Compression test results.

My car has been losing water, and has a lot of steam in the exhaust, so I suspect it has a leaking head gasket. Today, I did a compression test,to see if the fault was evident between

1 or 2 cylinders, or maybe one was out. Anyway, the results were : 250, 220, 150. 185

So, clearly all over the place. Being as the gasket is likely to be leaking, can there be any interpretation of the results? Or are they so wild that no sense can be made of them?

I'll be taking the head off this week for a refurb, so hopefully any problems will come to light then. Thanks.

Reply to
A.Lee
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My car has been losing water, and has a lot of steam in the exhaust, so I suspect it has a leaking head gasket. Today, I did a compression test,to see if the fault was evident between

1 or 2 cylinders, or maybe one was out. Anyway, the results were : 250, 220, 150. 185

So, clearly all over the place. Being as the gasket is likely to be leaking, can there be any interpretation of the results? Or are they so wild that no sense can be made of them?

The difference between 1 and 2 is not a lot, the difference between 3 and 4 would suggest the gasket has failed between them. Did you do a wet test? ie squirt a couple of shots from the oil can into the cylinder you're testing, this will show whether the problem is above the gasket level, or below, ie rings. I would expect your case to be a gasket but you never know.

What car is it BTW?

Steve

Reply to
shazzbat

You can usually tell by looking at the tops of the pistons, the ones with water getting in will be clean and show alloy, the normal ones will have brown deposits on top. You might be able to narrow it down by pressurising each cylinder in turn. Overall it is probably quickest and easiest to remove the head and use a Mk1 eyeball. In the past I have most often seen that head gasket leaks are from number three cylinder, but that may just be one of those things or it may be that three gets the hottest. It would match with your readings though :)

Reply to
Mrcheerful

The head is off now, and surprisingly, the one with the 150 reading was the only one that was dirty (carbon) the other 3 were quite clean - far cleaner than you'd expect any piston that had done 100K+ miles.

There was no obvious damage to the gasket, and doing the steel rule check on the face, the head looks pretty flat too, so it is still a bit of a mystery. It'll be at the Engineers tomorrow to get looked over, repaired etc.

Reply to
A.Lee

No, I only did a quick test on all pots, as I wanted to discount a leaking inlet manifold (they are known to fail, and suck water into the inlet, giving the same symptons as a head gasket failure) Seeing the results all over the place, I knew it would have to come off anyway, so didnt go any further.

Freelander 1.8 petrol. Yes, it had the uprated head gasket 40k miles ago (3 years ago). See my other reply, it looks like there was water ingress to 3 cylinders, which may point to an inlet leak, maybe causing an overheat, then a head gasket failure, but there wasnt any obvious head gasket damage.

Reply to
A.Lee

Ooof.

Who changed it? Somebody with K-series clue, or somebody generalist?

Reply to
Adrian

Make sure they do a valve guide test, they use a special tool that pulls suction against the inlet or exhaust port, it can show up cracks around the valve guide, which is a common trick on those (so I am told)

Most likely though it needs a skim and rebuilding carefully with all the right gaskets, bolts etc.

One of my customers sent his for scrap recently, only one real fault: propshaft centre diff. had gone solid. The engine was really good. He subsequently bought a Discovery and loved it, whilst he had actively disliked the Gaylander (as he called it)

Reply to
Mrcheerful

DIY. Did it when I bought it, along with the coolant piping mods. Has ran fine since then, but just in the last week has been steaming a little too much out of the exhaust. Firstly traced to an inlet gasket,which, is probably the cause of the head failure, as the coolant went low once, though not too much IMV. The temp gauge suddenly went up, but not into the red, then soon dropped down again, so that probably stressed the gasket a little too much - there is a very small gap between the liners, so I'd think any overheating could cause this fault.

Reply to
A.Lee

Was the engine hot when you did the test? Using full throttle?

Reply to
Dave Plowman (News)

Just got back from the Engineers. Warped head - "quite a long way out" was the quote, lifting up at the centre was the fault, probably due to over-heating. £275 for a skim, cut the valve seats, lap the valves in etc. I dont think that sounds too bad.

Reply to
A.Lee

I wish you luck. My niece had similar with her MG, and the repair didn't work - despite it being done by the local specialist for that engine. She scrapped the car. Bought a mint Austin 1300 - 45 years old. ;-)

Reply to
Dave Plowman (News)

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