Pipe Identification

[dipsomaniac]

loss of coolant is rapidly increasing (2 litres, 5 days & 54 miles). no sign of any loss over the last 3 years until today when i noticed this pipe dripping. it looks like it might be the overflow for the cc. can anyone confirm this?

 

i am sure that this is not the problem and I will find out soon what is causing the coolant loss as the part must be about to fail completely.

[Guest 3.5bullet]

that is the drain for the ac condensor, is that signs of coolant under the spout? if it is then your heater matrix is leaking! not good as it's a total dash out job! you would be better to check and bypass the front matrix before it totally fails! you wont want to mop up all the hot coolant from the front foot wells when it goes! and get your ankles treated for burns either!

[dipsomaniac]

thanks 3.5bullet i appreciate your advice. if it is a drain/overflow pipe wouldn't you expect some liquid to come out of it?

 

i have just done 25 miles. it is dripping at the moment but i can't confirm whether it definately is coolant. the heater and air con are working ok - no sweet smells when the heater is on.

 

do you think it is the matrix leaking?

[Guest 3.5bullet]

have you tasted the substance dripping from the pipe? does it feel sticky when it dries on your fingers? if the ac is working fine then there should be some liquid dripping from the drain, try running the engine without the ac on and see if the drain still drips?

[Masked Marauder]

It could be the matrix, but VR6s are famous for the thermostat housing leaking.

[dipsomaniac]

i have thought about the thermostat housing but can't see any evidence of a leak. i didn't want to strip it all down without some indication of it being the problem.

 

i must admit that i am stumped. i have just run the engine with out the cc switched on and no liquid is dripping. i am keeping a record of amount of loss/time & mileage and will also see what happens if i don't switch on the cc. i also need to test the coolant to see if any exhaust gasses present.

 

it must be going somewhere??

[sepulchrave]

Now I know this is gonna sound daft but...

 

My thermostat housing only leaked visibly just before I took it off the road due to staggering levels of coolant loss.

 

I can only guess that this is because the housing is thermoplastic and the cracking which caused the leaks was only opening up under pressure, as soon as the car was stopped the leak would stop.

 

This is why I had to rip the entire face off my car because I didn't know where the leak was coming from, after all diagnosis is 9/10 of any awkward job.

 

I would say in conclusion that your problem is 90% likely to be the thermostat housing since you have a VR6! :rolleyes:

[seatkid]

I think thermostat housing leaks are quite common on a lot of VW engines. It leaked on my golf - corrosion on the aluminium face where the housing sits. You don't see because it only leaks under pressure and when the engine is hot. When it leaks the coolant is hot and evaporates readily. The only visible clue is the white patch left behind......

[dipsomaniac]

i am really looking forward to the day i can solve this mystery. have had climate control switched off most of this week and it appears that i am not losing as much/if any coolant. i have been monitoring the loss:

• 25 june, 0.5 Litres, 230 miles & 3 days since last top-up (cc on)
  
• 4 july, 2.5 litres, 165 miles, 9 days (cc on)
  
• 8 july, 2 litres, 58 miles, 4 days (cc on)
  
• 11 july, 0.3 litre, 59 miles, 3 days (cc switched off at times)
  
• 12 july, no loss, 38 miles, 1 day (cc off)
  

has the cc system got anything to do with the loss or is it just co-incidence? could it still be the thermostat housing?

[sepulchrave]

I'm sorry but I really don't see how the CC can have any relationship to coolant loss, it is a totally independant sealed system containing a small quantity of CFC based refridgerant.

 

There is a condensate drip pipe as you have noticed but this is a red herring.

 

You are losing coolant, and unless there is a head gasket issue and the coolant is being burnt then you have a leak, and it is most likely from the large ugly thermoplastic lego block located beneath your coil pack on the side of the block just above the bellhousing, this also contains the thermostat and it is nigh on impossible to test, you will have to remove it and visually inspect the interior to spot the problem.

 

It is a common fault on VW engines once they have reached a certain age, and yours has! :D

[dipsomaniac]

thanks for all of your advice. it does look like thermostat housing is the favourite. i just didn't want to remove half of the engine without having some evidence of that being the problem.

[dipsomaniac]

Sepulchrave, 3.5bullet - when your thermostat housing leaked did the coolant loss just get worse or did the coolant loss fluctuate either way?

 

can anyone offer any logic as to why i don't appear to have lost any coolant in the last 3 days, 120 miles with the climate control unit switched off. Last week I lost 2L in 4 days, 58 miles with the cc on? Is there no connection?

[Masked Marauder]

The only thing I can think of is the increased load on the engine. It can't be to do with a leak because as far as I am aware the pressure in the matrix is the same with the heating on or off.

[dipsomaniac]

Finally found the problem and had a nice heated foot wash at the same time. Unfortunately, I was 15 miles from home, my insurance only covered 10 miles (gave me a bottle of water and said "on your way, son" - that is another thread?

 

Can anyone give me any advice on removing the dash? A little window in the dash when manufactured would cost nothing and save so much grief when replacing the matrix.

 

Just bee quoted

[dipsomaniac]

if it is a vw part how can they quote 160 + VAT when ford are quoting 80?