Unexplained coolant loss

[martyw]

Hi, just to keep you up to date with progress. This morning I drained all the coolant from the system and found it completely clean. Next I drained the oil and was surprised to see that there was no emulsification in fact it was as clear has when I replaced it, so that would suggest that the coolant is escaping somewhere else, god knows what I was seeing last night.
I removed battery, air box and as many hoses as I could and checked the turbo shaft, there was a little oil visible on the air inlet side but not excessive. The air outlet was clean and so was the hose however on checking the turbo shaft I found what seems like about 3mm of play on the shaft. I now intend to remove the turbo and check internally for crystallization of the coolant because the cartridge will need to be changed anyway because of the play in the bearing.
More later Regards Marty

[martyw]

Originally Posted by kaiser

If there is water loss internally, there are a few ways that can happen.

Headgasket.
Inlet manifold gasket.
Crack in head, block or liner
Liner seal at the bottom compromised.

The engine light indicates it finds its way into a cylinder, and you have misfire,

I think we can thus safely ignore faults in the cooling systems and outside leaks as the main cause.

I would pressurize the cooling system to gain more information.

I would also just like to stress, that the standard torquing of the head gasket will give too low values, and that water loss can easily come from that.

And, worry about all the other add-ons discussed only when you have found
the root cause of your problems.

I include a link.
http://www.the75andztclub.co.uk/foru...d.php?t=214880

of special interest note the torque procedure discussed in post #34.

Hi, I actually used you article for tightening the head bolts, I found it when searching the forum for information on changing the head gasket on this particular model. I found that each bolt required re torquing three times before I was satisfied that they where all at the same. So I thank you for that information.
Regards Marty

[kaiser]

Originally Posted by martyw

Hi, I actually used you article for tightening the head bolts, I found it when searching the forum for information on changing the head gasket on this particular model. I found that each bolt required re torquing three times before I was satisfied that they where all at the same. So I thank you for that information.
Regards Marty

My, my. Somebody actually listens!!
Nice to know.

BTW, if you want to see if you are loosing water inside the engine, check the oil filler cap! If the engine is hot, and you still have water and or emulsified oil inside the cap, water is getting in there, somehow.

If you have not filled the coolant system properly, it is possible that there could have been trapped air behind the thermostat. That would show as a loss of coolant, once the engine gets hot and the thermostat opens. However, once filled, that should not re-occur.

If that is the case, then the misfire could be lack of fuel (filter housing? becoming separated, regular occurrence) OR a problem with spark.
If, you have water in the one cylinder, it should also be possible to see on the plug itself, it should have a different colour to the remaining plugs.

This is a conundrum, an enigma inside a riddle!
But we will get to the bottom of it!

[martyw]

Finished removing the turbo and is totally knackered, wiggle one side and the other side moves in the opposite direction, about 3mm movement. I am going to order a replacement cartridge tomorrow. I am still left puzzled to were the coolant is disappearing to, I am 99% positive it`s not going in to the sump because the oil is clean and clear. So that leaves one alternative as far as I can see and that`s through the turbo and down the exhaust. I think that would also fool the lamba and cause a fault similar to what I received.
Regards Marty

[T-Cut]

Originally Posted by martyw

Finished removing the turbo and is totally knackered, wiggle one side and the other side moves in the opposite direction, about 3mm movement.

QED. The turbo was indeed damaged when the head gasket failed. HGF in the 1.8T can be a rather expensive problem for the unwitting driver.

It's unlikely you'll see any 'crystallised' antifreeze in there. It will appear very sooty, oily and wet. Replace the turbo or just the CHRA and I reckon you'll be fine.

I am going to order a replacement cartridge tomorrow.

Can recommend the UK manufactured Melett cartridge for about £170 (ebay) . It comes with a balance certificate and 12 months' warranty. But you must replace the oil feed pipe for this to apply.

I am still left puzzled to were the coolant is disappearing to, I am 99% positive its not going into the sump because the oil is clean and clear. So that leaves one alternative as far as I can see and that's through the turbo and down the exhaust. I think that would also fool the lamba and cause a fault similar to what I received.

Correct on each point I'd say. The slop in the shaft is an unrestricted exit for coolant and oil.
Lambdas don't like contact with with engine oil. Components in the oil can cause contamination of the 'element'. If the lambda continues to be a problem, it should be replaced.

TC

[martyw]

Hi,
thanks for your replies and advice. I am considering, while the engine is stripped down, double checking the head gasket and changing it from the single layer to the MLS type as fitted when I purchased the vehicle, but a better quality one. I would hate to get it all back together and have the same problem happen again. Besides that I have to go in to hospital next Wednesday for an operation on my ribs so it will be sometime before I will be able to get back to working on the car.
I will let you know how the repairs go and the outcome.
Regards Marty

[minimutly]

How exactly does coolant get through the jacket/seals in a turbo?

[T-Cut]

Originally Posted by minimutly

How exactly does coolant get through the jacket/seals in a turbo?

It can't. I really don't know why I said it could.

TC

[T-Cut]

So there are shaft seals on the coolant side as well? I thought a worn shaft/bush bearing might allow coolant to bleed into the exhaust system, but had second thoughts after looking at the central casting. Isn't the coolant jacket isolated from everything? Just a cavity cast around the bearing housing? Having said that, the turbo I repaired was definitely wet as well as oily. Of course turbos are ruined when coolant gets into the engine oil via a failure in the head gasket. So that may well be the origin of the water seen in a failed turbo. ??

TC

[T-Cut]

Originally Posted by MGJohn

3mm play is HUGE. It will surely allow oil and/or coolant to pass into the inlet or exhaust systems. Both coolant and oil will be at high pressure in a running engine..

Yes the oil feed to the turbo bearing is at full running pressure, but how so the coolant? How does the coolant get inside the compressor housing? As I saw it, there's no route for the coolant to take.

TC