Advice please - oil in water
12-29-2014, 10:42 PM
#1
Advice please - oil in water
Hi all
I bought a 1989 S4 in the summer which I'm chuffed with. The seller highlighted the fact that there was some, as he said, residual oil in the coolant system as he'd just had the radiator re-cored as the oil cooler was leaking into the water, and a flush hadn't got rid of it. We struck a good deal though and I knew I was taking a chance.
Well, 2 more coolant changes and 3,500 miles later there's still emulsion in the coolant tank.
Oil consumption is high (~ 1 litre/6-800 fairly fast miles VR1 20w50)
Oil seems clean
The engine is on 144,100 miles with good service history and pulls well
Car doesn't smoke or overheat (the water temp needle is just below the second bar i.e. past half way but stable in traffic and hard running. It falls very slightly on an unstressed cruise but still past the half way)
Oil sump gasket has a seep but not enough to leave oil drops on garage floor
So, any advice chaps? I'm thinking either the radiator re-core was unsuccessful and there's a small leak of oil to water still or I need some way of getting old crud out - would like to know a sound method of doing this before I shell out on new coolant hoses and bottle etc. Doesn't feel like a head or head gasket but I am not expert.
Cheers
Mark
I bought a 1989 S4 in the summer which I'm chuffed with. The seller highlighted the fact that there was some, as he said, residual oil in the coolant system as he'd just had the radiator re-cored as the oil cooler was leaking into the water, and a flush hadn't got rid of it. We struck a good deal though and I knew I was taking a chance.
Well, 2 more coolant changes and 3,500 miles later there's still emulsion in the coolant tank.
Oil consumption is high (~ 1 litre/6-800 fairly fast miles VR1 20w50)
Oil seems clean
The engine is on 144,100 miles with good service history and pulls well
Car doesn't smoke or overheat (the water temp needle is just below the second bar i.e. past half way but stable in traffic and hard running. It falls very slightly on an unstressed cruise but still past the half way)
Oil sump gasket has a seep but not enough to leave oil drops on garage floor
So, any advice chaps? I'm thinking either the radiator re-core was unsuccessful and there's a small leak of oil to water still or I need some way of getting old crud out - would like to know a sound method of doing this before I shell out on new coolant hoses and bottle etc. Doesn't feel like a head or head gasket but I am not expert.
Cheers
Mark
12-29-2014, 11:37 PM
#2
Just had the same thing, Oil cooler is in the water jacket, and it is leaking. If you think it is fixed, put some dishwasher powder in the coolant system, and let it do its magic. You will have to drain the coolant, including the block. there is a drain plug at the back of the engine block.
With the high oil consumption, looks like you still have a leak. You can pull the radiator when you drain the coolant system and have it tested...
Good luck, I am replacing my radiator with and AL one.
With the high oil consumption, looks like you still have a leak. You can pull the radiator when you drain the coolant system and have it tested...
Good luck, I am replacing my radiator with and AL one.
12-30-2014, 01:07 AM
#5
Rennlist Member
Mark,
Seems pretty clear the leak path into the radiator is not sealed- I assume from the tenor of your post that your model still has the in tank engine oil cooler on the driver's side? - eliminated on the later S4/GTS's like mine. Short of removing the radiator and carrying out a leak/pressure test on the in tank cooler coil you can do no more. From your description I would think a blown head gasket is not the likely culprit at this stage.
I would not call your oil consumption "excessive" for a hard driven S4 given my long term experience with this motor- not that I endorse or welcome such consumption rates. There appears to be a magic rpm number [circa 4k rpm] wherein the motor starts to use noticeably more oil presumably down to its notorious oil lifting issues at higher rpm's. Thus why many folks like myself have played around with the engine breathing to try and reduce the oil consumption and support the effective octane rating of the fuel [excessive oil running through the combustion chamber reduces such]. Thus I suspect that most who have stock setups and use little oil do so because their motors are not worked but to be clear there does appear to be quite a lot of variation from example to example. Porche tell you in the owners handbook that the engine consumes something rediculous like a litre every 500km.
To be clear, I do not rule out engine oil migrating into the cooling circuit but if it was in such quantities your header tank would fill up and you would be blowing the resulting coolant/oil emulsion on the deck via the breather cap/engine bay & that would be very messy/noticeable indeed I would suggest.
Regards
Fred
Seems pretty clear the leak path into the radiator is not sealed- I assume from the tenor of your post that your model still has the in tank engine oil cooler on the driver's side? - eliminated on the later S4/GTS's like mine. Short of removing the radiator and carrying out a leak/pressure test on the in tank cooler coil you can do no more. From your description I would think a blown head gasket is not the likely culprit at this stage.
