head gasket repair

[omojamie]

would this test possibly rule out rings?
Or is it most probably rings? If so, how do the 'Resstore' type products work?

Thanks again.

[omojamie]

So, here's my last question for you all. Thanks again for your input.

The Mechanic says that he doesn't need to do the leak down test, since the compression builds w rpm, it has to be a bad ring.

Was there any way to know this before we started the job?
Is there any sort of mis-step in the job that could have caused this?
Or do I just have bad luck?

Thanks again.

[JDS60R]

Whoever took off the head should have tested the valves. It would have been obvious that the rings were suspect if the valves had been properly checked.

The test needed was a leak down IMO. The rpm increase also decreases the open times of the valves does not clearly differentiate between rings and valves.

Both could be leaking and you can not find out which without a leakdown. The normal test if you think its a ring only is a wet test where oil is placed into the cylinder to help seal the ring and a noted increase in compression at starter speeds can be seen.

If he replaces the ring and it doesn't get normal compression will he do the valve for free?
Or did he check the valves (if so share how) while the head was off the car.

[omojamie]

So, after the Head Gasket failure it was possible to check if the rings were OK?

This is vital , as we may have just decided to scrap the car (or get a new engine) if it needed a complete re-build.

Now that the engine is re-assembled and running poorly what can I do?
There's no way I'll convince him to tear it down and replace the rings.

[JDS60R]

Anytime a engine shows low compression you want to do a leakdown to find all the causes of leakage from the cylinder.

This would let you know how many things are leaking. Then you can decide what to do (replace gasket, repair valve seats, replace motor etc)

As you still have a compression issue - If it were in my shop we would do a leak down and tell you what we found. Based on how many things are leaking and the cost to repair we would make suggestions.

If it came to needing a motor rebuild you would be better to replace it rather than rebuild it. If you chose to rebuild it you need someone qualified to rebuild a motor. You are dealing with critically small tolerances and therefore the tools and skills used should be top notch. Not only does it have to be rebuilt correctly - It has to be tested and installed correctly.

Check out the cost of a used motor at Erie above or at any salvage yard with www.car-parts.com
Erie gives a nice long warranty that most salvage yards won't offer ( they give short ones)

[omojamie]

I guess my real question at this point is, should he have been able to factor in the ring/compression problem before doing the head gasket repair?

Knowing that, I would have done something else (new engine, new car, etc.).

[JDS60R]

Yes- if a leakdown test was done before the repair you would have been able to find all of the compression leaks the motor had.

At this point you do not know what is wrong with the car because a proper test has not been done.

You may have a bad valve, bad rings or bad head gasket. (Again - right now you do not know what is wrong)
Get it tested properly by a knowledgeable mechanic or an engine builder so you can figure out what is wrong before condemning the motor.

Get a leak down test and share the results.
It should cost less than $100

[mdempst_79]

Good afternoon,

Reading this a couple things come to mind...

Piston rings don't just go bad like a light bulb, they slowly disentigrate until you have no power, oil burning etc.. You would have known before this repair job. Rings can be tested easily by doing a compression check dry, and then checking again with a little drab of oil down the plug hole. If it shows a good improvement, then you need rings. If it is still low then its headhasket or bent valves.

I would have to say at this point a leakdown test is the only way to know for sure instead of guessing and wasting time. With a headgasket repair something as simple as pinching the gasket on a corner or an issue with the dowel pins that locate the head (ie. missing or bent) can cause interference when the head tries to seat flat with the block causing leakage of compression / oil / coolant.

Another possibility is bent valves, as they can get bent if someone puts the camshaft in without making sure the pistons are down where the valves are pushing down.. tighten the cams down and all of a sudden you have a bent valve or more!.

Take it back to the mechanic, A volvo should run forever and not need to see the scrap yard.

[boosted5cyl]

Sounds like the mechanic is a chancer and made some sort of a royal cock-up. You dont even need to do a "leakdown" perse. Just put each cylinder at TDC and smack 100psi of air pressure down the plughole. You'll hear it escape from wherever the leak is. Some leakage is perfectly normal, but if it sounds like a wind tunnel in the inlet or exhaust manifolds or the crankcase\PCV then thats where the leak is.

Its possible its the rings, but unlikely IMO.

[omojamie]

I know you're all on the edge of your seat, wondering how this will end. So here goes.

The mechanic said he was sorry, but couldn't figure out what went wrong. He gave me a partial refund and said the car ran rough, but he had put 'restore' in the oil and maybe that would help. "Drive it for a week or two and let me know how it is."

Well. It did run smoother at higher speeds. I drove it for less that an hour total and it started smoking like crazy. Then the oil light went on. I was close to home so I pulled into the drive and there she sits. No oil. No real resolution.

and so it goes.