[cassonian]

On my way to work on Tuesday morning and just about to exit the dual carrigeway when my car suffered what I can only think to be head gasket failure.

Suddenly a (huge) cloud of white smoke appeared behing me and the guy following me in a BMW must have thought he was following some kind of James Bond!

Managed to limp to work (only about 1/4 mile) but now the car struggling on idle and has lost water from header tank. There doesn't appear to be any water in the oil so can only assume it is mixing with exhaust gasses?

Any help or hints with replacing gasket appreciated! Ian. :evil:

 

[shaverjeff]

check the cylinders

im not an expert here but the water could be leaking directly into the cylinders and burning running down into the oil pan. id pull a spark plug and manually turn the engine over if there is water there it will shoot out. ps. ive never done this on a saab but many a time on other cars.

 

[Matthew]

Any help or hints with replacing gasket appreciated! Ian. :evil:

Bag and tag all parts. You'll have forgotten what they're for when you have to put them back. If you have a digital camera, then take loads of photos - they may save your bacon.

If you have the time, then strip the head and take it to an engine shop to be hot-tank cleaned. Have them check the head for flatness and cracks, install new valve guides (if necessary), valve stem oil seals and gently lap in the valves (remember they're stellited).

You could also have them hot-tank the dismantled throttle body, and inlet manifold. I'm always astonished at the amount of crap inside the manifold's plenum.

Remember also to tag the valve gear so you can put them back where they came from (valves, lifters, springs, collets, bottom washer and top retainer). If you strip the head you'll need to buy valve spring compressors - I bought Sykes Pickavant compressors (part number 03950000), £36 from Halfords. They have a vertical capacity of 35-142mm and a horizontal capacity of 152mm.

Above all - give yourself open-ended time. Don't rush. Check anything you're not sure of.

Oh, and of course don't drive the car. Do you have breakdown cover?

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[cassonian]

Thanks for that.

I can recover it myself with a car trailer, it is only about 15 miles away at my work so can pull it back on a transporter with my 99!

I know this is a how long is a piece of string question but how long will the work take to do a straight swap without too much tinkering? A mate of mine is a mechanic and may be able to do it in his spare time, with full garage facilites. Do you reckon a full day would see it off with 2 of us on the case.

Can it be done with the engine in situ?

 

[Matthew]

Isn't 900 + trailer slightly over the towing weight for a 99?

The engine stays where it is for the headgasket job. Book time is ten hours, so yeah it's possible to finish the job in one day. Munki and I did the headgasket on his NG900 easily in a weekend. At least you have the light evenings now.

You could save time by not removing inlet or exhaust manifolds, although it's good practice to repalce both gaskets at this time. The head with manifolds would be very heavy, but two of you might be able to lift it - if not, you could use an engine crane.

I'd buy the gasket set from Saab, or just the headgasket on its own if you're not going to replace the manifold gaskets. You'll need antifreeze and distilled water, thermostat if that's old, fine emery and a pot scourer to clean the head. It's been a long time since I did a headgasket!

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[cassonian]

Isn't 900 + trailer slightly over the towing weight for a 99?

Think it might be for a 35 year old one! I have the use of my works Merc Sprinter so that will do the trick.

Thanks for the info, will keep you posted regarding progress. Looking at a few weeks time, got to track down a couple of good doors and a bonnet first and do the lot over a weekend with a new front screen also.

Should keep me busy!

 

[Dr Rock]

Took me and a mate a weekend by the roadside to do his T16 head gasket. We kept the inlet and exhaust manifolds on and the turbo and *just* managed to lift the whole lot off and onto a table, with a lot of swearing and grunting going on.

Car is fine now, especially since the previously incorrect timing was corrected .

 

[Matthew]

Car is fine now, especially since the previously incorrect timing was corrected

Important point there: if you remove the distributor, then mark off the its position against the cylinder head. That will be enough to get the car started after the work, but you must time up the engine properly using a decent lamp. The mark method just isn't accurate enough.

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[rob beard]

Head Gasket

I am probably to late to post to this now.

You do not need to remove the exhaust manifold, but do remove the inlet manifold pull it free and tie back with wire to the left inner wing somewhere.

Before you put it all back together I suggest you replace the exhaust manifold gaskets and all the studs and nuts and all new nuts and bolts and gaskets on the turbo

Rob from Derby

 

[jetman]

OUtside of really technical things which your mechanic friend should be fine with, the biggest pain for me on these is usually the two stupid 12mm bolts that attatch the timing chain cover to the bottom of the head.

Air tools are your friend, will cut the time by half or more.

Make sure to wire your timing chain to your windshield wiper so you dont lose it down inside.

Its an interference engine so you only get one chance at getting the valve timing right (Marks are easy to line up)

Put the car up on stands so that you're not leaning over and down the whole time, it kills your back before too long! Unless you're short!

 

[Matthew]

I find a bungee cord useful for keeping the timing chain tensioned and out of the way. If it drops down into the block then it's engine out time

As for timing the engine, there's a line stamped on each of the cam sprockets. Ensure this line is perpendicular to the top face of the cylinder head.

According to Townsend, there are three marks to consider - TDC on the flywheel, stamped mark on the cam sprockets and pointers on the cama/bearings. Align flywheel TDC, get sprocket marks perpendicular and then look at the cams. Apparently those markings can often be out.

However, if you align using the flywheel and cams only, the valve timing can be out by one tooth.

Townsends advice exactly matches my own experience with two cylinder head jobs. On my own T16, the cam marks were out slightly, but on a GM900 the marks were way out of whack. On both engines though, timing was spot on first time.

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