Ed Hall Posted August 28, 2006 Report Share Posted August 28, 2006 Just lately, I've been noticing the engine temperature getting very high then all of the sudden cool off. This morning, it got hot enough to set the red coolant temperature light. The temperature at that point was 250 degrees and after it got to about 253 degrees, it came back down. Seems to me like the thermostat is sticking. The engine temperature normally runs between 210 to 230 degrees. Any thoughts about putting in a cooler thermostat like say a 180. I live in California where sludge build up is probably less of an issue. Link to comment Share on other sites More sharing options...
PAUL T Posted August 28, 2006 Report Share Posted August 28, 2006 I put a 180 (not knowing it at the time) thermostat in when I did my water pump in my 94 Concours. It worked fine until the outside temperature got down below freezing and in the single digits. At that low temperature my thermostat will not let antifreeze in the car get hot enough to heat the inside of the car adequately. When the car was at idle it was warmer inside but when the car was in motion I would lose the warmth. I am going to change out my thermostat to a hotter one before this winter. Link to comment Share on other sites More sharing options...
adallak Posted August 28, 2006 Report Share Posted August 28, 2006 I put a 180 (not knowing it at the time) thermostat in when I did my water pump in my 94 Concours. It worked fine until the outside temperature got down below freezing and in the single digits. At that low temperature my thermostat will not let antifreeze in the car get hot enough to heat the inside of the car adequately. When the car was at idle it was warmer inside but when the car was in motion I would lose the warmth. I am going to change out my thermostat to a hotter one before this winter. Replacing 190 stat with 180 one will result in 10F difference, which is about 5% of the temperature of the warmed up engine. One must be really sensitive enough to feel 5% difference... Besides, the heat you get is proportional to the flow rate of the coolant through the heater core. All other things equal it is dirrectly related to the RPM. The latter is much higher when you move. That said the cabin should get warmer as you drive, and the harder you drive the warmer it gets not because of increased RPM but also because of more heat generated with loaded engine. Sure moving object is cooled down by the wind, but all my observations are opposite to your xperience. Let's see what others have to say/share. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
PAUL T Posted August 28, 2006 Report Share Posted August 28, 2006 All I know was the antifreeze was 50/50 mix and the system was full. I never had the same experience before I changed the old thermostat. I had suspected a plugged heater core but the hoses were hot coming in and out. At about 30F and up there seemed to be no problem, but if it dropped below 15F the car would not heat up inside comfortably. Coolant would heat up to 190F then drop back to 170F +/-. This was even driving 3+ hours at 70 MPH. I had to turn the heater off because cool air was coming out of the vents. I found my old post here: http://caddyinfo.ipbhost.com/index.php?sho...p;hl=thermostat I guess it was a 190 aftermarket thermostat. Link to comment Share on other sites More sharing options...
BodybyFisher Posted August 28, 2006 Report Share Posted August 28, 2006 Just lately, I've been noticing the engine temperature getting very high then all of the sudden cool off. This morning, it got hot enough to set the red coolant temperature light. The temperature at that point was 250 degrees and after it got to about 253 degrees, it came back down. Seems to me like the thermostat is sticking. The engine temperature normally runs between 210 to 230 degrees. Any thoughts about putting in a cooler thermostat like say a 180. I live in California where sludge build up is probably less of an issue. It certainly sounds like your stat is beginning to go or gone. When you take it out look for wear marks on the center valve portion because the spring is cocked 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...
