Mysterious Coolent Leak T5 2006

[sanj]

There is one test you have not performed!

A cooling system pressure test.

I have one as I'm sure Tim does too. We would be able to pressurise your cooling system with the engine off up to about 15psi. Then and only then will you be able to look for coolant leaks, listen for hissing noise of maybe a split hose or leak somewhere and watch the needle on the gauge to see if it drops (indicating a blatant leak).

I did say Cooling system pressure test....not chucking oil down your cylinder bores, which is not the same thing. That is a cylinder Compression check!
Just doing a sniffer test is only half the checks and only tells you that there is no combustion gases present in the cooling system, which there shouldn't be.

it would be great if you could pressure test the cooling system for me, I have been looking into it but the kits are bit pricey, how would we go about arranging that..?

cheers

[LeeT5]

it would be great if you could pressure test the cooling system for me, I have been looking into it but the kits are bit pricey, how would we go about arranging that..?

cheers

Well that depends on your location in the country?

[hillmangt]

Could it possibly be showing a large coolant loss after initial filling due to air locking in the system. You don't say over what sort of mileage or timescale you are losing the coolant or indeed how much. As previously stated a poorly functioning cap or leaking reservoir can lead to loss of coolant simply because it boils off due to not being pressurised. The only way you will find out is by changing parts one by one or get a pressure test done when cold. good luck .

[Baj]

Just gonna add my own experience here.

I had a mystery leak too. It started as top-up (warning lamp) once a month and randomly progressed to a couple of times a week.
I took it to my mate who did a pressure test. It was slowly leaking but neither of us could find where.

He refilled with antifreeze and it stopped for about 3 weeks, then it was suddenly daily top-ups and then every journey.

Eventually we found some water on the top backside of the front lip (in fairness it was raining a lot of the time it was leaking but still we should have seen it with the amount coming out) and there was a tiny (barely perceptible) stone hole in the radiator somewhere.

[LeeT5]

Could it possibly be showing a large coolant loss after initial filling due to air locking in the system. You don't say over what sort of mileage or timescale you are losing the coolant or indeed how much. As previously stated a poorly functioning cap or leaking reservoir can lead to loss of coolant simply because it boils off due to not being pressurised. The only way you will find out is by changing parts one by one or get a pressure test done when cold. good luck .

A Cooling system pressure test kit can test the cap as well as the cooling system.

[sanj]

Well that depends on your location in the country?

sent you private message cheers

[Baj]

If you are down this way I know someone who can help too

[sanj]

if anyone is in the Birmingham area with a cooling system pressure tester I could borrower, id be happy to bribe you with beer

[LeeT5]

if anyone is in the Birmingham area with a cooling system pressure tester I could borrower, id be happy to bribe you with beer

If you don't know what your doing with one and more importantly, what to look for, then I wouldn't advise that.
Best you seek professional advice rather than waste money on a cooling system pressure tester.
They don't come with instructions and you could easily misdiagnose a fault without proper training on one.

I think I live too far away for you to travel, Tim is much closer and probably your best bet. 150 miles with a suspect cooling system issue is generally, not recommended.
If Tim is busy (which is always the case) then a good local garage may be a better option.

Wouldn't want you to cause a bigger problem by driving it a long distance.

[LeeT5]

So, did you find the leak?

[sanj]

I have pressure tested all 5 cylinders and sniffer tested the coolent expension tank and all looks fine. Solid 13bar pressure and no exhaust gases in the coolent.

So, I can only believe that somehow the turbo or coolent lines going to the turbo is leaking coolent directly into the exhuast, can this ever happen??

Thanks

[LeeT5]

I have pressure tested all 5 cylinders and sniffer tested the coolent expension tank and all looks fine. Solid 13bar pressure and no exhaust gases in the coolent.

So, I can only believe that somehow the turbo or coolent lines going to the turbo is leaking coolent directly into the exhuast, can this ever happen??

Thanks

You need to pressure test the system not the cylinders!

[sanj]

Oh yeh, I've not pressure tested the coolent system yet, I forgot you mentioned that before ..

But entertain me a little, could the turbo or coolent lines running to the turbo leak coolent into the exhuast directly?

I pressure tested the cylinders to make good of the head gasket

[LeeT5]

If coolant was leaking directly at the turbo and into the exhaust, the car would be undriveable! You would have plumes of white smoke from the exhaust, so I guess, you can rule that one out.

If you properly pressure tested the cooling system, you'd see the gauge needle on the tester drop with a leak. You'd also expect to see coolant appear on the floor and possibly hear it leaking, all this with the engine off!
If the engine is running and you do the same test and the coolant is leaking via the H/G, then the gauge needle would rise abnormally and not in correlation with pressure from expansion of the said coolant. This could only really be detected by someone with experience of using the tester regularly in the field or by a garage, not by a one off home mechanic.
Remember, you're diagnosing the cause of the symptoms not the symptoms of the cause!

You can check to see if the waterpump is working with a CSPT (Cooling system pressure tester) also with as little as 5 psi on the gauge and a negative or positive movement on the gauge with a blip of the throttle, depending on which side of the WP the gauge is. If you get no movement, often difficult to see, then suspect WP function.

With a CSPT alone you can check/diagnose:

WP function
Static system pressure
Expose HG leaking internal/external
Cap pressure and function
Test above with engine running or off.

It is vital a CSPT is used correctly as misdiagnosis through inexperience is common place and injury by scalding is also possible.

I would seek professional help Sanj, else it may cost you dearly if you get it wrong.

[sanj]

Booked in for the 18th July