QuestionI have recently (6 months ago) rebuilt the engine and all its components have been replaced of renewed as required.
I find that with a 15psi cap on the coolant header tank that there is a slight leakage of coolant every week which is now more pronounced in the hot summer months. (Ambient temperature in Brisbane Australia is 30C to 34C.)
Should I replace the new 15 psi cap with a 16-18psi cap to prevent the loss of coolant which I am now experiencing?.
Appreciate your comments.Thank you Mike Shepherd.
AnswerHi Mike,
My procedure if you had come in to my shop would be.
Does it show any high temp on the gauge?
Loosing some coolant out the cap I would check that the reservoir was not over filled then pressure test the cap. If your car has an over flow tank like the US version, you need to confirm that it is not stopped up.
If that was correct, I would test for CO in the radiator. Either with CO/HC equipment or, if that is not available get some of the dye available from any auto parts store that tests for CO in coolant. This tests for a head gasket leakage.
If that tests OK.
I would check the ignition timing and fuel mixture. Incorrect ignition timing can run combustion chamber too high and a lean condition in fuel mixture will do the same.
A fresh rebuild engine will run a little hotter than an engine with some mileage on it due to the lack of a coat of carbon in the combustion chamber but should not cause over heating.
If all that is correct, you need to remove the thermostat and test it in a open pan of water on a burner for it's opening temperature. Also you may need to have a radiator shop test your radiator and you check to see that your fan is ok. The US models came with a fan clutch which can fail.
Let me know,
Howard
