Sudden catastrophic engine oil leak

[zcacogp]

Chaps,

Quickie.

On the way back home this morning it seems that my S2 has developed a sudden and catastrophic oil leak. About 100 yards away from home, at some traffic lights, there was a smell of hot oil. Engine temperature was fine as was the oil pressure, so I drove the last 100 yards very carefully and turned the engine off. Under-bonnet inspection showed there to be oil thrown around the engine bay from the belts on the front of the engine (fan / PAS). I didn't investigate further as I didn't have time and the engine was wet thus disguising where the oil was.

There was also a very noticeable trail of oil down the road (oil on wet road = rainbow patterns.)

I won't be able to look at the car for a couple of days (thankfully I don't need to drive it), but what is likely to fail to cause this? Sudden failure, of a pressurised oilway, somewhere such that oil escapes onto the belts at the front of the engine (possibly indirectly - i.e. spraying onto something else and then dripping off onto the belts.) What is likely to have caused this failure and where should I be looking?

Engine oil pressure didn't drop (although I expect there won't be much left in the sump). Car is regularly serviced, last done about 4,000 miles ago.

All suggestions welcome, thanks.


Oli.

 

[Mike_Pollock]

Sure its engine oil?

Thinking PAS fluid, as I cant think where engine oil is likely to come from like that.

 

[Cater_Racer]

Hi Oli,

Could be the oil cooler? or one of the pipes to it?

Gerry

 

[Mike_Pollock]

Ah - good call Gerry, forgot S2s have external oil coolers.....

 

[colin944]

I would go for oil-cooler seals. Have you bumped the front of the car.The cooler sits low down on the drivers side and can be bumped via its cold air intake.Or the rubbers that hold it in place could have given up and put strain on the joints. If not that then something like balance shaft oil seal.
However I'm confident you will find it Oli and that it will turn out to be something rubber based.

 

[ALZ 1933]

Check it's not the seal on the oil filter that's given up. This happened to a friends 944 & resulted in the full car being broken for spares.

 

[944 man]

Front crank seal matches the end result, although Id have expected it to have been leaking for a while.

 

[simkin911]

Sorry to hear this Oli. Good luck with the investigative work.

 

[JamesO]

A sticking oil pressure relief valve can cause this (seen first hand) and blow out the oil filter seal although the dash gauge will read high assuming its working properly.

 

[zcacogp]

Chaps,

Thanks for your answers. I have had no more time to have a look at the situation, and it's now dark so working time is over (I work on the car by the side of the road, which isn't ideal.)

Suggestions:

Mike, thanks. I'll check. It'll be easy to do; there has been a LARGE leak of fluid, and it was PAS fluid then the reservoir will be empty. Good idea. (Although I think it's oil).

Gerry/Mike/Colin - VERY good idea. The car hasn't had a knock to the front that I am aware if (it hadn't had one immediately before the failure if that's the question) and hence I'll go looking there. I guess that the seals are pretty easy to change once the oil cooler has been dug out. What's the best way of doing this? Batwing off and go from there?

Alan/James, good idea, but I don't think it is (will still check tho'). The oil filter seal is a bit behind the belts and was the only thing I had a (very quick) look at when I opened the bonnet. Would be nice if it is this tho', as it's an easy fix. However, if it is, I will need to find out why it popped (oil pressure relief valve or something else - thanks James.)

Simon, front crank seal was changed about 12-18 months ago, but that's not to say the new seal hasn't gone pop as well. I don't think it was leaking tho'.

Steve - thanks for your good wishes.


Oli.

 

[SUSIT]

sounds more like an oil cooler issue to me, perhaps a pipe might only get it to leak when engine run as needs pressure, good luck with finding it, working on the street this time of year not the best of fun.

 

[zcacogp]

Steve, thanks. You're right in every aspect of your post; it's the oil cooler hose, fretted through on the underneath of the PAS pipe. Hole big enough to put your finger in.

Now I'm worried that about 4 minutes of driving without any oil in the sump (it was empty) will have knackered the engine! Mind you, the oil pressure gauge remained at 5bar and no warning light came on.

Now fighting with the 32mm spanner on the end nut of the rearmost hose fitting. It's a pig to get to, even with undertray, batwing and ARB off! I don't want to have to drop the steering rack as that will mean a geo re-align, which I'd like to avoid.

(Oh and Steve, you are also right in saying it's not a good time to be working outside. I've just been alternately snowed on, rained on and had oil dribbled on me!)


Oli.

 

[JamesO]

ORIGINAL: zcacogp


Now fighting with the 32mm spanner on the end nut of the rearmost hose fitting.




Oli.

I thought you had an S2? The S2 hoses I've seen use a plate type fitting with one central 13mm? bolt in the middle. Have you secretly upgraded to a turbo and kept it quiet?

