engine oil in coolant tank

In the US market for the automotive 1.9 TDi, it was said that one should only fit water pumps with metal impellers. The plastic impellers can slip on the shaft. They appear to be ok, but under load they break free of the shaft and fail to pump adequately. It is not an obvious failure. Because the timing belt has to be removed to perform a pump change, it is cheaper to fit a new quality pump than to risk it, or so the logic goes. Access in a boat might actually be easier than in a car.

edit: This applies to what I think are the VE pump equipped engines. One engine code is ALH. If you have a HEUI/PD injection system, then this comment may or may not apply.

 

The small "i", often overlooked, makes a large difference. TD engines deliver a modest 60-70 hp, TDi engines produce twice that and even more, so thermal loads also double.

VW has the nasty habit of using parts that look identical but are not interchangeable. Only an experienced mechanic or someone with access to the VAG library can avoid making mistakes. The 1.9TD had only plastic impellers regardless of engine code, but the number of fins increased from 6 to 8 to improve flow at low rpm.

 

Engine dissected

This took longer than expected, but today the cylinder head was ready for inspection. Quite a disappointment, I assumed to find clear evidence of damage, but the only visible anomaly is a slight discoloration around a coolant hole.
In the pictures head and gasket have only been washed with gasoline.
Frankly I don't exactly know what to look for .

 

I think I see a crack.

 

Im not familiar with these engines, but alot of modern turbocharged engines have a water cooled turbo charger which is primarily for convective cooling of the turbo once the engine has stopped - negates the need for idle down times or turbo timers. There is also oil lines feeding the turbo aswell, could there be a seal inside the turbo that is gone and pumping oil directly to your coolant tank?

 

Second from left between the injector and valve.

 

I see... also what about top right corner, between the 2 galleries?

 

Have the head pressure checked or at least cleaned and magnafluxed.

 

There's an identical line in the third from left.

 

You are both correct!
There are cracks between the swirl chambers of cyl. #2 and 3. I was concentrating on cracks between oil and coolant passages, so I overlooked these two.

Hard to judge if these cracks can cause the fluids to be mixed, but they definitely do not belong there. I'll remove the swirl chamber inserts to see how deep these cracks extend.

 

if there is a break between the water jacket and anywhere else, be it from a crack or head gasket failure, the cooling system will fail to develop pressure and allow the coolant to boil and than the engine to over heat since it is not taking heat away. the boiled coolant is a vapor that does not carry heat away nearly as good as liquid coolant or water. So if the cooling system does not pressurize it will run hot or overheat.

You will not always be able to tell if the head gasket is leaking, even with a compression test. Best way is to test coolant for presence of combustion products (most well equipped auto repair shops have equipment to do this). In your case however, it was clear you were getting oil in the coolant, so there is a breach between a pressurized oil galley and the water jacket, could be a gasket or a crack. Not likely the water pump would cause that to happen.

So it had to come apart either way, if you find no obvious breech between any galley way with pressurized oil to a water jacket in the head you might also consider testing the block for cracks as well.

Good luck

 

I read of putting air pressure into a cylinder by using a modified spark plug that would accept an air hose. If you heard air in the carburetor it was a leaky intake valve, at the exhaust pipe it was an exhaust valve. If you heard air at the crankcase breather tube it was bad rings and if the water in the radiator bubbled it was a head gasket.

I think a rubber end on the air hose, like on a compression tester, would work for gas or diesel, as long as there was someone to hold it in place while someone else checked for noises.

I never tried it, maybe it wouldn't work very well anyways. I think it was back when another remedy, for radiator leaks, was to crack a few eggs and sprinkle some pepper into the radiator with the engine hot and running.

 

A short Google search reassured me I'm not alone. ALL VW engines of this type (and several others as well) suffer from cracks in the head after high mileage. It is regarded as acceptable as long as the path of the cracks is between the valves.
If there are cracks between a valve and the swirl chamber, the cylinder head is declared dead. Mine has two such cracks!

Because of this VW peculiarity, the cylinder heads are not reconditioned, but recycled. The good thing however is that you can buy a (bare) new one for less than $300, a new head with valves and a gasket set for $450 or a complete head with camshaft, seals, gaskets and stretch bolts for approx. $600. I'm told these parts all come from Brasil, where VW has a large factory and lots of supporting industry.

So I ordered a complete cylinder head, ex warehouse somewhere in Germany. Saves me a lot of time; no need to clean the head any further, just the mating surface of the block. From the old one only the injectors and glow plugs have to be transplanted, the rest will be used as garden decoration or add weight to the garbage bin.

And now we come to the reason of this type of head failure.
A German company specialized in cylinder head repair for the more costly BMW, Porsche and Mercedes engines explains that incomplete combustion leaves a carbon deposit in the swirl chambers and other surfaces of the head. The carbon glows, increasing the local temperatures by several 100's degrees and causes damages.
An irregular spray pattern, inferior fuel and low engine rpm contribute to this chain of events.
My boat engines were running on heating oil for the last 5 years, at half throttle or less and I never had the injectors checked......

 

Well, the head was bad, but is that the path for the oil in the water?

http://www.vwt4forum.co.uk/showthread.php?t=123012

http://forums.fourtitude.com/showth...ne-Oil-Found-in-Coolant-Bottle-94-Golf-1-9-TD

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