4age Very Low comp on cyl 3 and 4

[hachirusto]

Hi Guys

Just had this happen to me today completely out of the blue on the way to work, Prior to this my car has been running fine for the last couple of weeks besides a dodgy fuel filter which was limiting the revs.

essential both cylinder 3 and 4 are not running, the car is on running on only 2 cylinders as when I disconnect the spark from either cyl 3 or 4 or both at the same time it doesn't change the running of the engine. Where as if cyl 1 or 2 is disconnected it stalls out.

So I have done a compression test and it has pulled cyl 1= 160 psi cyl 2 = 150 psi cyl 3 = 50 psi cyl 4 = 50 psi

also did a wet compression test and cyl 3 = 70 psi , cyl 4 = 60 psi according to the comp tester it could be the valves.

I also removed the cam covers to just double check that cam hadn't snapped or logged and rotated it by hand and its moving.

so just want to ask some opinions on what it might be , guessing its the valves but don't understand how both cylinders could let go at the exact same time, and car was been driven normally at the time it let go.

any advice would be appreciated also if any VIC guys could recommend a good mechanic that has 4age experience that would be good.

thanks

[Nikkojoe]

16V or 20v?

Id say the head gasket is blown between 3 and 4.

[hachirusto]

16v and oil is clean as underneath the oil cap and the radiator

[jakel]

I would also say possible head gasket, at work one of the guys was checking and blew compressed air through plug hole on no. 2 and the air came out no. 3 one way of checking head gasket.

[Nikkojoe]

16v and oil is clean as underneath the oil cap and the radiator

doesn't always have to take out oil or water!

[hachirusto]

Ok cool guys will double check the head gasket, guess go a compressor and blow some through, I guess if I blow the air through cyl 3 and see if it comes out cyl 4

[jakel]

give it a go, can't hurt.

[slide86]

its the head gasket.

my CA bluebird did the exact same thing. no comp on 2 and 3. it had split the gasket between the two cylinders.

get the head checked for straightness before refitting it.......

[70XIN]

yep, definitely some headgasket love