Losing coolant, reassure me!

[DCmk3]

Oh and pipe clamps, are you using original ones or replacement ones? the original ones tend to leak and not hold pressure too well after years.

[Callum_K]

Pipes and clamps are original but show no signs of any leak. Will take a look at the thermostat housing when it's not raining outside. It's strange because it will lose a whole expansion tanks worth in a couple of hours running but then be fine :s Coolant  temp stable at 90, oil temp fine. Have ordered a new expansion cap incase its not venting correctly and over pressurising?

[DCmk3]

Have the engine running, preferably when the engine is cold and it's dry outside, squeeze any of the main water pipes and check for leaks, the reason I say when the engine is cold is so that the thermostat stays closed and will allow a little more pressure buildup around that area, also making it easier to see if there is a leak from that area. And not to mention, you won't fancy squeezing a hot water pipe.

[Callum_K]

Quick easy question for someone! Does the expansion cap on your Mk3 have some kind of seal/oring? Mine doesn't, but neither did the new one I got from VW....asked them and they weren't sure :s

Car is still driving fine with no coolant in expansion tank and apparently not losing any more!?

Anyway have ordered a new tank, thermostat housing, and a selection of jubilee clips to replace all standard clamps.

[DCmk3]

Well mine has no seal on it.

[spudboy6]

just had a quick read of your thread and i might have missed it but i can't believe the thermostat housing hasn't been mentioned !

yes we all know that the black unit on the front of the engine where your leak is coming doesnt actualy house the termostat but thats what VW call it ! , anyways it gets brittle over time and where the two 10mm nuts are the housing cracks due to heat and stress causing your leak .

so change the thermostat housing . and you will need the blank aswell as the new ones have two sensor holes so one part fits all models . cost saving . will come with a new seal aswell and have your self pleanty of coolant to top up and bleed system .

sorry if that has been mentioned / you have solved the leak !


just read it all again and seen someone had said the above but as ive typed it now it can stay 

[Callum_K]

I have replaced that part, it was the first thing I did, however that just exposed a weakness in other parts of the system. Replaced the flange on the side of the head too, and still have a leak. I have a new expansion tank and cap to fit tomorrow so we will see how that fairs.

[Callum_K]

Wahey located another leak! Seems to be from the left hand side of the engine, beneath  the alternator, so guessing waterpump or possibly thermostat housing? Didn't get a proper look and won't do til the weekend. Need to get this sorted though as it's costing me a fortune in antifreeze!

[DCmk3]

Probably leaking between the waterpump and block.

[Callum_K]

Probably leaking between the waterpump and block.

I'm hoping its just the thermostat housing but I will take a closer look tomorrow!