Vauxhall Corsa lost all compression

Hi, you need to check that your timing is ok. If your timing chain has slipped a tooth ( not sure if your car is valve safe, if it's not and it has slipped a tooth you would know about it). If your timing is out, the valves will still be open on the compression stroke which means your have no or very little compression.

The other cause of no compression among many is piston ring failure, to check this do the following.

Remove all spark plugs
Using a compression gauge, pressure gauge "0- 200 psi" connected to a tapered rubber bung will do the job, press this over the spark plug hole and get someone to turn the engine over. Take a reading on the gauge.
Do this for all cylinders and note the readings. If you have no compression and your timing is ok it’s most likely to be the piston rings.
If you have some pressure and find it a bit tricky to hold the bung over the plug hole, Poor a small amount of clean engine oil into the spark plug hole and repeat the above steps to obtain a new set of readings.

If you get a big increase in pressure, this will indicate worn rings and they will need replacing. (The oil will momentarily make a seal around the piston.)

One other test, if you can get the engine started, remove the engine oil cap while the engine is running, stretch a clean plastic back over the hole (make sure you hold into this and don’t let it go into the engine) and see what happens to the bag. Try this at different engine revs. If it gets sucked in to the engine a little or just sits there this is fine. If however it has a tendency to inflate the plastic like a balloon, this indicates burnt gases are escaping down the side of your pistons (this should not happen) and pressurising you crank case. New rings needed.

Hope this helps and good luck !

hi facelift
excellent advice from ramrod69.one thing puzzles me, are you sure timing is chain driven, as the year of your car would normally indicate belt driven timing. please don't get me wrong on this matter as i've assumed your car is not that old & most new breeds of cars these days have changed to the belt driven type to eliminate noise mainly. regards dj dave