Power steering fluid is overflowing in 2002 S40

Fosgate · Post by **Fosgate** » 24 Nov 2020, 19:00

Hey guys,

So we have this issue with out 2002 S40, after driving for a while (30-40mins) the power steering fluid seem to bubble (or maybe boil) and it starts overflowing from the reservoir. The whole power steering system starts making whining noise when you turn the steering wheel in either direction. One thing to note is that I had to remove the mesh filter from the reservoir as one of its sections was disintegrated and I thought I better remove the rest before it sent more pieces into the system. Not sure if the missing piece from the filter or even not having the filter at all could cause this.
Initially I thought the problem was with the feedline (from the reservoir to the pump) that was sucking air in so I replace the clumps, took the car for a short drive and everything seem to be fine, however this morning I had to go for a longer drive and by the time I got to my destination (45mins away) the Power steering was again making the whining noise and again the fluid has overflown from the reservoir all over the engine bay (Right side).
Also to note when this happened first time most of the fluid was gone so I filled it up with ATF/Power steering fluid not knowing that these cars use special type of fluid CHF11 rather than your average ATF.
I searched the forum and read that few people had similar issue but I couldn't find clear post on what solved the issue. Some people recon they replaced the fluid with correct CHF11 type and other recon it could of been the pump or the feedline going to the pump leaking air internally. I would of assumed I did have the correct fluid to start with when this happened initially so not sure how replacing the fluid would help but might need to give it a go.
Any advise would be greatly appropriated.

Thanks

Post by **alschnertz** » 26 Nov 2020, 06:27

May be a dumb question, but you are reading the fluid level according to the dipstick, right?
I generally check the level when the fluid is hot.
To me, it seems like even when "full", the level is pretty low in the reservoir on my '01.

FWIW, I've always used ATF (no particular type) to fill or top up.

Fosgate · Post by **Fosgate** » 26 Nov 2020, 19:12

Thanks for your reply,
Yes using the deepstick to check the levels. I believe the series 1 S40 you could use ATF but in series 2 they recommend special hydrolic fluid CHF11 or CHF202.
I guess my main concern is the bubbling/boiling that pushes the fluid out.

Post by **alschnertz** » 27 Nov 2020, 08:22

I doubt the fluid is "boiling' as I'd imagine the boiling point temperature is quite high.
That makes me think it's more likely a pressure issue since you said the level is correct.

Then again, maybe those missing pieces of filter are stuck in the pump somewhere and creating the whining noise.

Wish I could help, but just don't know enough specifics about the power steering system and haven't had issues with mine...yet.

Fosgate · Post by **Fosgate** » 06 Dec 2020, 16:39

Just to give everyone an update incase you are having the same issue.
I have drained the old fluid from the power steering system, installed a new filter in the reservoir, replaced the factory clumps on the pick up hose with some aftermarket ones that can be tightened properly, filled up the system with some CHF202/11 fluid and the problem has now been fixed. I have driven the car for a good 30kms now and everything looks pretty good so far, no bubbles in the system or overflowing.
I suspect the filter that inside the reservoir plays a bigger role then keep the dirt away when filling up the system, also with time the clumps holding the pick up hose loosen themselves thus sucking in an air into the fluid going to the pump, and lastly it seems like as this PS setup requires a specific PS fluid rather then your average ATF.

Post by **MoVolvos** » 06 Dec 2020, 18:28

Fosgate wrote: ↑06 Dec 2020, 16:39 Just to give everyone an update incase you are having the same issue.
I have drained the old fluid from the power steering system, installed a new filter in the reservoir, replaced the factory clumps on the pick up hose with some aftermarket ones that can be tightened properly, filled up the system with some CHF202/11 fluid and the problem has now been fixed. I have driven the car for a good 30kms now and everything looks pretty good so far, no bubbles in the system or overflowing.
I suspect the filter that inside the reservoir plays a bigger role then keep the dirt away when filling up the system, also with time the clumps holding the pick up hose loosen themselves thus sucking in an air into the fluid going to the pump, and lastly it seems like as this PS setup requires a specific PS fluid rather then your average ATF.

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Your issue was not the fluid. Volvo does not produce their own fluids so an OE equivalent should work. I use to purchase Honda or equivalent power steering and transmission fluids against my better experience. Over the course of ownership of the 03 Odyssey from 154K to 230K I've settled on a good synthetic or regular transmission fluid in both systems and have not had a problem.

The 712 stock I have is old so it's not synthetic. Too costly now but it's in the PS reservoir and had been in 3 other 2000 ~ 2004 Odyssey transmissions, mine 4th without issues.

https://www.amazon.com/712-Heavy-Duty-M ... 556&sr=8-1

Super low price on a case of 12 at $46.49 & FREE Shipping. 03 GS300 (Trans, PS), 03 S80 T6 (Trans, PS) & 03 Odyssey (Trans)

https://www.amazon.com/HAVOLINE-2265364 ... 165&sr=8-1

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