Durango gear box. Does anyone make a pre-crimped AN6 hose or pipe for this purpose on an XJ? The Lee pump has an AN6 fitting on it already, which at present goes to a barb adapter, so I'd need an AN6 adapter for the gear box and then some pre-crimped hose or pipe to go from the gear box to the pump.

[RCP Phx]

I don't see how your hoses are that long but....... you can make your own AN hoses.
https://naxja.org/forum/showthread.php?t=1148990

[lordoeuf]

Originally Posted by RCP Phx

I don't see how your hoses are that long but....... you can make your own AN hoses.
https://naxja.org/forum/showthread.php?t=1148990

If you are mounting the cooler in the stock transmission cooler location, I don't see how the hoses could be any shorter. With routing, it is about 4-1/2 feet to the cooler, and about 4-1/4 feet back. That's 9 feet. Stock hose without the cooler is only about 18", so that is 7-1/2 feet more hose than stock.

I was just hoping for a simple pre-made AN6 line so that I can do a quick test to bypass the trans cooler. Otherwise I have to start yanking the hoses off the barbs and cut a new like. When I look at Lee's website, there's about a dozen options for AN6 on a "Saginaw GM gear box", https://leepowersteering.com/collect...ering-fittings

[Black1990jeep]

In order to insure complete expelling of all the air, the cooler must be,mounted below the fluid level in the reservoir. I had issues on mine until I lowered the cooler below the fluid level, then it worked fine, got quiet. I read that advise, thought about it, it made sense, then tried it. So always mount the cooler below the reservoir fluid level. no part of the cooler, nor cooler hoses should be above the reservoir fluid level, else air will be entrapped, and pump will be noisy, and have its life ruined.

I too have that Dodge gearbox, works well.

[lordoeuf]

Thanks. Yes, every part of the cooler and its hoses are below the fluid level in the reservoir.

I've decided that I am going to back track in my troubleshooting process. I'm going to entirely disconnect the cooler's lines and connect the pump direct to the gear box using new high and low pressure line assemblies from Edelmann, 80290E for the HP side and 80402 for the LP side. Using new lines will at least remove some question I have in my mind about the original Jeep HP line and LP pipe end. Being in Canada, I have to wait for parts, as always. Won't be until next week.

Another thing I was thinking about is that this reservoir, even though there is air in the bottle, that air isn't at ATM; it is pressurised to at least the open end of the LP line. Perhaps 30-50 PSI? Seems like it might help with aeration to have some kind of check valve at the top of the cap to reduce the air pressure further. Check valves can be ordered with all types of forward cracking pressures.

[RCP Phx]

Originally Posted by lordoeuf

If you are mounting the cooler in the stock transmission cooler location, I don't see how the hoses could be any shorter. With routing, it is about 4-1/2 feet to the cooler, and about 4-1/4 feet back. That's 9 feet. Stock hose without the cooler is only about 18", so that is 7-1/2 feet more hose than stock.

I was just hoping for a simple pre-made AN6 line so that I can do a quick test to bypass the trans cooler. Otherwise I have to start yanking the hoses off the barbs and cut a new like. When I look at Lee's website, there's about a dozen options for AN6 on a "Saginaw GM gear box", https://leepowersteering.com/collect...ering-fittings

I guess it would depend on your routing. My set-up only has about 4-1/2' of line in total.

[lordoeuf]

Originally Posted by RCP Phx

I guess it would depend on your routing. My set-up only has about 4-1/2' of line in total.

Yeah, but you have proper elbows and such. Without elbows, you generally want to avoid sharp corners or those with a small radius of curvature, esp. when routing rubber hoses. You also aren't using the factory pipes which come out of the gear box. In the case of the return pipe, it is going 180 degrees in the wrong direction when routing hose to a PS cooler. With a completely custom job like yours, I can see how you only needed half the length of hose. Perhaps I'll go your route, but I'm not there yet. I'm pretty burned out on the Jeep as it is.

If removing the PS cooler fixes the issue, I may just hook the AUX fan up to the fog light switch and turn it on while wheeling. Forget the cooler. The Lee pump reservoir is all aluminum, so it acts as a heatsink. What's better is that the AUX fan points right at the reservoir.

[Black1990jeep]

Originally Posted by lordoeuf

Thanks. Yes, every part of the cooler and its hoses are below the fluid level in the reservoir.

I've decided that I am going to back track in my troubleshooting process. I'm going to entirely disconnect the cooler's lines and connect the pump direct to the gear box using new high and low pressure line assemblies from Edelmann, 80290E for the HP side and 80402 for the LP side. Using new lines will at least remove some question I have in my mind about the original Jeep HP line and LP pipe end. Being in Canada, I have to wait for parts, as always. Won't be until next week.

Another thing I was thinking about is that this reservoir, even though there is air in the bottle, that air isn't at ATM; it is pressurised to at least the open end of the LP line. Perhaps 30-50 PSI? Seems like it might help with aeration to have some kind of check valve at the top of the cap to reduce the air pressure further. Check valves can be ordered with all types of forward cracking pressures.

My steering fluid reservoir cap IS vented. Factory type 1990 XJ even has provision to add a breather hose. Thus the reservoir should not pressurize. Now my buddy has a 2001 XJ and his cap has no hose nipple, but his cap is maybe vented out thru the threads or such, different design cap. But for sure the 1990 has a vented cap, with a hose nipple even although factory never installed the hose.

If you think vented is needed, I have a hunch the cap is vented anyway (maybe your vent is clogged) test by setting your cap on loose to see if it makes a difference if it does, then clear your vented cap vent or get a vented cap.

[techno1154]

Originally Posted by Black1990jeep

If you think vented is needed, I have a hunch the cap is vented anyway (maybe your vent is clogged) test by setting your cap on loose to see if it makes a difference if it does, then clear your vented cap vent or get a vented cap.

There is a little rubber vent/one way hose built into the new style caps. If you were to separate/remove the top of the cap using a tin blade screw driver you would find it there. You do not have to remove the cap from the reservoir.

[lordoeuf]

I have the Lee Power Steering pump, which includes an aluminum reservoir with a Lee cap. From what I can tell, there isn't any venting on the cap or the reservoir. When I open the cap, I can hear a sound like the release of pressure, sort of like when you open a soda pop bottle. So the air is definitely pressurised in there and not at ATM.

After driving the car with a stock pump/reservoir, do you not hear that "pop" when you remove the cap? On the Lee pump, if I turn the wheels lock to lock a few times then remove the cap, I hear a "pop".