Diagnosing a failed head gasket
Posted: Tue Jul 12, 2022 12:57 pm
Hi All,
I bought a car recently that had it's head gasket replaced not long before i bought it, it's done 1700 miles since then and i think it has failed again. The garage that did the work has agreed to repair it under warranty if it is the head gasket, my problem is they aren't local and i will need to get it transported to them. They say they will do a dye test to be sure it is a head gasket fault before stripping it down. So i could be risking £150 if i have it transported and it's not the head gasket.
The symptoms are
Yesterday on cold start there were plumes of white smoke from the exhaust and rough tick over so we turned it off and left it.
Last night on cold start almost no smoke, some might say it was just condensation from a cold exhaust.
I checked the plugs, 3 are perfect. No.4 has slight dirt build up on the earth electrode and it is browner than the others. (see picture)
In the bores pistons 1 to 3 have a slight carbon build up, no.4 is clean (see pictures)
To me both of the above are indicators of water in the cylinder, the plumes of white smoke were also obvious but now it doesn't do it even when hot.
I haven't done enough miles to say if it is using water and the oil is still perfectly clean. It's 20 years old but only done 7,700 miles - that's not a typo.
So is that enough evidence that it's a head gasket? I could do a compression test but don't have anything to do a dye test. Any input is appreciated.
Thanks.
Kevin.
I bought a car recently that had it's head gasket replaced not long before i bought it, it's done 1700 miles since then and i think it has failed again. The garage that did the work has agreed to repair it under warranty if it is the head gasket, my problem is they aren't local and i will need to get it transported to them. They say they will do a dye test to be sure it is a head gasket fault before stripping it down. So i could be risking £150 if i have it transported and it's not the head gasket.
The symptoms are
Yesterday on cold start there were plumes of white smoke from the exhaust and rough tick over so we turned it off and left it.
Last night on cold start almost no smoke, some might say it was just condensation from a cold exhaust.
I checked the plugs, 3 are perfect. No.4 has slight dirt build up on the earth electrode and it is browner than the others. (see picture)
In the bores pistons 1 to 3 have a slight carbon build up, no.4 is clean (see pictures)
To me both of the above are indicators of water in the cylinder, the plumes of white smoke were also obvious but now it doesn't do it even when hot.
I haven't done enough miles to say if it is using water and the oil is still perfectly clean. It's 20 years old but only done 7,700 miles - that's not a typo.
So is that enough evidence that it's a head gasket? I could do a compression test but don't have anything to do a dye test. Any input is appreciated.
Thanks.
Kevin.