Thread: Oil Leak 3.0L D4 - Oil cooler and filter assembly -should it have a hole here!

Whilst I don't subscribe to the cavity expanding air aspect, having a tell-tale hole that weeps coolant or oil would be by design and would necessitate a common cavity.

Is not a replacement gasket available? One is for the 2.7's and 4.4's coolers so I would expect one for the 3.0's cooler too.

Had a marine engine with a PTO engine driven raw water impeller pump with same principle. Weep hole if oil coming out shaft seal to engine side gear drive failed. Sea water coming out shaft seal to salt water pump had failed.

Well I changed my oil cooler today on my D4 3L. Not the easiest of jobs. As I think Justin advised, I had to trim the intake manifold to get it out. Thanks Justin for that tip else I’d probably have either cried (more) or done something more drastic. Got it back together and thought I’d completely screwed the car. Started up and there a god awful intermittent screech. I think it was the water pump as the cooling system was running low and needed bleeding and topping - not sure - but feared the worst. Also as advised I drained the oil to rid it of any coolant. Interestingly I also drained via the sump after vacuuming it out. I got about 10ml out additionally so vacuum extraction is pretty good! I did run through a litre of fresh oil top to bottom to try and flush out any residual coolant trapped in the sump. Very little in the end. I was pretty careful and taped up everything as soon as I could.

Don’t think it was my leak source. I think I’m just going to fork out the cash and get it body off and find all the leaks and fix it once and for all.
265,000km and still a (wet/oily) dream of a car.

Originally Posted by disco4now

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How was the gasket - had it gone hard?

Hi Graeme. I didn’t strip down the oil cooler as yet. I replaced the entire unit top to bottom. The o-rings that interface the block were pretty flat but I think they still had a seal, hence I don’t think it was my problem

Originally Posted by DiscoJeffster

Started up and there a god awful intermittent screech. I think it was the water pump as the cooling system was running low and needed bleeding and topping - not sure - but feared the worst.

Know how you feel, DJ, I had the same when I changed out the coolant last December. Once bled and topped up all ok. Sorry to hear that the cooler is not the source of the oil leaks, hope you get that sorted.

So picks of the cooler disassembled. Interesting muck build up on the coolant channels

Thanks DJ. Interesting that there does not appear to be any "tracking" from the oil side to the inspection hole. Have you noticed oil in the coolant at all?