Porsche Enthusiasts Club Forum

Hi all,

I have some questions regarding water loss with my 944 Turbo. The intention is to collate some information and produce a write up at the end. I've done a lot of research so far, and there are some great videos of rebuilds which allow you to clearly see problem areas in terms of water loss.

In short, I am losing water, around about 1 litre a week at the moment. I've had the car on a ramp and run it hot and checked all the hoses and the radiator itself and there are no leaks. The heater matrix is sound also and it looks as though the water pump is ok, but there is a small oil leak at the bottom of the timing cover so its hard to see at the moment.

What is the best way to start diagnosing my issue without stripping down the engine at this stage. So far i've:
1/ Visual check on water hoses and rad
2/ Run the car hot and checked for leaks (on a ramp)
3/ Pulled out the plugs to check if they're wet (they are perfectly fine)
4/ Checked for moisture on the dip stick (none, some in the filler cap but I do loads of short journeys)


My head gasket was done 5k miles ago about 18 months ago. I think the next step should be to retorque the head. Could someone share the torques for this, and let me know how much I need to strip down to get at these head bolts. Looks like a lot of ancillaries.

The head gasket may not have failed given its new, but the head may need retorquing or it wasn't skimmed (I'm sure it was but you never know).

Thanks all

Two easy ways to check.... get your local MOT station to sniff the header tank (with their gas analyser), and buy one of the sniffer kits that use a fluid that change colour... think they are £20-£30.

David

Surely kick off with a compression test at home. Takes all of 5 minutes.

Compression test results are excellent.
I've recently fixed an exhaust leak which was causing the turbo not to work. Since then I've been noticing this water loss.

Given the amount I've refilled it the coolant is mainly water not, next to no antifreeze in it.

No water in the oil, or oil in the water. I'll run a chemical test soon but given the compression test results and the HG is new I'm wondering is its being lost elsewhere.

Any thoughts?

I think you'd probably notice a litre of water a week going into your engine oil....

Diagnosed update. Any help welcome in diagnosing this as bad HG.

I fitted a tube to the expansion overflow and put this into a catch bottle to see if I was losing water here on the turbo. Bone dry.

Last run out driven hard and I lost 1.5 litres.

Compression test excellent.
Spark plugs all dirty.
No moisture on dipstick
Tested radiator cap all fine
Pressure tested system all fine

The only other fault could be the water pump I presume?

The other indicator I have is that after a hard drive the other day I drove off the next morning to find a large puddle of what looked like coolant on the drive.

Given the amounts I've topped up the coolant over the last to weeks, the system is now nearly all water. I'm about to pull the head off and investigate but welcome any advice before I get there.

I would do a cylinder leakage test to test for head gasket etc.
Water pumps do give failings if the engine is not used for long periods, it seems the seals stick and tear and leak water when the system has cooled down or once when the coolant cap is removed when nearly cold.

Hi
Its bad practice to top up with water as its best to mix some antifreeze and water to use as top up. Failure to use antifreeze will result in internal corrosion leading to alloy silt build up, which in turn lessens the coolants ability to cool.

I am an old toolmaker by trade and in the old days of the 60's some cars having alloy heads for the first time fooled mechanics who had been brought up on only using antifreeze in winter.................I skimmed a lot of alloys heads that were wrecked and eaten away by water.

One other point is that a water leak into the oil does'nt show until the oil pump sucks it in as oil floats on water. If the dip stick shows oil level rising!!!!

The last time I had a mystery water loss the head gasket was allowing just a little to escape but was not blown on cylinders.

Good luck with the search.

So you're losing lots of coolant, have got decent compression test results, no blue/white smoke, no emulsification of oil etc.

Surely got to be a simple leak.

If you're not noticing puddles of the stuff every time when parked then one must assume it's being burned off somewhere in the engine bay.

I'd be looking at the alloy carrier pipe that runs along the top of the exhaust manifold, the water pump and all around the rad.

One other option would be to add a U/V additive, run the engine up to temp and use a black light to check for leaks.

Could you be losing water from the secondary water pump that runs once the engine is switched off ?

Yes, it does seem to point to a leak somewhere in the coolant system as all the test results for a bag HG have come back negative so far.
There is some white smoke out the exhaust on start up occassionally but i think thats condensation since I don't drive it often.

I've pressure tested the system and run it to temperature and inspected while the cars on a ramp. No visible leaks anywhere, and none from the auxillary pump when I turn off. I'll try the radiator leak stuff as you suggest. Really hope its not a bad HG.

Just a thought
Some years ago the wifes Fiat X19 had a mystery water loss and it was leaking from the inlet manifold gasket and being sucked in to the engine.
I later had the same on my track prepped Dolly Sprint and in this cars case the water was leaking into one cylinder and caused a piston failure.

You've had your share of bad luck then. If this was the case I assume one of the spark plugs would be "clean" looking. This isn't the case.
I'm 99.9% certain there is no external leak. I'll have to strip her down next weekend.

Yes the water tends to make things light grey.
I would not say I was unlucky as 35 years track playing is going to throw up a few problems The Sprint managed 10 years no problems so it earnt its right to complain.
Oh the wifes X19 was a Goodwood regular too!

Good luck with the strip down I

Cheers. Any pointers for the rebuild, i've got a load of guides online already but doesn't hurt to ask.

I'm replacing all the gaskets and i'll go for a wildfire headgasket since its the uprated one.
I'll replace the pesky heatsheild under the exhaust manifold because mines cracked and rattling like many turbo's do.
I've got a hose kit to do the turbo lines under the inlet manifold too.