Lessons learnt

[rothgar]

I am taking a break as I move into the final stages of finishing Head Gasket repair.

I am to hard part trying to figure out where all those parts I took 2 months ago go.

Gotta say even though I'm a little peeved at FCP Groton for not RMAing my first head gasket when I reported it had stuck to the packing their pictures are remarkably useful.

I do strongly recommend removing the Cam Locking device BRFORE you try to turn the engine over. I am strong enough I was able to turn the engine with it in place and was concerned about some of the noises I heard when I realized my mistake. I hope I didn't do any rear harm. Turned it through 6 rotations without any adverse sounds so I remain hopeful.

Ended up doing a valve/head job on this thing in addition to the gaskets and all the other things that just make sense when you've got the engine open: water pump, timing belt, idlers, tensioners and so on.

One other really interesting discovery for everyone
If you use a typical incandescent shop light replace the bulb with one of those funky Compact Flourescent ones. First of all you reduce your chances of getting burned by the bulb heat plus it looks like these bulbs are more durable than conventional bulbs. If they break though you need to be careful cleaning up (they have a bit of Mercury in them so don't use a vacuum.

I found that Haynes has their heads in a dark place about take out the Exhaust Manifold. I eventually got this to work when I realized that when the EM was all the way tight to the head the Exhaust Front connection could be pulled apart. Otherwise their just isn't any hope.

[Mac_in_MA]

Hey all,

This is a reply (I think) to an old thread, but hopefully some of you are still lurking...

I've got a 94 850 that blew the head gasket as well. Same cause - overheating. In my case, the boots around the spark plugs melted. Is this normal (when it overheats)? The various independents that I talked to, including a volvo specialist, said it "might" indicate lower engine damage, if it got that hot. Because of this I've not been persuing the repair (We bought a newer '98 instead) but if the old one is fixable, I'm loath to junk it. I thought I might try to take the head off, and let the local expert take a look at the pistons to make sure only the head gasket needs fixing, and then.... take it down to one of them to let them put it back together.... (with neatly labelled parts that I'd taken off...)

Is this dumb? The repair guys were saying for them to do the whole job, they'd have to get it apart to see if the lower engine has problems, and by then we've spent half the repair bill..

Any suggestions? Is the lower engine fairly bullet-proof? Have I laid an armor-piercing shell into it?

Thanks,

Mac

[Tatter]

Some universal observations re: turbo; re: head gasket changes.
a) One of home mechanics here related that he carefully removed the carbon from the top of the pistons when he accessed the area. Don't do this unless it's just to remove loose, scaly carbon sheets. (Also, DO NOT remove the 'build-up' of what ever at the top of your cylinder bore unless you are replacing your rings).
Reasoning: (told to me by a mechanic so old that he began work in Salt Lake City on steam locomotives...). Carbon is a great insulator, the higher the heat in your cylinder, the more effecient it works. Yes, you want temperatures below 'melting' for the combustion area, but the incredible insulation provided by a thin film of carbon actually aids in keeping things 'cooler'(... unless you are the edge of an exhaust valve). The 'build-up' at the top of your cylinder bore has been developed with the PERMISSION of your piston-ring excursions; the 'developed' shelf is a much-needed ADDED seal that restricts blow-by.

b) Some areas of the world have added requirements for catalytic converters, eg. California. These requirements were greeted with various design changes to the cats, some are just increased price for the CA-stamp; some are ADDED materials in the Cat itself. So: heads up if you have such cats in your turbo vehicle, because road trouble on a higher milage vehicle goes like this: 1)slightly excessive blow-by of mucky oil => hotter, clogged-cat => back-pressure on the turbo => hot turbo => shot turbo bearings. Mazda's I KNOW go down this path, but so can ANY turbo beast. Highly consider a fouled Cat as the root cause of a failed turbo, shot head-gasket!