1997 Chevy Monte Carlo Overheating

JIM7153

MEMBER
1997 CHEVROLET MONTE CARLO
6 CYL
FWD
AUTOMATIC
10,900 MILES

My 97 Monte Carlo with a 3.1 overheats and and it appears to be building up pressure and stopping all water flow, or could it be the water pump. Replaced the thermostat and at slow speeds (under 45 miles per hour) the car will heat up to about 240 and then the thermostat will open. Drops to about 180 and the repeats this process over and over. At Interstate speed overheats within 3 miles and the thermostat appears to not be able to open. There is no heat coming out of the heater when the car's temperature rises

Wednesday, April 15th, 2009 AT 8:52 PM

3 Replies

EUGENE123

MECHANIC
273 POSTS

I had the same problem with the same motor, whats happening is there is air in your coolant lines and when the air hits the thermostat the car shows that it is getting hotter, then when the coolant comes and breaks through the air it shows that the car is cool again and you get your heat back. To fix this bleed your coolant system and get all air out of coolant lines

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Wednesday, April 15th, 2009 AT 10:57 PM

JIM7153

MEMBER
2 POSTS

I've had this car to two mechanics who have "said" they have completely purged the cooling system. After the first one, I got a whole 5 miles at Interstate speed driving before it overheated and the same after the second guy looked at it.

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Thursday, April 16th, 2009 AT 6:46 AM

EUGENE123

MECHANIC
273 POSTS

Some how air is getting into your coolant lines, this could happen through a hose or a gasket being blown, because if they are completely bleeding all air out of the coolant system then you drive it and it gets hot again some how air is getting in. Check all hoses and lines for holes or leaks, if all good you may have a head gasket or intake gasket blown and it is letting air in

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Friday, April 17th, 2009 AT 2:29 PM