RedFox91

The engine on this 91 I just got is wet with fluid (looks like coolant) all over the back of the engine, starting at the rear two plugs (plugs 7 & 8) and going back from there. I've got the car to crank but it won't start. I haven't tracked down why yet but I want to do a compression test. Since it doesn't run, what do I need to do to complete the compression test? I'm pretty sure it will test while cranking but do I need to oil the cylinders or do anything else?

Venomantidote95

Good hot battery and proceed.

AdderMk2

you dont put oil in the cylinders until you find low compression in one of them. The oil is not part of the test, its a way to troubleshoot if the reason the cylinder was low on compression is due to bad rings, or a cracked/hung valve

TrimDrip

The engine doesn't need to start. Just let the piston come up twice on the test.

What I would do is take the plugs out of the engine and blow out the cylinders with air. If a lot of coolant comes out, you got problems. Also after all the coolant is out of the cylinders, the engine may start.

N3mi5is

Rent/borrow a leak-down tester. Compression will only tell you if there is a problem or not, leak-down will tell you where the problem is.

86 5.0L

i do 3 cycles for each cylinder