Oil in water and forces this mix out the overflow

This could be a couple of different things. First, we need to check the actual head gasket using this guide. I would suggest using the chemical test as this is the most definitive way to test it once it is hot.

https://www.2carpros.com/articles/head-gasket-blown-test

https://www.2carpros.com/articles/coolantantifreeze-in-the-engine-oil

We don't have a manual on this vehicle so I am not sure if the filter has a cooler on it but more than likely they do have a cooler which could have cracked and caused the coolant and oil to mix.

Normally this is part of the oil filter but again, we cannot be positive on this engine with no manual.

However, let's start with this info and we can go from there. Thanks

Thanks Kenny,

It’s much the same engine as a Chevrolet Cruze. It does have an oil cooler on the filter housing.
I’m sure the head gasket is ok as all pressures are even, and it runs with no misfires.
How can it get oil into the water in vast amounts, but the radiator also holds pressure? That’s the question.

Okay. More than likely this is still a head gasket that only "opens" when the engine is hot. So, in a short time, it will most likely fully blow out but the way to prove this is to use that chemical shown in the guide above to get the engine hot then test for a blown head gasket.

Basically, there are only a couple places that they can mix and if you are getting large amounts then the head gasket is the likely issue as you can have it hold compression and pressure when cold but mix when hot.

The car is unusable at present. It transfers oil into the water very quickly. I don’t want to run the engine with the vast amount of water in the oil.

I’ve sent for a ‘sniff kit’. I’ll need to renew the oil before warming it up properly.

Oh wow. If it goes that quickly then a head gasket is really the only thing that would make sense.

Are you sure it is engine oil, or could it be transmission fluid? Again, this would be a transmission oil cooler that is most likely in the radiator and the chamber cracks and allows them to mix.

However, if you are sure this is engine oil then we need to exhaust the head gasket as that makes the most sense.

It’s a manual box so no transmission fluid. Besides I’ve had the rad, intercooler A/C evap all off to clean the radiator out.
There will be enough pressure in the oil cooler to pass into the oil system. I’ll wait for the sniffer test.

Sorry. I didn't read that closely enough as you did note it was a manual.

Okay. Good plan. Let us know how it turns out.

Thanks

Hi Kenny, I’m still trying to diagnose this Corsa Turbo.

Update: I haven’t done much anything on this Corsa for a week, busy on a lorry electrics, but I had filled the expansion tank right to the top and after a few days it was empty!
Filled it again and days later empty again! Oily mess is now halfway up dipstick.
I got a ‘sniff test kit’ but don’t want to start the engine with oil/water in the sump.
There are two places where pressure is created.
1. head gasket leak.
2. oil pump.
I think I’m going to strip the head out inc timing case and the oil cooler etc.
Just a pain but it’s a nice wee car so needs fixed.

I totally understand but if I can make one suggestion and that is to drain the oil and put clean oil in it. Then put in a small amount of water only (no coolant) to keep it from completely overheating and you should be able to run it for a quick test.

However, if this is draining and filling the crank case with not even starting the engine then I suspect the head is seriously warped and just allowing the coolant directly into the engine.

So, I would most likely do the same thing and jump to pulling the head.

You can get a straight edge from most parts stores and check for how much warpage there is.

Let us know what you find. Thanks for the update.

I took the turbo and oil cooler off.

Stripping the cooler shows damaged gaskets oil/water so I’ll get new parts, rebuild and do your test you described ie; oil, a little water in it and see how it runs with sniff test.

Sounds great. Thanks for the pictures that is great info. Let us know what you find.

Thanks

Kenny, I tested the oil cooler. The air side seemed to hold pressure okay.
Set cooler up level and filled the oil side with diesel. It all drained out overnight via water inlet. See pics, dark stain on floor is the diesel. So, the cooler leaks but how is the sump getting water ingress?

Wrong picture. Below is the correct one of test.

Maybe I am not understanding the question. If you filled the oil side with fuel and sealed it off so that it held but it still leaked out, then it would have come out the coolant passage, correct?

If that is the case then water is getting into the oil pan due to the oil and coolant mixing. Normally it goes oil into the coolant because the oil pressure is higher but it will go back the other way when the engine is off because the cooling system holds pressure when the engine is off and the oil pressure drops to 0 PSI.

Let me know if I am not understanding but this is general info on these oil and coolant coolers.

I tried to reply but couldn’t see it. This is a test.

Thanks. It is working. More than likely there was something in the text that the site was blocking.

However, it appears to be working now so please let us know what you responded with. Try not to copy and paste anything as that normally is where the issues happen.

Thanks

Thanks Kenny, I’ll go with your idea there. I’ve ordered a new cooler assembly. See if that fixes it.

Sounds great. Keep us posted on how it turns out as I am curious about this one. Thanks for the update.

New filter/cooler fitted, turbo and radiator fitted. Sump plug in with no oil. Fill it with water and pressured it to 15PSI. Dropped a bit overnight but no water came out sump.
Filled sump with oil, spun engine with no plugs in and injectors disconnected to get oil round system.
Started and runs fine. Got it up to 110 degrees then radiator started to heat across and temperature came down a bit.
No loss of water so I think it’s fixed.
Next will be antifreeze and oil/filter change then I’ll put the front etc., back on.

That is great! Thank you so much for updating us and sticking with us to get it repaired. This info will surely help others in the future.

Thanks again.