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zak

VR6 Coolant pressurising and mixing with oil

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My car has been stood for some time and now has a couple of problems i need advice on.

 

The car starts okay but is a bit lumpy, i've put this down to it needing a bit of a run to clear it out. My main problem is the coolant has pressurised and mixed in with the oil. The oil looks like the following video

 

Before looking at the oil the heater matrix has given way (which was also changed by myself a few years ago) and the coolant came out the expansion tank too. Before i took the car off the road i had changed the headgasket and it was running fine. The symptoms look much like a head gasket failure but could it be anything else?

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Head gasket does seem likely. Have you had a compression check done?

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Oil cooler I reckon. No reason for the head gasket to fail, knowing the care you take to do a job, unless there was a fault with the gasket itself.

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When my head gasket went it was lumpy at first due to water in a cylinder, garage advised me a compression test might not always show a head gasket failure.

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I don't mind getting the head off but thought i'd look at other options first. I had an oil cooler failure on my previous 330d but the oil entered the cooling system rather than the other way round. I assume this is because oil pressure is a higher than coolant pressure. If this is the case with the vr6 then its unlikely to be the oil cooler. But regardless its worth a look.

 

Are there any other likely suspects? ...I can't think of anything

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I hadn't though about doing a compression test, I'll do one in the next few days as that would help me conclude the issue.

 

If it does come to doing the headgasket, what's the best options for the gasket and bolts? If ECP is suitable that would be great as i can pick them up locally

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Testing the cooler

 

oil_cooler1.jpg

 

Remove the cooler, block one of the coolant ports and fit air attachment to the other port (the pic shows both fitted with bicycle tyre valves), dunk the cooler into a bucket of water and use a tyre inflator to check for leaks.

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Is the VR6 oil cooler functionally the same? It looks quite a lot different to the one pictured (which I'm sure is what's used on the 4 cylinder Corrado's)

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Ah sorry my mistake. I was getting confused with the oil filter housing, not realising the cooler is separate. As usual, ignore me :)

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A bad cooler is not likely to pressurise the coolant system. Oil in the coolant can be the cooler but oil seeping into the coolant won't pressurise the coolant.

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Testing the cooler

 

oil_cooler1.jpg

 

Remove the cooler, block one of the coolant ports and fit air attachment to the other port (the pic shows both fitted with bicycle tyre valves), dunk the cooler into a bucket of water and use a tyre inflator to check for leaks.

 

Love that!

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The pic and method is stolen from another place, the idea is not mine and I take no credit for it.

 

I think its more likely HG failure, but that is a method to diy test the heat exchanger (its proper name) and discount it from any ongoing issue

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Hi Just a quick update, i did a compression test dry with the engine cold and got the following results. I dont who whats considered normal when col but why is cylinder 4 so high? I can understand when a reading can be lower due to worn rings/bores

 

1 180 psi

2 170 psi

3 170 psi

4 235 psi

5 170 psi

6 170 psi

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Hi Just a quick update, i did a compression test dry with the engine cold and got the following results. I dont who whats considered normal when col but why is cylinder 4 so high? I can understand when a reading can be lower due to worn rings/bores

 

1 180 psi

2 170 psi

3 170 psi

4 235 psi

5 170 psi

6 170 psi

 

You can't really do a compression test accurately with the engine cold...

 

Did you also have the injectors unplugged and throttle held open as per the manual?

 

It's very unlikely for a VR to pop a headgasket so I'd look at the oil cooler in the first instance!

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actually i redid it with the throttle open which i forgot to do first time around and now i get. I pulled the fuel pump relay

 

1 180 psi

2 165 psi

3 170 psi

4 175 psi

5 170 psi

6 170 psi

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had oil cooler failure on my old audi 1.8t and tested the cooler exactly the same way, it was only a pin hole so small that coolant couldnt pass into the engine but oil under pressure could only go one way and thats into the cooling system ,the symptoms were {wait for it !! lol} coolant tank full of oil!

 

your need some of this stuff either way http://www.ebay.co.uk/itm/forte-cooling-system-bio-degreaser-treatment-new-/171746562186?pt=LH_DefaultDomain_3&hash=item27fce4908a

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I have removed the upper and lower inlet manifolds to get access. I removed the spark plugs, then turned the engine over by hand a few times. When i did this water spurted out of the plug hole for cylinder 4. Any Ideas on what this indicates?

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I have removed the upper and lower inlet manifolds to get access. I removed the spark plugs, then turned the engine over by hand a few times. When i did this water spurted out of the plug hole for cylinder 4. Any Ideas on what this indicates?

 

HG is breached into that cylinder.

 

I was trying to compression test on of mine and got a shower

 

016_zpsc80825aa.jpg

 

Tripped all the power off to the house lol

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The only other thing it could be is a cracked head or block assuming coolant has not run in via the plug hole?

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It's definitely not gone through the plug hole, I'm removing the head to investigate

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I removed the head and couldn't find any signs of head gasket failure, the gasket looked intact. Overall the head was full of oily Mayo. Cylinder 4 was full of water.

 

I feel like I could waste time investigating without resolving the problem. I'm not sure that a head gasket will fix it. I don't think it's the oil cooler as if it was then there would be oil in the coolant system rather than the other way round. I've had an oil cooler fail in a 330d so have experienced this first hand. Oil pressure is higher than water pressure so oil ends up in the coolant system when an oil cooler fails

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