 

[Hilux]

ORIGINAL: zcacogp

Now I'm worried that about 4 minutes of driving without any oil in the sump (it was empty) will have knackered the engine! Mind you, the oil pressure gauge remained at 5bar and no warning light came on.

Oli.

Did the engine go all top end clattery - it would with catastrophic pressure loss as its the high pressure end of the system.

Also big ends can take very low pressure and be undamaged (at moderate revs) as low as as 2 or 3 psi - warning lights commonly come on around 5 psi (ish) on cars of that era.

Note: Is the oil cooler supplied via a temperature regulator ie: only opens up when the oil is warm? If so thats why the pressure didnt drop, has probably saved your engine and is probably therefore contents of the cooler only.

If not then you sounds like you got away with it (hopefully) but fingers crossed for you.

A great big red f*ck off light or buzzer you cant miss warns you when the pressure gets low as you dont normally sit and watch the gauge. Saved my Golf`s engine on track.

 

[zcacogp]

James - wash your mouth out, young man! No, I have NOT bought one of those blower things! The connections of the oil cooler hoses at the engine end are 32mm nuts, around the circumference of the hoses. They are positioned such that getting a spanner on them isn't that hard, but turning that spanner is very difficult. I have ordered a (cheap) 32mm spanner this afternoon to allow me to cut it down to get the hoses off.

Paul,

Thanks. No, the whole engine sounded (and ran) fine - so fine, in fact, that I wondered whether the strong smell of hot oil was to do with some other car. Having said that, when I started it today (after having half-filled the sump with clean oil) to try and find the leak it did sound quite clattery, but that was definitely from the front and not the top. And that was with the front of the car in the air with all the trays off, so it will sound quite different.

The exact flow of oil, as you ask, is a very good question. The Clark's Garage diagram suggests that oil flows 'round the cooler all the time, but it also suggests that the oil pressure release valve bypasses the engine galleries in a strange way, so I'm not sure that I understand it exactly. (It does, however, suggest that the oil pressure sensor shows pressure after the oil cooler, in which case then I probably am in the clear as the gauge never showed less than 5 Bar - I watched it like a hawk once i had smelled the hot oil smell.)

I'll keep this thread updated. Job for tomorrow (if I can find the time) is to find a local hydraulic hose specialist who can either make up a new hose for me or re-make my existing hose for less than the £260 or so that they seem to sell for on-line. I haven't dared call Porsche to ask for the price from them ... []


Oli.

 

[JamesO]

Ahh yes maybe me being stupid, the 968 oil cooler housing has the same connections as the S2 oil cooler (if that make sense). Although maybe Your S2 is lucky enough to have some turbo parts on it.....
Worth trying OPC, you may or may not be surprised. They were cheapest for power steering hoses a while back.

ETA

Looking at the parts diagrams it seems I am being stupid in assuming the S2 and 968 have the same housing.

 

[chrisg]

Oli

reference having the pipe remade as explained I've had many of my pipes on the turbo converted across to SS braided hose. A good quality hydraulic pipe manufacturer will use the existing pressure fittings/ couplings and just replace the pipe itself. I'd be very surprised if Pirtek or a n other local company can't refurb the offending pipe for less than a new one from OPC.

If you get really stuck, speak to Paul Rutter at spectrum hose in High Wycombe:

http://www.spectrum-hose.co.uk/

01494 524332

Chris

 

[edh]

I think that diagram applies to the 8v 944 which has a small oil / water cooler.

the turbo has an external oil / air cooler on a thermostat. from my experience it's not fully closed off when cold, but has much reduced flow, with most oil bypassing that circuit.

I would have thought the s2 was the same.

 

[zcacogp]

ORIGINAL: edh
I think that diagram applies to the 8v 944 which has a small oil / water cooler.

I think that diagram applies to the turbo. In fact, there is a clue in the diagram itself - I wonder whether you can spot it? []

How the S2 is laid out is possibly a different matter, but given that all 944's are largely the same in terms of layout and things like belts, coolant, positioning of oil filter and so on then I'd guess it is the same.


Oli.

 

[zcacogp]

Slight update; I've ordered another 32mm spanner (cheap, made by silverline) which should arrive tomorrow, which I'll cut down to allow me to remove the hose in question. My current spanner is too long to be any use in the confined spare in question, but to good to attack with an angle grinder.

I've spoken to the local Pirtek who were very helpful indeed. They said they should be able to make me a new hose or replace the hose part of the existing part, the only question is whether they will be able to do it in one of their vans (which carry limited kit) or whether I will need to take it into a service centre.

I'll try and find the time to jetwash all around the affected area later on today; it's covered in old grot and new oil, and it's nasty. Working on clean cars is much nicer than working on dirty ones. Thankfully it's not snowing today.

The various nuts and bolts and screws I have taken off thus far are all swimming around in some caustic soda fluid in an ultrasonic cleaning bath and will look as good as new when they come out.

More updates in due course.


Oli.