My car wouldn't start last week, and after diagnosis from a recommended Audi expert (who I've never used before personally), it apparently has no compression on all cylinders.

Rather than just let him go ahead and take off the head, which is what he's suggesting, I'd rather do a little more investigation, and maybe get a second opinion.

Vag com tells me coolant temp sensor has intermittent fault - so will replace this tonight - I've heard this can result in non starting due to too much petrol.

I'll check compression myself tonight too.

I've read somewhere wrong oil viscosity can cause problems with valves, so I did an oil change last night just in case.

Seems strange to me with no previous problems. And what could happen while the car is parked up for one day ? timing belt is intact, and I think, he said valve timing is ok.

Don't know why he hasn't suggested a cylinder leakage test before taking the head off.

Any help very much appreciated - and many thanks to members for past threads I've been trawling through.