Hi,

I just bought my first car recently with 128,00kms on the clock for AUD$2000 (market val = 6000)
My car leaks coolant out of the expansion tank when hot.

It sometimes has difficulty starting and occasionaly has a very slight miss when warm.
I have a new thermostat, new water pump, new hoses and resevoir cap......I think my radiator is ok.

I had the engine compression tested and the coolant system pressure tested and en emission test on the exhaust system. Everything seemed ok when the mechanic tested it idling in his workshop.
He couldn't bring about the leak.

My problem seems to develop when the car is running. One day the car began to miss slightly and the temperature rapidly rose to red line and white (poss coolant) smoke came bellowing out of the exhaust.

I pulled over let the car cool and topped up coolandt and drove it back home (it worked smoothly, no white smoke)

I have also noticed mildly poor fuel economy and i think this car should have slightly more power for this engine.

The questions are:
Do I have a cracked head ?
Could it be just a bad gasket ?
Is this plausible explanation to the expansion
cap leak ?
The poor fuel economy ?
Could it be something else to do with the cooling system and not the engine ?
How do they re-condition the heads and will it last ?
What causes the crack ?

The engines in these cars are all alloy (i think ?...corrosion?). My mechanic (seems honest) suggests fully re-conditioning the head to new.... he wants $1100-1500maxAUD.

The car is otherwise in very good condition.

Regards
David.