Just did a compression test.

[osullivant]

As per title I just did a test with my new Sealey compression testing kit. ( I say this because I have not calibrated it so cannot vouch for its absolute accuracy...)

Had a bitch of a job getting my deep socket to go on the heater plug so engine was only warm first time around, then battery failed, hot second time, getting cooler when oil added (and then battery died)

results. each cylinder... 1...260warm 295Hot 337HWet. 2. 270warm 300hot 3.270warm 297 hot 340 hot wet. 4 265 cold 297hot. 5 270cold 290 hot 237 hot wet.

Summary hot compression roughly 295.
Adding oil improves things by about 45.....

Conclusion it is a rings issue???

Any thoughts on things to try,

I guess this explains my burning oil by the gallon, is pulling engine apart the only option.....

[poiuytre111]

Readings tend to confirm gummed up rings. You could try leaving something like Redline SI-1 in the chambers to soak them for a few days but taking the pistons out and fitting new rings may well be necessary in the end. You might want to buy a cheap usb camera to inspect the bores before you go to too much trouble, even cheap ones (£5) can be quite small these days (5mm) allowing inspection without taking head off.

Found this suggestion using google:-
remove the plugs and pour ATF into each cylinder. Let it soak for a few days,then crank the engine on the stater to clear out any ATF pooled in the cylinders then install the plugs and let it run until hot. Once hot and running rev it up with the aircleaner off .
When you rev it up ,use a spray bottle of water and spray a mist of water into the carb while you rev it hard. this will clear out crap from the combustion chamber and the ATF will unstick the rings. If it keeps smoking and it gives a good leak down reading,try the ATF or get some carb or brake clean in bulk. Fill each cylinder and let soak.
GM actually make a product to do this on the LS7 engines which were showing signs of piston slap.
If you use ATF it can leak into the oil pan and won't harm the engine ( actually does a lot of good ) but carb clean or brake clean requires you to drain the oil pan and use clean oil before restarting..

[osullivant]

Thanks for that post, but it raises another question, is there a way to tell that the rings are worn or just stuck, and if stuck how to tell that they have become fully unstuck...

I am thinking seriously about leaving a mixture of brake fluid and acetone in the cylinders for a week..... what harm can it do?

[poiuytre111]

Only way to check rings involves taking out piston, by which time you are not going to want to put old rings back anyway. By all means use whatever solvent on top of the pistons to dissolve gunk around rings but then make sure you get it out and change oil before running engine again as it will pollute the lube oil. Apparently water injection is effective at keeping an engine clean but I'm not sure if it will help once you get to this situation.

[jamie1131]

I stand to be corrected but I don't think you necessarily have a compression problem based on those numbers.
All the cylinders are broadly similar, and I'd expect the wet numbers to be slightly higher. If one cylinder was down and made a big improvement that would be a different story.

[poiuytre111]

Adding oil for a wet measurement can only really change the outcome by improving the ring seal and in, this case, it seems to make a 15% difference. That seemed material to me but I would not claim to be an expert either.

There is certainly something wrong and gummed up rings would have that effect being experienced (oil consumption) and is at least suggested by these figures.

Certainly worth taking the sort of action that might free gummed rings to see if an improvement in compression results can be achieved and then hopefully a return to more frugal oil consumption.

I am all for trying any potential simple fixes before stripping or changing an engine.

[osullivant]

Originally Posted by jamie1131

I stand to be corrected but I don't think you necessarily have a compression problem based on those numbers.
All the cylinders are broadly similar, and I'd expect the wet numbers to be slightly higher. If one cylinder was down and made a big improvement that would be a different story.

It is not just oil consumption it self, also large amounts of blowby. I do not think consistent readings are necessarily not gummed up or worn rings. All have had the same oil. And number of miles covered.

I find it reassuring that there is not one really bad one.

I would really like to hear about other people's test results.

Tony.

[jamie1131]

I'll try and get mine tested this week. How much was your compression testing kit? can't decide whether to buy one or stick the car into a garage and get them to do it.

I have been considering soaking the pistons overnight in plusgas to see if that helps.

[osullivant]

Originally Posted by jamie1131

I'll try and get mine tested this week. How much was your compression testing kit? can't decide whether to buy one or stick the car into a garage and get them to do it.

I have been considering soaking the pistons overnight in plusgas to see if that helps.

I got a bargain on amazon at about £75, the kit seems to retail at about 375 plus in some places, I suspect a less elaborate kit would do, but be aware that sealey suggest the incorrect adaptor for an xc90 glow plugs....

I can check the correct number adaptor tonight.

[davebb]

Hi I would like to know what the part number for the kit and adaptor,
is your care a 163 or 185 D5 , do they use the same adaptor ,
Thanks for your HELP,
Dave