Question about 1995 Pontiac Bonneville

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My 95 bonneville is losing coolant and getting hot. Could it just be the thermostat?

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More info would be needed to accurately assist you. the bonnevilles typically had a 3.8 liter engine that had a liquid cooled throttle body assembly. it was common for the gasket between the throttle boty and upper intake manifold to leak. this leak if left unattended for extended period of time could result in low coolant levels, therby causing it to overheat....any time any vehicle is wise to replace the thermostat as it can fail as result of overheating....the throttle body is the first component on engine after the large rubber hose of the air filter housing attaches to the engine

hope this helps

Posted on Aug 03, 2010


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I have a 98 Bonneville, the heater/defroster is blowing out cold air. I drove around for 30 to 40 minutes checked the radiator and it was cold to the touch. could it be the thermostat

The dash gauges are notoriously inaccurate. But it is possible that the thermostat is stuck open. Does the upper radiator hose get hot after engine warmed up? Also feel both heater hoses-when engine is warm, both should be hot-indicating the coolant is circulating through the heater core. If heater hoses are hot, and you still have cold air, the temperature blend door on the heater case may not be operating.
Try a new thermostat and see if engine warms up faster and better.

Dec 10, 2013 | 1998 Pontiac Bonneville

2 Answers

My heat temperature gets hot when idling,when I'm driving a distance my temperature hand drops to the cool side.

Sounds like a bad thermostat. also make sure coolant if full but this is a stuck open t stat

Dec 20, 2012 | 1995 Pontiac Bonneville

1 Answer

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Watch the temp gauge when the electric radiator fans come on. The temp sensor that controls when the fan comes on may be faulty.

Oct 11, 2012 | 2000 Pontiac Bonneville

1 Answer

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Possible blown head gasket? Pressure coming from the engine combustion. Remove spark plugs and check for coolant coming out of the cylinders. Hope this helps!

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1 Answer

95 caprice heater not blowing hot air, hissing when off. blower is working at all levels. not a sign of the resistor going out. just isnt blowing any heat. not losing any coolant.

The thermostat could be stuck open or the heater core or radiator could be clogged or it could be a faulty heater control valve.I would flush the coolant sytem out with prestone super flush and put a new thermostat in it first.

Jan 24, 2012 | Cars & Trucks

1 Answer

Heater blows out cool air only

Could be a stuck thermostat... or low coolant level. feel hoses going to heater core, if only one is hot while car is warmed up. i would say the heater core is plugged because this is where you get the heat for inside of car ! hot coolant goes through heater core and a fan blows it out to heat inside of car. if both are hot then the heater core is ok.

Oct 20, 2011 | 2000 Pontiac Bonneville

1 Answer

95 cutlass supreme coolant circulates fine idleing than while driving loses heat and coolant goes in overflow

try by changing the thermostat. if it sticks closed, coolant will be deverted to buy pass hose will not heat up. have a good one !

Dec 15, 2010 | 1999 Oldsmobile Aurora

1 Answer

Coolant wasn't getting hot enough changed thermostat now service engine light will not go off

you need to have the codes check to see if it is related to what you changed,Autozone checks codes for free.

Jan 19, 2010 | 2001 Pontiac Bonneville

1 Answer

My car run good but when it get hot it shuts off an i got to wait for the car to cool before cranking it up again what could that be

First, you've got to find out why it's getting HOT. Is the water/coolant leaking somewhere and why? Is it the thermostat or water pump leaking that makes it get HOT? Is the water circulating in the radiator? That's what we must know. Good Luck !!!!

Sep 09, 2009 | 1995 Pontiac Bonneville

2 Answers


You may want to try checking the fans. I have a 95 ss with the same problem. If you disconnect the MAF and then start the vehicle the electric fans will come on. Try driving it like that. That will atleast narrow down your search. If that makes it run cooler then its most likely a problem with the fans. Either a relay or fan switch. Blown head gaskets will usually result in the coolant and oil mixing. Check your fluids for signs of that. I have also read that the radiator cap not sealing properly can cause the coolant system to lose pressure. This reduces the systems ability to circulate the coolant causing it to run hotter. Thats an easy fix. I have not fixed mine yet. I just havent had time. That should be a good place to start. As far as getting a new engine or head gasket they are both really expensive fixes so try any other way u can to fix it first. Hope this helps.

Feb 03, 2009 | 1995 Chevrolet Impala

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