97 Pontiac Trans Sport engine temp increase

[pk9073]

My 97 Trans Sport Temp gauge has started to read hotter than normal. The Temp reading has always been rock steady at the first hash mark just above the first quarter division of the Temp gauge. It will now run up to about midway/210. It does smell hot when this happens. No, I do not continue to drive at this point. No, it does not redline and no warning lights come on.

I can turn the heater on full blast to vent the heat through the passenger compartment and the Temp will go down to near normal level.

The Temp will occassionally revert to normal near normal on its own for a few miles or even an entire day or two once in a while.

Do these symptoms suggest a bad Thermostat or a bad PCM?

None of the fan relays have been replaced. They do turn on when the A/C is on.

The engine is a crate engine with about 6,500 miles on it. The original engine had the crankshaft break at about 136,000 miles.

Thanks
pk9073

[maxwedge]

Scan it and se ewhat the actual temp reading is, fans come on at about 222-225 F, 210 is not a problem.

[Viala]

few years ago , I had a problem of heat
On my TS 1993 there are 2 radiators in front and between it was full of dust, with water under pressure I cleaned it , and after it was OK

[LMP]

THe fact that you can lower the temperature by running the heater full blast points to a heat transfer problem with the radiator, either on the air side or the coolant side. THe engine as described is definitely not a prime suspect. So check as Viala suggested for air clogging. On the other side, when water containing mineral salts is used to top aradiator or as a mix with antifreeze, a very thin scaling deposit in radiator can cut heat transfer dramatically...and one can spend tens of dollars on magic cleaners....practically it ends up only a new radiator fills the bill (in industrial plants, this problem is handled with acid cleaning).
But after all that dramatization....simply said....begin by checking the tubing between engine and radiator: rubber happens to peel on the inside and block the flow. . And, for a 0 $ test, just remove the thermostat and go for a test ride.....and the thermostat can be checked on the kitchen range in boiling water with a candy thermometer.....

[pk9073]

Thanks to all for the advice and suggestions. I will try each and see what happens.

Originally Posted by pk9073

My 97 Trans Sport Temp gauge has started to read hotter than normal. The Temp reading has always been rock steady at the first hash mark just above the first quarter division of the Temp gauge. It will now run up to about midway/210. It does smell hot when this happens. No, I do not continue to drive at this point. No, it does not redline and no warning lights come on.

I can turn the heater on full blast to vent the heat through the passenger compartment and the Temp will go down to near normal level.

The Temp will occassionally revert to normal near normal on its own for a few miles or even an entire day or two once in a while.

Do these symptoms suggest a bad Thermostat or a bad PCM?

None of the fan relays have been replaced. They do turn on when the A/C is on.

The engine is a crate engine with about 6,500 miles on it. The original engine had the crankshaft break at about 136,000 miles.

Thanks
pk9073

[pk9073]

My 97 Pontiac Trans Sport temperature increase was due to blockage in the radiator. I installed a new radiator this afternoon. I ordered the new one online, paid for it, and, believe it or not, it was delivered to my front door about 30 minutes later! It is hard to get a pizza delivered that fast!

Thanks for the great advice.

Regards,
pk9073