Morning all. How long should a healthy cooling system be able to hold pressure when tested with a pressure tester? The car in question is a diesel Focus (not sure what engine or age, as it's not mine)! The chap suspects a head gasket problem. Apparently they have a weakness in a plastic spout around the expansion tank. This failed and he overheated briefly. The expansion tank and associated parts were replaced, but since then, it has developed a slow coolant loss (maybe half a cupful a week). He's wondering if it's head gasket?
Cooling system pressure test - how long?
- Thread starter Avocet
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Should hold pressure indefinitely, that’s the point of a pressure test.
Any sign of bubbling or oil in the expansion bottle.....the usual stuff?
I'd be looking for coolant crusts around the water pump area on these, together with that familiar smell......!
John
I'd be looking for coolant crusts around the water pump area on these, together with that familiar smell......!
John
Nice idea, but no. Even the seals in the pressure tester itself won't hold pressure indefinitely. I'm sure if you pumped one up (just connected to itself) and put it away in its box, the pressure would have dropped away by the time you next come to use it!
Any sign of bubbling or oil in the expansion bottle.....the usual stuff?
I'd be looking for coolant crusts around the water pump area on these, together with that familiar smell......!
John
I don't really know, as I've not seen the car. Trying not to get too deeply involved, if I'm honest! I'll ask him. I think he's had it to various garages over the last few months and they've not been able to find anything.
That would indicate a faulty pressure tester and not the system though.
Obviously not literally indefinitely as you’d need to drive the car at some point! Theoretically though if nothing is leaking, the system and the pressure tester should not lose any pressure if everything is okay. Of course, in time the rubber seals in the tester would age, harden, perish and then leak but that’s just being pedantic....