1979-1993 & 94 Conv [Subscribe to Daily Digest] |
[Main C900 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: 1988 8-valve head gasket diagnosis request Posted by Saana88 [Email] (#207) [Profile/Gallery] (more from Saana88) on Fri, 1 Sep 2017 19:07:03 In Reply to: 1988 8-valve head gasket diagnosis request, Marko, Tue, 22 Aug 2017 12:04:51 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Hey, Marko,
Back in 2000 the head gasket on our/my now departed 1988 900 failed after the belts departed at speed and the engine overheated due to its water pump no longer turning.
The car would vomit coolant out the expansion tank cap around ten minutes after shutting it off.
Your tractor-like running symptoms sound like the classic 8 valve idle control valve failure. The valve functions with a bi-metallic spring. That's right, toaster technology controls the idle speed on your car. If it sticks shut, you will have to hold the throttle open for the first few minutes of running, depending on how cold it is. If you pull the idle valve tubes and shine a light through, you should be able to see an odd-shaped opening. If not, it is stuck shut. A temporary fix is to spray your favorite solvent (carb or injector cleaner, penetrating oil, it's up to you!) to see if you can free it up. Sadly, if it repeatedly sticks shut, you'll need to replace it.
Don't forget that the cold start injector functions like a fifth fuel injector. Despite its young age, you may want to check it for leakage.
My warm-up regulator's bolts had been stripped; it depends on direct conduction between itself and the thremostat housing. Until I fixed that, the car ran poorly until warm. Check the function of your thermoswitches.
My car's temp gauge also jumped around, like it had a nervous twitch. A new gauge sender and a fresh end on the gauge sender wire fixed that. Bad engine block grounds will also interfere with that signal and a whole host of other things.
You may want to pull the spark plugs and see if they are wet. Maybe try to stick something into the cylinder in an attempt to draw out any liquid that may be in there, like one of those fancy-pants oil change suction pumps, or a bulb syringe. If you disconnect the ignition first (very important step!) and turn the engine over by hand, maybe half a revolution at a time (alternately putting each cylinder into compresion) then testing for infiltration, you should have your answer.
I also recommend fuel injector seals, if you haven't already done them.
You have my envy. I miss that car dearly. New York's addiction to road salt did it in. I had to retire the car in 2010 at 235k after most of the body near the rear suspension weakened to the point it would not pass inspection, after doing auto-to-manual in 2002, then proceeding to replace most of the parts you mentioned through 2008. If I ever feel like picking up another project, it will be a 900. For the time being, my convertible will occupy all of my time and effort, and then some.
I hope this helps, and please keep your car in good shape.
->Posting last edited on Fri, 1 Sep 2017 19:16:01.
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.