EB Falcon Compression down

parsonsfamily1, Oct 10, 5:11am
I have a eb falcon 6cyl 4.0 ltr multi-point. running rough so did a compression test. 1- 155. 2-149. 3-150. 4-150. 5-151. 6-74. (psi)
got a problem there on 6. where should i start! do these have any common problems as to why that has happened! thanks

kingfisher21, Oct 10, 5:13am
Start with the head gasket.

dent, Oct 11, 6:32am
did you try doing a wet compression test!

parsonsfamily1, Oct 11, 6:39am
what is a wet compression test! and what will that show !

dent, Oct 11, 6:50am
you add oil to that cylinder then redo the compression test. If the compression reading gets better then its proberly rings leaking. If compression is no better then more likely valves or possibly head gasket.

fordcrzy, Oct 11, 7:23am
head gasket.

theres a water gallery that runs very close to #6 and has a very thin section of gasket there.its also in a spot thats a bout half way betewwn the bolts so it isnt the best clamped spot.

Pull the head, give the valve seals a good look at/replace and refit head.

mybaby, Oct 11, 7:28am
If the head gasket was leaking enough to drop the compression from 150+ to 74, the pressure build up in the cooling system would blow the radiator apart very quickly.

franc123, Oct 11, 7:33am
I would get a proper cylinder leakdown test done before doing anything.

steve312, Dec 29, 1:09pm
Compression test, wet and dry, leak down test and TK test will point you in the right direction before aimlessly pulling the head off with no idea where the compression leak is.