I would not call your oil consumption "excessive" for a hard driven S4 given my long term experience with this motor- not that I endorse or welcome such consumption rates. There appears to be a magic rpm number [circa 4k rpm] wherein the motor starts to use noticeably more oil presumably down to its notorious oil lifting issues at higher rpm's. Thus why many folks like myself have played around with the engine breathing to try and reduce the oil consumption and support the effective octane rating of the fuel [excessive oil running through the combustion chamber reduces such]. Thus I suspect that most who have stock setups and use little oil do so because their motors are not worked but to be clear there does appear to be quite a lot of variation from example to example. Porche tell you in the owners handbook that the engine consumes something rediculous like a litre every 500km.
To be clear, I do not rule out engine oil migrating into the cooling circuit but if it was in such quantities your header tank would fill up and you would be blowing the resulting coolant/oil emulsion on the deck via the breather cap/engine bay & that would be very messy/noticeable indeed I would suggest.
Regards
Fred
12-30-2014, 07:58 AM
#6
Just had the same thing, Oil cooler is in the water jacket, and it is leaking. If you think it is fixed, put some dishwasher powder in the coolant system, and let it do its magic. You will have to drain the coolant, including the block. there is a drain plug at the back of the engine block.
With the high oil consumption, looks like you still have a leak. You can pull the radiator when you drain the coolant system and have it tested...
Good luck, I am replacing my radiator with and AL one.
With the high oil consumption, looks like you still have a leak. You can pull the radiator when you drain the coolant system and have it tested...
Good luck, I am replacing my radiator with and AL one.
12-30-2014, 08:03 AM
#7
Mark,
Seems pretty clear the leak path into the radiator is not sealed- I assume from the tenor of your post that your model still has the in tank engine oil cooler on the driver's side? - eliminated on the later S4/GTS's like mine. Short of removing the radiator and carrying out a leak/pressure test on the in tank cooler coil you can do no more. From your description I would think a blown head gasket is not the likely culprit at this stage.
I would not call your oil consumption "excessive" for a hard driven S4 given my long term experience with this motor- not that I endorse or welcome such consumption rates. There appears to be a magic rpm number [circa 4k rpm] wherein the motor starts to use noticeably more oil presumably down to its notorious oil lifting issues at higher rpm's. Thus why many folks like myself have played around with the engine breathing to try and reduce the oil consumption and support the effective octane rating of the fuel [excessive oil running through the combustion chamber reduces such]. Thus I suspect that most who have stock setups and use little oil do so because their motors are not worked but to be clear there does appear to be quite a lot of variation from example to example. Porche tell you in the owners handbook that the engine consumes something rediculous like a litre every 500km.
To be clear, I do not rule out engine oil migrating into the cooling circuit but if it was in such quantities your header tank would fill up and you would be blowing the resulting coolant/oil emulsion on the deck via the breather cap/engine bay & that would be very messy/noticeable indeed I would suggest.
Regards
Fred
Seems pretty clear the leak path into the radiator is not sealed- I assume from the tenor of your post that your model still has the in tank engine oil cooler on the driver's side? - eliminated on the later S4/GTS's like mine. Short of removing the radiator and carrying out a leak/pressure test on the in tank cooler coil you can do no more. From your description I would think a blown head gasket is not the likely culprit at this stage.
I would not call your oil consumption "excessive" for a hard driven S4 given my long term experience with this motor- not that I endorse or welcome such consumption rates. There appears to be a magic rpm number [circa 4k rpm] wherein the motor starts to use noticeably more oil presumably down to its notorious oil lifting issues at higher rpm's. Thus why many folks like myself have played around with the engine breathing to try and reduce the oil consumption and support the effective octane rating of the fuel [excessive oil running through the combustion chamber reduces such]. Thus I suspect that most who have stock setups and use little oil do so because their motors are not worked but to be clear there does appear to be quite a lot of variation from example to example. Porche tell you in the owners handbook that the engine consumes something rediculous like a litre every 500km.
To be clear, I do not rule out engine oil migrating into the cooling circuit but if it was in such quantities your header tank would fill up and you would be blowing the resulting coolant/oil emulsion on the deck via the breather cap/engine bay & that would be very messy/noticeable indeed I would suggest.
Regards
Fred
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12-30-2014, 09:40 AM
#8
Rennlist Member
The other approach is to simply pressurise and see if it holds the pressure but with a pneumatic test it can take a long time to lose pressure if the leakage rate is very small [as will likely be the case].
Just to complicate things I suppose there is always the possibility that the leak only becomes noticeable or significant when everything expands in the operating [hot] condition. The best thing would be to take it to a specialist [proven] radiator shop and let them test it for you.If they are half decent they will not charge you as it gives them a chance to quote for a repair. No idea if that is even viable with a plastic end tank.
Regards
Fred
12-30-2014, 05:17 PM
#9
I went on about a 20 mile drive, got it up to temp with the powder in there. Did not seem to effect the cooling system at all. and I did drink the entire system... Radiator and Both sides of the block.