I recently noticed that my Bonne was running hot when pulling a hill - I thought nothing of it since all is under load w A/C, and temps have been about 90 here for some time. Then today I was at idle and it normally runs right at the top of the guage - it was running hot so I popped the hood and saw that the fans were spooling down. I sat there and watched and saw them spool back up when the temp gauge creeped over the halfway point between the top and the red. I have no coolant leak and the level has remained steady for some time and it has never overheated on me -- yet. Does anyone know if there is a temperature sensor wired directly to the fans? How about what temp they are supposed to come on at or should at least 1 or both be running at all times. What about a bad thermostat?? It has the supercharged engine. The tranny fluid is still pink and doesn't smell burnt, and I had the oil changed 700 miles ago and the level is fine - I have just over 120K of well maintained miles.

I Have The Same Problem With The Gauge Bouncing Around From Have To The Red Mark-the Car Never Overheated Before But I Could Feel The Engine Loosing Horsepower When Hot...the Car Feels Sluggish

I Have The Same Problem With The Gauge Bouncing Around From Half To The Red Mark-the Car Never Overheated Before But I Could Feel The Engine Loosing Horsepower When Hot...the Car Feels Sluggish

I put a 185 degree thermo in mine. Stays just to the left of the top now.

There is a sending unit in the thermostat housing. It may need to be replaced. The fans are suppose to kick on around 130 degrees.

If you visit the forum www.bonneville.com and take a look around, you'll notice the majority of them encourage getting a 185 and drilling a .125 inch hole in it. I tried this on mine, and it did work great, except for the fact it gets cold here in the winter, so I grabbed a 195 and use it when the climate gets colder (even got a drilled one). These engines (supercharged) get pretty hot, and have read where they switched back to the lower thermostats on the 96 (97 ?) models. I've also seen the thermostats that come with a spring loaded one way plunger (about the .125 size) that do the same thing, thats why I trusted what they were saying. But some may disagree.