How do you diagnose a bad thermostat on a beetle?..seems impossible-

ever replaced a t-stat on a beetle? no one has.

I have jammed the air outlets open on a Corvair. I didn't know VW Beetles had thermostats. They had boxes around the exhaust for cabin heat.

they always worked well wide open when hot and if not fully closed when cold you never cared as they came up to temp real quick with little stumble if any , remember the long windups, ran good about 4 bolts to remove engine also

Yes between the No.3 and 1 clylinder is a coily little buddie that controls the t-stat flap....they don't work, and are removed or fall off.

The trick is getting more air flow back there. You can purchase hindges that keep the top of the engine deck lid "popped up" or take the deck lid off. There are also fiberglass cowls you can use to catch more air.

its not a Thermostat..

ill give you 10 for that ronnie cuz you aint going no where talking like that

could I subtract those points given by Jimmy? Admittedly it was the troublesome oil cooler that burned the No.3 cyl, the t-stat is on the other side of the engine, near the No.2 cyl.