I have a '95 Bonneville SSE with 147000 miles. So far I've replaced many things that have to do with the cooling of the engine, including the thermostat, temperature sending unit, water pump, and I think the inner engine temperature sensor. I live in florida which has lately been hot and I've noticed the car getting up to the start of red on the coolant temp gauge. This happens especially in lots of stop and go traffic and when it sits idle for short periods of time. Normally the temp is pretty good mostly maxing out around 230 or 235 before going down slightly to 220 or so. Sometimes it'll even get up to 240 and all of the sudden drop very quickly to 200. I let the car sit idle until it got to around 240 or more and lifted the hood to find the fans not running. This leads me to believe that the fans are either not working or only want to work when they feel like it. I've burped the car on one occasion.

I thought about completely bypassing the stock switch and installing my own adjustable fan switch on which would allow me to set it to the desired temperature and turn the fans on. However I'm concerned this will cause the check engine light to come on.

My oil pressure is normal so no problems with the oil pump.

I'm going off to college in an even warmer area in august which could be up the 100 degrees and I don't want to even think about having a car that already runs hot in an environment like that.

any suggestions or help would be great, because I'm really at a loss here.

my bro had the same problem with a monte ended up having blown head gasket

I believe you have 2 temp sensors. One in the LIM under the thermostat housing, and on in the radiator. If one isn't reading right the fans may not come on. The fans should come on at 126* Try turning on the AC, that should make the fans come on.

They do turn on but I need them to run when I'm not using the A/C too. The signs of a blown head gasket are fairly obvious and I seem to have no visible oil or coolant leaks on the engine block. I have a small amount of oil on the block and manifold cover but I believe that'* from something else.

Almost never see blown head gaskets on these engines. Unless you really over heated it. Your engine if overheating because of the fans not turning on. I would check the ECT sensors. One may be reading wrong.

Could you happen to quickly tell me where both are located. I may have replaced one already.

Thanks again everyone, but especially DANTHURS. You always seem to help me out here.

One should be right under the thermostat housing. And I believe there is another one on the radiator on the passenger side.

Great thanks a lot. I'll check into those and most likely replace them. I'll let you know how it goes.

Number 515

The one on the rad on pass side is coolant level.