Car isn't running at the right temperature......

Sometimes my car with not run at the right temperature, it will run a lot hotter, but not in the red. But sometimes it seems like the thermostat kicks in and the temperature will rise, then it will drop off down to normal. I don't know what it going on. I have a 92 taurus gl. sedan. We just places the thermostat, water pump and major hoses. Any suggestions

Did it act the same way before you replaced the thermostat? If so here is my theory. If you are in city driving, the electric cooling fan behind your radiator must kick in to cool the engine. Let the car sit still and idle with the hood up while watching the temperature guage, see if your cooling fan kicks in just before the engine starts to cool down and stays off while the temperature climbs. To further test this go out on the open road, say 50 mph or faster, and see if your temperature stays fairly steady. Some of the early generation 1 taurus's fans didn't kick in until the temp guage needle reached about 3/4 of the way over. (Your 92 would be a generation 2 taurus.) I may be way off base, but that's my guess.

Where did you get the thermostat??? Is there any chance that the one you have in her now is a higher temp stat and it doesn't open up like the other one did. Recheck your part number w the application to make sure. Just something to check. M.

I checked to see if the fan kicks in and it does. When the temp. gauge kicks back down, then i get heat in my car. When it doesn't I don't have any heat at all, it will just blow out cold air.

Sounds like you might just have an air pocket in your cooling system. Remove the radiator cap when the cooling system is cool and check the level. Don't just look at the level in the overflow tank, if the level in the system isn't full, it won't be able to pull coolant out of the overflow tank.

If the original thermostat had a jiggle valve (small little ball bearing valve in the thermostat) the replacement needs to have one too. The jiggle valve needs to be oriented at the 12 o'clock position.

Your car may also have a air purge/bleeder valve on the cooling system too which would allow you to bleed the air from the system.

Air in the cooling system could explain the cold air blowing from the heater core (full of air rather than circulating coolant) and the drastic temp changes (air against the coolant temp sensor reads cold, but once the coolant gets warm enough to expand and comes in contact with the coolant temp sender, the gauge reads accurately and the fans kick in because the coolant contacts the coolant temp sensor too and kicks the fans on.

-Rod