I have a 1987 non-turbo. The clutch starts to slpip after about 30 minutes of driving when it's warm out. When I have driven it in the winter cold the clutch won't slip for hours. I'd hate to replace the clutch and find out it's something else. I've had clutches go before iin other cars and temerature didn't mattter at all. Help somebody??

 

Try this. Get it into 4th or 5th gear at a relatively slow speed, say about 40mph. Now, floor the throttle. Did the clutch slip? Mine did this. It wouldn't slip in the low gears, but it would in 4th & 5th at lower speeds. Turned out to be the clutch slave cylinder. I put on a new one, and the problem has been gone for 3 years now. Beats me what was wrong with the old one, or why it behaved like that, because it doesn't make any sense. I took it apart and it looked fine, but something was causing it not to release fully, and it allowed the clutch to slip. At less than $50 for the part, it's worth a shot. Maybe change the clutch master, too, while you're at it.