Heat flucuation and RPM needle failure

**Vurelis** · 02-08-2009

I have a 1997 GT 3800 model. My engine heat will go from 110 to about 210. It flucuates back and forth. Once it gets up around 210 it will drop quickly down to about 110 and then slowly build back up. It never stablizes. It constantly goes up and down. This is a pain in the winter becuase my heater will flucuate with it. I recently had the air bled out of it. Another problem i'm having is every time I drive the car the RPM guage will quit. If I turn the car off and back on it works again. Sometimes I can feel the transmission surge or pull when the guage stops working. A few times it nearly stalled the car out. Some other problems that may relate to these are my car will run rough around 45 mph in the low part of the gear. Also, once in a great while the car will just stall or quit. Sometimes when I go to start it up I have to crank it and give it gas for a minute or two before it will start. Once it starts it runs fine. I have had the injectors cleaned. Any help or advice would be greatly appreciated.

**TheOtherNick** · 02-08-2009

The RPM gauge problem is more than likely the crank shaft position sensor. That is probably your stalling issue too.

**Blown97** · 02-08-2009

Originally Posted by Vurelis

My engine heat will go from 110 to about 210. It flucuates back and forth. Once it gets up around 210 it will drop quickly down to about 110 and then slowly build back up. It never stablizes. It constantly goes up and down.

Might want to look into changing your thermostat...that could be it. If that doesn't do the trick do a compression check and a coolant pressure system check. You can rent both the coolant pressure tester and the compression tester from Auto Zone.

Originally Posted by 01GTP

The RPM gauge problem is more than likely the crank shaft position sensor. That is probably your stalling issue too.

X2 on this....pretty common!

Let us know how it goes. Good luck!!

**Vurelis** · 02-08-2009

Thanks for the suggestions. I'll have it checked out. I changed the thermostat just before I had the air bled from the coolant. I guess it could be a fualty stat. Any recommendations on a good stat?