1979-1993 & 94 Conv [Subscribe to Daily Digest] |
Adrian,
Check your oil first to make sure it isn't low (no offense meant, had to cover all the bases).
If that's OK, then perhaps the valve tappets (the part which gets "tapped" or pushed down, on top of the valve stem by the camshaft) is going bad. These are hydraulic on 16V SAABs (which all SPGs are), meaning that oil inside them expands them to make them take up the space between the valve stem and the camshaft lobe. If it doesn't expand to fill the gap, then that airspace causes a "tap" sound each time camshaft lobe hits the valve tappet.
At least that's my take on it; I'm no mechanic, though. Someone more knowledgable about tappets is welcome to critique the above info; it won't hurt my feelings and maybe I'll learn something!
[I must confess I don't understand how oil gets INSIDE the tappets! Anyone know?]
Also, consider this possibility (unrelated to valves):
The charcoal canister--on most 16V models--(my mom's 1990 base 900 has this, anyway) has an electrically operated valve to control when the engine can suck in the gasoline fumes which evaporated out of fuel tank, traveled through lines, have been "trapped" by the charcoal in the canister. We have EPA to thank for that.
This valve is called the ELCD (Evaporative Loss Control Device) valve, and usually clicks once or twice per second at idle speed, which is normal. Your charcoal canister is in the driver's side (if in USA) of the engine bay, behind the driver's side headlight. Valve lives on top of canister and has an electrical plug on it.
NOTE: Older 900s, meaning 8-valvers like my '84 900S, don't have this electric ELCD valve. Mine is a simple vacuum operated diaphragm, I think. Hope this helps!
Micah in NC
'84 900S, 220K mi.
'90 900, 67K mi. (Mom's)
posted by 216.77.232...
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