Is a power steering fluid bath bad for my truck?

l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Turns out the line into my steering fluid cooler had rotted. Last night it started gushing fluid. But today after getting it repaired fast, I looked around and noticed small puddles everywhere i had been parking lately. And the bottom of the truck is covered in the fluid.

So again I dropped it off at my mechanic and it's already fixed. But the fluid is everywhere. Is this a problem? In other words, is it going to be like motor oil where it just helps fight moisture and rust for a while until it all evaporates. Or is steering fluid a harsh fluid that might start eating away at metals and plastics and rubbers?

So I guess all I'm really asking is, should I try to clean the bottom of my truck? Or is it fine and maybe even helpful to just let it soak in power steering fluid?
 

c good

Member
Dec 8, 2011
526
Power steering fluid is basically like hydraulic fluid. I know that brake fluid if it gets on the paint will eat away the paint. I don't think it will eat rubber components as power steering rack and pinion has rubber seals in them. I don't think I would let it sit on any painted surfaces under the hood for very long. It could cause them to crinkle and peel off....eventually leading to exposed metal and rust.
 
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xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y
When a similar issue happened to my brother-in-law's TBSS we just sprayed the whole engine bay and whatever we could get to with simple green. Let it sit for 5 minutes and hosed it all down. Rag dried as much as we could and it cleaned up everything nicely.
I've also used simple green to clean the engine bay on the Envoy, been doing it for years actually and no ill effect from it or rinsing with water. The only thing I do cover so it doesn't get much water is the alternator. I just use a plastic shopping bag and fit it on as best I can.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Power steering fluid is like trans fluid. Some people use it for rust proofing. And unlike brake fluid, it will not make paint peel. I'd leave it. In fact, that's what I did on my TB recently when the cooler rusted out and leaked fluid everywhere but I did blot a rag around to pick up visible drips. I just bypassed the cooler for now. If you want, take it to an automated car wash that does an underbody flush. We have a lot of those here to wash away salt.
 
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l008com

Original poster
Member
Feb 19, 2016
886
Massachusetts
Power steering fluid is like trans fluid. Some people use it for rust proofing. And unlike brake fluid, it will not make paint peel. I'd leave it. In fact, that's what I did on my TB recently when the cooler rusted out and leaked fluid everywhere but I did blot a rag around to pick up visible drips. I just bypassed the cooler for now. If you want, take it to an automated car wash that does an underbody flush. We have a lot of those here to wash away salt.
I was surprised it has a steering fluid cooler. I always assumed that cooler was for the transmission. Is it common for vehicles to have steering fluid coolers? It doesn't seem like the kind of fluid that would tend to get all that hot. Unless maybe if you were driving around a race track all day! And yeah I may do just what you said, wipe the lip to get any big drips that might still be around and just leave the rest.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
I was surprised it has a steering fluid cooler. I always assumed that cooler was for the transmission. Is it common for vehicles to have steering fluid coolers? It doesn't seem like the kind of fluid that would tend to get all that hot. Unless maybe if you were driving around a race track all day! And yeah I may do just what you said, wipe the lip to get any big drips that might still be around and just leave the rest.
I think they started adding coolers with rack and pinion systems. Just like the trans, it can only benefit from lower operating temperatures. The low fluid capacity and being continually pumped can elevate temperatures especially when ambient temperatures are high. And if you think about it, city driving and mall crawling does use the power steering system a lot more.
 

SoundBass

Member
Apr 18, 2020
23
Sarnia ON
My cooler rotted out in my '04 Rainier last year. I simply bypassed it since I don't make long trips, and am aware to not use the steering too much to keep the heat down.
The cooler in my '06 Rainier gave out a couple of weeks ago, and I made a cooler out of same size brake line, and used hose to make the return loop at the far end of it.
I use Dexron ATF for fluid because that is what we did back in the day. I have done this with all my vehicles and never had a PS problem because of it.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
In the Saab, I used a small trans cooler to replace the rotted out steering cooler. That's what I'll likely do again unless I find a nice one from the PnP yard, i.e. it was replaced before being scrapped.
 
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Reprise

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Jul 22, 2015
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And one last note on the fluid itself... if it's left there, it won't evaporate on its own. When I freshened up the Sierra's engine, there was P/S fluid clinging to parts all over the undercarriage, from a prior leak (my hydroboost module). Thought it was engine oil, for the longest time. There's probably still a drop or two under there, tbh. So if you're looking for a rust preventative, it could likely do the job.

If the external cooler leaks, just plumb a small, cheap (generic) cooler in, like Moose mentioned. It doesn't need a lot; the area on my Sierra's is about 2" wide x roughly the height of the A/C condenser, which it sits in front of, on the LH side. And that's a HD-spec truck.
If you want to protect the pump & rack from contaminants, consider an inline filter.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Just came back from the PnP yard and scored a cooler. It had been replaced with a Dorman that is made of ALUMINUM. Better rust resistance and heat transfer. Might tackle this on the TB today.

PXL_20211017_161448023_resized6269335058192978645.jpg

So if you need a replacement, either a new or used Dorman is a good option.
 

Mektek

Member
May 2, 2017
656
FL
I had no idea these dorman replacements existed.
Snow chains on the snowblower - scares me to just think of needing such a thing:hahano:
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Snow chains on the snowblower - scares me to just think of needing such a thing:hahano:
That was before they came up with tires with bigger knobs on them. I also have chains on my lawn tractor equipped with a snowblower.

Checked RA and they have three different aftermarket ones which are all aluminum. The Dorman however is the most expensive.

 

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