[Saif2018]

Hi guys,

Recently been loosing about 1 litre of coolant a month. I can't see any leaks, the Water Pump has been replaced with a OEM one, including new radiator and hoses about a year ago.

When I unscrewed the coolant expansion tank cap, i found the last thread had a chip/crack and the o ring was loose. Could this cause coolant loss, from engine heat etc?

The windscreen washer fluid has been evaporating over a period of time as well, due to to cracks on the white plastic filler pipe, but that shouldn't be related.

[mj6234]

I think that is possible. Since the system is pressurized the crack may only leak after the car is running. If you have the original expansion tank, it is very possible it is leaking at the seam. Mine was and had to be replaced 6mo ago. Looks for signs of leaks around the expansion tank is where I would start as this is a very common issue.

[Saif2018]

Originally Posted by mj6234

I think that is possible. Since the system is pressurized the crack may only leak after the car is running. If you have the original expansion tank, it is very possible it is leaking at the seam. Mine was and had to be replaced 6mo ago. Looks for signs of leaks around the expansion tank is where I would start as this is a very common issue.

Thanks, will have it checked out, yeah I think it's the original expansion tank.

[mj6234]

Easiest way is to start the car, let it run for a min, then while it is running, look around the tank seams. That is the only place where I had a leak and it was slow

[Saif2018]

Originally Posted by mj6234

Easiest way is to start the car, let it run for a min, then while it is running, look around the tank seams. That is the only place where I had a leak and it was slow

Thanks, will do.

[Saif2018]

Originally Posted by mj6234

I think that is possible. Since the system is pressurized the crack may only leak after the car is running. If you have the original expansion tank, it is very possible it is leaking at the seam. Mine was and had to be replaced 6mo ago. Looks for signs of leaks around the expansion tank is where I would start as this is a very common issue.

Had another look, couldn't see any leak from the expansion tank, although I found the plastic o ring on the expansion tank cap had snapped. Ordered a new cap with o rings, if that doesn't fix it, guess I'll have to get a pressure test done.

[tcphoto]

Look for a dry white residue in the area of the ET, hoses and radiator. The coolant is blue but dries to a fine white powder.

[Saif2018]

Originally Posted by tcphoto

Look for a dry white residue in the area of the ET, hoses and radiator. The coolant is blue but dries to a fine white powder.

Thanks, but I can't see any residue at all, could be a very slow leak, as it takes about a month before coolant starts going down significantly.

I'm hoping it's because of the O ring on the cap.