adallak Posted August 28, 2006 Report Share Posted August 28, 2006 All I know was the antifreeze was 50/50 mix and the system was full. I never had the same experience before I changed the old thermostat. I had suspected a plugged heater core but the hoses were hot coming in and out. At about 30F and up there seemed to be no problem, but if it dropped below 15F the car would not heat up inside comfortably. Coolant would heat up to 190F then drop back to 170F +/-. This was even driving 3+ hours at 70 MPH. I had to turn the heater off because cool air was coming out of the vents. I found my old post here: http://caddyinfo.ipbhost.com/index.php?sho...p;hl=thermostat I guess it was a 190 aftermarket thermostat. Paul, If the both hoses are hot (same temp.) the heater core is plugged. One hose should be cooler when the blower is on. Just lately, I've been noticing the engine temperature getting very high then all of the sudden cool off. This morning, it got hot enough to set the red coolant temperature light. The temperature at that point was 250 degrees and after it got to about 253 degrees, it came back down. Seems to me like the thermostat is sticking. The engine temperature normally runs between 210 to 230 degrees. Any thoughts about putting in a cooler thermostat like say a 180. I live in California where sludge build up is probably less of an issue. It certainly sounds like your stat is beginning to go or gone. When you take it out look for wear marks on the center valve portion because the spring is cocked I agree with Mike. There is something inside of a stat ( a wax?) which changes inreversibaly when an engine overheats. It's a good practice to replace the stat when it happens. In your case it happened not once bur several times. BTW, properly working thermostat is more important than its operating temperature (I mean 180 versus 190). The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
Ed Hall Posted August 29, 2006 Author Report Share Posted August 29, 2006 Before doing anything, I decided to check the coolant level and I was surprised to find no visible water in the tank. It took nearly 3/4 of a gallon of water to fill it up. Once I did this, the temperature held constant around 200 degrees. The water level has stayed level all year so I was surprised to see it low. Then I remembered, I was in a horrible traffic jam several weeks ago where the car just sat there and idled for 3 hours in almost 100 degree weather. My fans don't kick in until the temperature reaches about 240 degrees so I'm guessing the water boiled slowly boiled out each time the temperature would peak. If I go into the onboard computer, I can turn on the fans manually but it gets old holding my thumb on the button. Maybe what I should do is wire up 12 volts to the fan with a switch on it so I can turn it on manually the next time I'm in a horrible Los Angles traffic jam. Link to comment Share on other sites More sharing options...
adallak Posted August 29, 2006 Report Share Posted August 29, 2006 Before doing anything, I decided to check the coolant level and I was surprised to find no visible water in the tank. It took nearly 3/4 of a gallon of water to fill it up. Once I did this, the temperature held constant around 200 degrees. The water level has stayed level all year so I was surprised to see it low. Then I remembered, I was in a horrible traffic jam several weeks ago where the car just sat there and idled for 3 hours in almost 100 degree weather. My fans don't kick in until the temperature reaches about 240 degrees so I'm guessing the water boiled slowly boiled out each time the temperature would peak. If I go into the onboard computer, I can turn on the fans manually but it gets old holding my thumb on the button. Maybe what I should do is wire up 12 volts to the fan with a switch on it so I can turn it on manually the next time I'm in a horrible Los Angles traffic jam. Check the level in a couple of days. Plastic radiator side tanks are notorious for cracks. I would replace the stat too. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
epricedright Posted August 29, 2006 Report Share Posted August 29, 2006 Before doing anything, I decided to check the coolant level and I was surprised to find no visible water in the tank. It took nearly 3/4 of a gallon of water to fill it up. Once I did this, the temperature held constant around 200 degrees. The water level has stayed level all year so I was surprised to see it low. Then I remembered, I was in a horrible traffic jam several weeks ago where the car just sat there and idled for 3 hours in almost 100 degree weather. My fans don't kick in until the temperature reaches about 240 degrees so I'm guessing the water boiled slowly boiled out each time the temperature would peak. If I go into the onboard computer, I can turn on the fans manually but it gets old holding my thumb on the button. Maybe what I should do is wire up 12 volts to the fan with a switch on it so I can turn it on manually the next time I'm in a horrible Los Angles traffic jam. If you added 3/4 gallon of straight water, it would be advisable to do a drain and refill w/ 50/50 distilled water and coolant. No telling what your water to coolant ratio is now. Your car will boil over faster with less than 50/50 coolant. I'd replace your thermostat as well, too easy and inexpensive not to. Link to comment Share on other sites More sharing options...
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