coolnesss Posted September 25, 2009 Report Share Posted September 25, 2009 My 2002 ETC is running a little hotter than it should - 215-220 range, with 34k miles. The thermostat doesn't seem to open until 190 degrees, and even then, I see very little movement of coolant in the tank. I've checked the crossover hose and coolant flows from it. The car acts like it doesn't have enough cooling capacity - as if the thermostat isn't opening fully. When I'm on the freeway at speed, it cools right down to 200 degrees or so. What are the symptoms of a partially stuck thermostat? Link to comment Share on other sites More sharing options...
BodybyFisher Posted September 25, 2009 Report Share Posted September 25, 2009 The stat should be fully open at 190, if it were binding it may open later, how old is it You wont see much movement in the coolant tank like you did when you could peer into the radiator The stat can get old and start to bind if you looked at it, you would see the pindle shaft rubbing Check your fans for proper operation Check your water pump belt and tensioner Have your cooling system checked to see if it holds pressure Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
KHE Posted September 25, 2009 Report Share Posted September 25, 2009 I would not be concerned at this point. You note that at freeway speeds, the coolant temp is 200 - perfectly fine. Kevin '93 Fleetwood Brougham '05 Deville '04 Deville 2013 Silverado Z71 Link to comment Share on other sites More sharing options...
John Wicz Posted September 25, 2009 Report Share Posted September 25, 2009 Just to add to the conversation, the factory thermostat is 180 degrees. Link to comment Share on other sites More sharing options...
coolnesss Posted September 25, 2009 Author Report Share Posted September 25, 2009 The system is pressure tested and holds pressure. The thermostat is the original in the car - the car has 34,000 miles and is 7 years old. The water pump belt is tight - but how can I check the tensioner? I sometimes notice a little noise in the water pump area when the car starts up. Is this a symptom of something? Link to comment Share on other sites More sharing options...
BodybyFisher Posted September 25, 2009 Report Share Posted September 25, 2009 The system is pressure tested and holds pressure. The thermostat is the original in the car - the car has 34,000 miles and is 7 years old. The water pump belt is tight - but how can I check the tensioner? I sometimes notice a little noise in the water pump area when the car starts up. Is this a symptom of something? You would need to pull the belt and move the tensioner to see if its binding or hard to move, the spring should apply full pressure to the belt If you are getting noise it could be slipping You might try to put a few DROPS of lube on the pivot point of the tensioner but be careful not to overdue it and get it on the belt or you will have problems Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
coolnesss Posted September 25, 2009 Author Report Share Posted September 25, 2009 I would not be concerned at this point. You note that at freeway speeds, the coolant temp is 200 - perfectly fine. I recognize that, but, at lower speeds, in traffic in town, or going up a hill at slow speed, the temperature creeps up. That is what makes me think it's not getting enough coolant flowing through the radiator. Going up a steep grade for a mile on a hot day, it'll reach 230 degrees, but never goes higher than that. It has Dex-Cool, and the prior owner had the dealer change the coolant at 21k miles. Link to comment Share on other sites More sharing options...
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