I have had a 1997 Audi A4 1.8 SE (ADR 20V engine) for seven trouble-free years and 120,000 miles until earlier this year when it started using water but in fairly small quantities (1 pint in 500 miles). This continued for several months while I tried to work out whether I had a coolant leak or a head gasket problem. Suddenly the problem worsened when oil started entering the coolant and collecting in the expansion tank (1 pint in 50 miles). I had it checked an my local garage who confirmed that it was the head gasket as they found exhaust gases in the coolant as well. Having had a lot of experience re-building engines in the past, I decided to replace the head gasket myself along with the water pump, cam belt, roller and tensioner. I used Audi parts and new head bolts as recommended by my local dealer. The odd thing was that old gasket seemed fine and the head/block surfaces were flat and undamaged but I replaced the gasket as planned. To my shock, within a few miles I realised that the problem as just as bad. I flushed the coolant system and re-tested it but oil was still entering the coolant at the same rate. I am now worried that the head may be cracked or the block corroded between the water and oil ways but don't don't know how to identify the problem without massive dealer bills. Have you heard of similar poblems or do these Audi engines have a history of this? Can you suggest any ideas to help me identify the cause of the problem?
Thanks,
Duncan Poxon
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Does the car have a oil / water heat exchanger sandwiched between the oil filter and the engine block? These are known to leak internally and cause mixing ;-)
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If you are sure you have done the head job properly and the head/block are flat then its sounds like a crack. Whatever you do it won't be cheap to fix......
BTW - it always pays to have the head skimmed and pressure-tested when doing a HG replacement. £60.
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Yes with hindsight I agree I should have had it tested. Where can I get pressure testing done? Presumably not at an audi dealer?
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Thanks for the suggestion - I'll have a look tonight. What function does this perform? It has an oil cooler rad at the front but this heat exchanger sounds different??
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Thanks for the suggestion - I'll have a look tonight. What function does this perform? It has an oil cooler rad at the front but this heat exchanger sounds different??
We're talking about the same thing just adifferent name.
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I had a similar experience with a 1.8 PB engine. Oil in coolant at 80,000 miles. Took head off. Noted that head bolts were not very tight.
Re-fitted head with new bolts, gasket etc. Problem persisted - oil in coolant. Without removing head, slackened bolts off and then re-tightened extra tight. Problem cured. However, In view of forthcoming trip to south of france, I decided to do the job again. First got my torque wrench recalibrated and found it had been about 9% low. New gasket and bolts, a smear of Hylomar Blue around the oil-way and tightened very carefully making sure to achieve the full torque readings and the full angle turns specified. Subsequently, the engine ran to 260,000 miles without gasket/oil/coolant problems.
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