993 C2 manual - power-steering pump issue

[Ocho]

Hello all

I returned home from a 30 mile (mainly motorway) trip and on reversing onto my drive I noticed that the steering felt very odd - something not right with the feed to the power steering. I've done a little research and given that in recent weeks I had hear some knocking at the rear when reversing (which I put down to the exhaust knocking - now almost certainly wrong) it seems likely that I have something up with either the pump or the belt/tensioner/pulleys. A little more research says that this could potentially have been caused by the collapse of the engine mounts?

Firstly, does this all sound like a fair diagnosis - anything I can do or look for to confirm?

Secondly, how big / expensive is the fix likely to be to fix?

Thirdly, once the fault diagnosis is confirmed, is it safe to drive or would I risk doing a lot more damage?

Thanks as always..

[guards red]

I think your first course of action is checking the power steering fluid level. If its low, and it likely will be, it will need filling up.

If it is low, the fluid has escaped somewhere and thats likely into the track rod arm boots at the front.

However, check the fluid first. If its not low, its possible the power steering belt has broken.

[Ocho]

Thanks - I'll look at that now. Mine's an older one with a clear top to the reservior - anyone know where the marks are as I can't immediately see them?



Also, does the engine need to be warm and running at idle when checking the level? And I found ATF Dexron II on Amazon - is this the correct fluid?

Cheers

EDIT: I've found elsewhere that the two lines around the transparent top are the max and min (pretty obvious really) - there would have been a sticker there indicating them originally but this has long since gone...

Also instead of the Amazon order, I've found this stuff available locally - is it the right fluid?

Edited by Ocho on Wednesday 28th January 12:35

[guards red]

I would use the fluid Porsche recommend which is Pentosin CHF11S or now CHF202. I imagine you can buy equivalents.

The fluid doesn't look low enough to be an issue but worth topping up just in case.

[Ocho]

guards red said:

I would use the fluid Porsche recommend which is Pentosin CHF11S or now CHF202. I imagine you can buy equivalents.

The fluid doesn't look low enough to be an issue but worth topping up just in case.

Thanks. I've just been and checked and you're right, the fluid level is fine, just between the lines. Didn't realise that brown level was the fluid - expecting a clearer oily fluid - is it normally that colour?

So if the fluid level is fine, no leak, which is good, but back to square one with the original problem. Any further thoughts anyone?

[guards red]

The fluid should be a green colour, gets darker with age. That looks really old.

I think you need to be a little clearer in understanding where the problem lies, in the power steering system or elsewhere.

Does the car make noises reversing in a straight line with no steering input or only when steering lock is applied? I think you need to rule the steering out first, if it drives okay and feels even across the locks, it should be okay. Seized ball joints (track rod or lower arm) can cause the rack to struggle. So if it's even and smooth going forward, it may not not be relevant to your issue.

The engine mounts are hydraulic on a C2, i believe rubber on a C4. As the mounts deteriorate the engine drops i the chassis. This can be seen in an increased gap between the exhaust tips and the bumper. However, given the age of the car, this is not a reliable indicator as the tips are adjustable.

[Orangecurry]

Ocho said:

Thanks. I've just been and checked and you're right, the fluid level is fine, just between the lines. Didn't realise that brown level was the fluid - expecting a clearer oily fluid - is it normally that colour?

Life is complicated as always. From memory, so shoot me etc, the earlier cars had the red fluid, and the later had the green.

If it's brown, it means it's too old.

Whilst you are in there, suck out as much as you can with a syringe and a tube, and replace with VAG PAS fluid - it's the same stuff as Porsche sell you but at half the cost. Let me look it up. But GR has the important questions as ususal - more info needed on your actual issue.

Edited by Orangecurry on Wednesday 28th January 17:10

[Orangecurry]

from one of my many spreadsheets.... I believe the fluids are backward compatible? But I have a MY96 and I've used G004000M2 to flush and replace. When I bought the car, the existing fluid was pale green but with a very fine particulate in suspension.

PAS fluids
Pentosin CHF11S is G002000 (VAG) and Pentosin CHF202 is G004000M2 (VAG)
Pentosin https://crpautomotive.com/brands/pentosin/hydrauli...
CHF 11S
CHF 202
G 004 000 M2. Density at 20degC 0.83 g/cm3
Kinematic viscosity 19 mm2/s 40degC

Edited by Orangecurry on Wednesday 28th January 17:19

[Ocho]

guards red said:

The fluid should be a green colour, gets darker with age. That looks really old.

I think you need to be a little clearer in understanding where the problem lies, in the power steering system or elsewhere.

Does the car make noises reversing in a straight line with no steering input or only when steering lock is applied? I think you need to rule the steering out first, if it drives okay and feels even across the locks, it should be okay. Seized ball joints (track rod or lower arm) can cause the rack to struggle. So if it's even and smooth going forward, it may not not be relevant to your issue.

