Please help VT cooling system issues.

[Will.k]

Hi Guys, can someone/anyone please help me my VT S1 commodore done a radiator last night and ended up costing me a $300 joyride in a tow truck.

The temp gauge didn't come up at all that i saw and the engine cut out with the usual temp of 1/3 displayed.

I fitted a replacement radiator to it today and it is idling rough and running even rougher in gear (auto)

I made sure i had the heater on when refilling.

There isn't any oil in water or vise versa.

Could this still be an air lock or something more severe.

[wortus]

I think you need to give it a compression test and take it from there.

[Will.k]

Hey wortus, is there much involved in giving it a compression test? can i do it myself or will i need to take it to the mechanics?

[TMM]

Hey wortus, is there much involved in giving it a compression test? can i do it myself or will i need to take it to the mechanics?

If you buy a compression gauge you can do it yourself. You remove the spark plug for a cylinder and install the gauge in the spark plug hole, then crank the engine and get the reading from the gauge. Do this for each cylinder and record the compression in psi for each cylinder.

This will tell you if each cylinder is holding compression or not. On a healthy engine all the cylinders should have roughly the same compression (i think about 110-140psi is normal for a V6?). If one or more cylinders have a lack of compression, the most likely cause is a blown head gasket and warped head from overheating. This will require the head to be machined flat, new gaskets and head bolts to be installed.

[Will.k]

No worries, thanks guys i'll give that a go. Can anyone give me a worst case scenario cost if it is a warped head or blown gasket?

Cheers.

[edals]

If thats the case prolly be cheaper just to get a second hand engine fitted, its a really big job to machine heads and replace head gaskets.

[graham7773]

1 PSI = 6.895KPa
According to the VT service manual from GMH, the ecotec VT V6 lowest cylinder compression should be 689KPa and the maximum difference between cylinders must not be more than 138KPa for good running. This would also suggest a normal cylinder compression of 827KPa. if you want it in PSI, divide 827KPa by 6.895 so normal pressure = 119.9PSI roughly and lowest = 99.9PSI

[Will.k]

Thanks guys i had a mate come out today and it's the head gasket, it's pressurising the cooling system. I'm taking it to his workshop tomorrow (thanks to good old RAC) and we're gonna do the compression test and replace the gasket etc. Hopefully should have it on the road again by wednesday and i will have gained a little knowledge along the way. Making the best of a bad situation and learning something from it.