Oil Cooler Woes ( Oil in coolant)

[trebor]

Well recently on checking my coolant level on my 75 Diesel I discovered lots of oil mixed with water on the header tank cap




Car has done 196, 000, but as failure of head gaskets are unheard of with this engine, surely there has to be another explanation.

Thanks to Arctic for pointing me in the direction of the oil cooler as that is what myself and Steve (Devilish) tackled recently, it sits at the front of the engine and has 1 coolant pipe entering it.


There are 2 gaskets that can be replaced the one on the oil cooler itself and another that sits behind the cylinder block and the oil filter adapter



First of all had to drain the coolant to find this, where oil had got into the coolant and was forming in globules, note the sludge dripping out of the bottom hose




I then flushed the system first of all with Holts which wasn’t very effective as the oil was still separate from the water and I needed it to mix as there was a lot of sludge at various places including the in line stat which I removed cleaned and have left out for now. So changed to Wynne’s System flush and much better as oil mixed with coolant and came out as one dark liquid.

Next step was to change the oil cooler gasket and had to remove the starter motor to get at one of the oil cooler bolts so put a refurb kit in the starter whilst it was out.

At the time I didn’t change the other gasket as hadn’t got one at that stage and it also looks like one of the bolts to come out is sitting beneath the alternator.

So since then I have kept changing the water and each time there has been less and less oil in it as hopefully the gasket has solved the problem and I am just getting rid of what was already in there, I haven’t yet put any coolant in it until I know I have solved the problem so just running the car at the moment and keeping an eye on the situation.

There are a few historical posts on the forum relating to the oil cooler (John – Number 6 for one ) but not many so please share your experience if you have some knowledge to pass on, and if you have had to do the job did 1 gasket solve the problem or did you need both ?

I will update this thread as and when I make more progress and solve the problem.

I have also had to have a clutch recently but that’s on another thread.

[Arctic]

Hi Rob.
Nice to see you have posted the problem it will help others in the future, all you can do is keep changing the water every week or 2wks maybe use blue coolant for a while before you go back to the OAT, but that could be the reason behind the failing seals ? who knows.

Come spring i may just change out the two seals as a preventive measure.

1

I have a spare i could get ready to swap it out.
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Just so the readers/members know here is where the oil cooler and oil filter pot is on the car.
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Three torx to remove the cooler on it's own, one at the top two under at each end.
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To remove the cooler and oil filter pot as one unit you have three bolts and one bolt for the oil dip stick.

Oil dip stick bolt.
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Which allows you to remove the dip stick tube from the sump.
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Remove the three bolts holding the oil filter pot to the engine
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Removed from the car engine as an whole unit.
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The small gasket between the cooler and the pot.
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PS we may have to do some virtual meets on the Nano, people can ask which is best way to do a certain job, and we could answer, maybe sort out some virtual meet dates when we can be around to answer?

[macafee2]

thank you for this post, if I had found oil in the coolant I would have collapsed with shock. At least now I will look at the gasket you mention.


I don't recall seeing a thread about a diesel having oil in the water so is this a very rare event?


macafee2

[trebor]

It is rare yes but as our cars do more and more miles and are kept on the road it may become more common.

Thanks to Steve for posting the pictures

[janker]

Thanks for taking the time to post and something to keep a lookout for.

[Mike Noc]

Originally Posted by trebor

It is rare yes but as our cars do more and more miles and are kept on the road it may become more common.

Thanks to Steve for posting the pictures

Did you pressure test the heat exchanger Rob, or could you see that the gasket was leaking?

[bl52krz]

Hi Rob. Were there no signs being given off that something was amiss?
No high temps or on checking the dipstick! Oil consumption? Let’s hope you have caught it before it causes any long term effects.

[Mickyboy]

Been there recently, Tesco value washing powder is great for cleaning all the hoses
Mick

[It runs]

When the oil cooler failed on my previous one it wasn't the gasket.
The oil cooler had developed a small leak internally and the oil was passing into the water from inside the cooler.
When it was removed I cleaned it and put air pressure through the water hose fitment and blocked the other end I held in a bucket of water and I could see small bubbles coming from the oil side.
Took ages to clean I used ( and I am not saying you should)
A few caps of non foaming carpet cleaner.
Downside of lots of oil in the water . And their is never a good side by the way
Is this . You may start having water hose failure.
The oil damages the hoses from the internal heat mixed with the water.
Mine was plauged with it right upto me (scrapping the car)
That's not why I scrapped it but it was a deciding factor at mot time when it needed a brake pipe /wishbones and a couple of other bits, as it was only a matter of time before I had a leak behind the dash.
I did have a serious amount of oil in the water by the way so don't panic.
It was a great opportunity to get a copper leaf with sandstone trim
Keep an eye on your oil level and don't just presume it's the old oil in the water

[kaiser]

There is of course the added possibility, that you might have an additional head gasket failure, that will in some cases give similar symptoms, and could explain failing hoses.
I have a V6 that now displays water loss, a bit of mayo under the oil filler cap and, it seems, slight residual pressure in the cooling system.
So far I have found a tiny leak on the radiator. Next I am going to bypass the oil cooler.
I hope the head gaskets are OK.