The engine mounts are hydraulic on a C2, i believe rubber on a C4. As the mounts deteriorate the engine drops i the chassis. This can be seen in an increased gap between the exhaust tips and the bumper. However, given the age of the car, this is not a reliable indicator as the tips are adjustable.

OK, so here's the full picture. Over the last couple of weeks, I have noticed a rattling noise when coming out of and reversing back into the garage, which is always done on full steering lock. I have had the exhaust off fairly recently and so put this down to refitting not quite perfectly as it's always sat very close to the valence surrounding it (if that's the right word for it!) and vibrating at lower revs at this point.

When I got back home from the journey as mentioned, I got out of the car to manually open the gate - car left idling whilst I go and do this - and I heard a quietish knocking sound from the rear of the car. Thought initially that it was the same exhaust vibration (the one that never was) although it was quieter, so stopped under the car for a listen and it was clearly not exhaust on bodywork but a very regular knocking sound that tallied with the low revs of the engine at idle. When I then moved the car to reverse onto the driveway and round into the garage (hard left turn) I could feel that something was up with the steering - power steering not quite doing it's job properly. As I turned the wheel, the assistance was sort of on/off through the turn. Haven't driven it since.

Anything else you need to know just ask. It's a high mileage C2 manual pre-varioram.

[Orangecurry]

Have you seen your wife recently?

[Ocho]

Orangecurry said:

from one of my many spreadsheets.... I believe the fluids are backward compatible? But I have a MY96 and I've used G004000M2 to flush and replace. When I bought the car, the existing fluid was pale green but with a very fine particulate in suspension.

PAS fluids
Pentosin CHF11S is G002000 (VAG) and Pentosin CHF202 is G004000M2 (VAG)
Pentosin https://crpautomotive.com/brands/pentosin/hydrauli...
CHF 11S
CHF 202
G 004 000 M2. Density at 20degC 0.83 g/cm3
Kinematic viscosity 19 mm2/s 40degC

Edited by Orangecurry on Wednesday 28th January 17:19

Thanks as always OJ. The level of detail is as expected.

I've ordered some CHF 11S which should arrive tomorrow, but whilst I will take your advice re a clean and replace as best I can with that, I suspect it's not the problem in this case with the levels being fine, unless being brown (I'll take a photo of the contents tomorrow in daylight) means it's actually not doing it's job anymore?

[Orangecurry]

Ocho said:

a very regular knocking sound that tallied with the low revs of the engine at idle.

Hydraulic lifter?

[Ocho]

Orangecurry said:

Have you seen your wife recently?

Err, what??? I'm not sure I get you

[Ocho]

Orangecurry said:

Hydraulic lifter?

Fair observation, but I don't think so - different sound I think.

[Orangecurry]

it's my sense of humour

Ocho said:

OK, so here's the full picture. Over the last couple of weeks, I have noticed a rattling noise when coming out of and reversing back into the garage, (wife).

When I got back home from the journey as mentioned, I got out of the car to manually open the gate - car left idling whilst I go and do this - and I heard a quietish knocking sound from the rear of the car.
(run over wife)

When I then moved the car to reverse onto the driveway and round into the garage (hard left turn) I could feel that something was up with the steering - power steering not quite doing it's job properly. As I turned the wheel, the assistance was sort of on/off through the turn. Haven't driven it since.
(wife jammed in steering)

I imagine that you have rattley heat shields and a rattley hydraulic lifter. You may also have an issue with the PAS.

[Ocho]

Firstly, re wife, very good now explained...

Orangecurry said:

I imagine that you have rattley heat shields and a rattley hydraulic lifter. You may also have an issue with the PAS.

Seems a bit coincidental to me that the noise started with the steering issue. The noise at idle whilst opening the gates was not something I have heard before and came on absolutely when the steering issue started, so I'm thinking something to do with the power steering belt/tensioner/pulleys...

[Orangecurry]

I've just changed the PAS pump on my Subaru flat-six, so my brain is full of how that works/AUX belt idlers/tensioner, and can't even visualise the 993 system - sorry.

Listen to whatever GR says - he is the clever one.

[guards red]

Why thank you, I'm blushing! I'm often told I'm full of sh*t so it's nice that can can pretend otherwise.

The first and most important thing to do is make sure the engine is okay, and that is largely limited to making sure it has oil in it and good oil pressure. That it's at least around 1bar with the engine hot and at idle. If it is, and you're happy its not the engine making the noise, you can sigh a sigh of relief. Anything related to the engine can get horribly expensive.

The power steering pump can fail, but it's not a common issue. If the steering power assistance is spasmodic, and the records show the belt has never been changed I'd look into that first. The belts are like a thicker, shorter cam belt. They can strip their teeth. Especially in very cold weather. They are however not easy to inspect or change. There is a tiny gap near the back of the engine tin that allows one to see a very small section. But you would need for someone to spin the engine by hand for the check to be meaningful. From memory its best seen in the wheel well. The cover is very difficult to remove, though its possible to remove the lower cover bolts and use a camera to check it by flexing the plastic a little. I would start there.