Compression???

[juiceman8]

does anyone know what the normal compression is per cylinder for a 2.7, 4-cylinder engine???

Mine read the following; 1 - 65 lbs, 2 - 80 lbs, 3 - 60 lbs, and 4 - 145 lbs...

Any suggestions on what to do would help, the engine has 183,000 miles on it.

Thanks.

[toyotaman68]

well off the top of my head i would have to say #4 sounds about right but the rest are pretty low for a running vehicle, we have seen a few of these four cylinders with burned valves. try this out, try squirting some motor oil into the cylinders via the spark plug holes, run your compression test again, if the results are the same then it is a valve or head issue. if the pressues go way up then its in your bottom end aka piston rings/cylinder walls. i hope this helps.

[EnolaGaia]

Spec 'good' compression should be 178 psi or higher in all cylinders.

Spec 'minimum' compression should be around 127 psi in all cylinders.

The compression / pressure difference among all the cylinders should be no more than 14 psi.

Three of your four cylinders are below minimum spec, and the difference among cylinders is 'way out of spec.

To help determine what may be wrong, you can pour a small amount of engine oil into the spark plug holes of the 'low' cylinders and re-run the compression check. If adding the oil results in better compression on the 'low' cylinders, this would indicate the rings are shot. If adding the oil makes no difference, it would indicate the problem is elsewhere (probably the valves or head gasket).

[juiceman8]

will adding the oil and doing the compression check again ruin the "compression checker"?!?!?! seems like oil can/would get up inside of it....