88 245 Low Compression Cyls 3 & 4 + Coolant Leak

Post by **rgk** » 13 Apr 2014, 15:14

Engine making a terrible noise under load, I took it to a mechanic for a quick look who immediately diagnosed a misfire. Checked the spark plugs, looked good. Checked for spark, good.

Checked compression: cylinders 1 & 2 about 150 psi. Compression at cylinders 3 & 4 about 40, causing the engine to limp. Testing the compression, I see that in cylinders 3 and 4 it is low on initial and successive strokes.

No coolant in oil, no oil in coolant. Engine has never overheated. This probably just means a bad head gasket, right? In the seven or so years we've owned the car, we've never had to replace it, and I suspect it's never been replaced.

I noticed coolant weeping between head and block beneath cylinder 4 for weeks before the car started limping. Today I notice coolant weeping beneath cylinders 3 and 4. My guess is that cylinder #4 had a misfire for a while, and that the break in the gasket has spread, causing three and four both to misfire, causing the severe condition.

In all likelihood this is a bad head gasket. But could the low compression be caused by anything else that I can check for?

5ft24 · Post by **5ft24** » 17 Apr 2014, 09:05

It sounds like the head gasket is blown between cylinders 3 and 4. Was the engine pinging before all this started? That can cause damage, including burning the head gasket. I would not drive it anymore so as not to cause any further damage. Definitely need to pull the head and have it checked by a machine shop for straightness and for cracks.

Post by **mtd240** » 21 Apr 2014, 17:00

Pick up a full headgasket kit - Volvo part number 270689.

FCP also sells an Elring kit for ~$60.

OE Volvo is ~$100 from Tascaparts.

Post by **rgk** » 27 Apr 2014, 08:24

I pulled my head and discovered that it is, unfortunately, cracked between several cylinders. I have found a replacement head and am working on cleaning it before I put it on. I looked at those FCP kits and am very surprised to see how reasonable they are. Will definitely be purchasing from FCP Euro.

difflock54 · Post by **difflock54** » 27 Apr 2014, 17:33

Worth you having a qualified machine shop check over the replacement head before you fit it.
Could be warped and a skim is well worth the expense. They can reseat the valves etc also so it's then good to just refit.

Post by **rgk** » 28 Apr 2014, 07:43

Yep, for sure. I just dropped it off at the shop. The old lady wouldn't let me not have it checked. God bless her.