higgnoid Posted July 12, 2004 Share Posted July 12, 2004 I'm concerned about my 1990 Loyale (155k miles, 4wd, standars trans) The temperature guage is allways cold. The needle climbs just a tiny bit after running it hard but it never really gets off the bottom. I suspected the thermastat so I looked into it. Pulled the old t-stat out in the morning when the engine was cold. I suspected t-stat to be stuck open but no, it was shut. I had a new one (180 deg) so I replaced it anyway. Drove the car this morning and same situation on the temp gauge - cold. I assumed that if the gauge wasn't working the needle wouldn't move at all. It moves just a hair and drops when I shut off the engine. Should I be concerned about running the engine too cool? Could it be a bad sensor and maybe I wouldn't even know if it was overheating? If so, how can I check the temp sensor and gauge? Quote Link to comment Share on other sites More sharing options...
EmmCeeBee Posted July 12, 2004 Share Posted July 12, 2004 First things first. Did you check the coolant level, make sure the radiator is full? After you run the engine, is the radiator hot? 180* is just at the temperature where you can put your hand on it for 1 second before primal scream. If the thermostat is opening, you should feel the flow in the radiator hose. You can even start the engine with the radiator cap off (only take the cap off when it's cold), warm it up, and when the thermostat opens you'll see flow in the radiator. Checking the thermostat is the next logical step, you're on that one. Check it by putting it into a pot of water on the stove and boiling it, using a thermometer to watch when it opens. If it opens too soon, you'll run cold and your gas mileage will suffer; probably foul your plugs with rich mixture, but no major damage (at least as compared to overheating). If you really got a "cold running engine" -- one that dispels heat as fast as it generates it -- you've got something almost as valuable as cold fusion. The heat has to be going somewhere. If it's going into the coolant, then you've got a bad temperature sensor or gauge. If it's not going into the coolant, then your radiator is low, or you got worse problems..... :-\ -- Mark Quote Link to comment Share on other sites More sharing options...
Bill90Loyale Posted July 12, 2004 Share Posted July 12, 2004 Could it be a bad sensor and maybe I wouldn't even know if it was overheating? If so, how can I check the temp sensor and gauge? The FSM says that the test for the thermosensor is to put it in water at three different temperatures and measure the resistance with a multimeter at each temp. 14 degrees F = 7 to 11.5 k ohms 68 degrees = 2 to 3 k ohms 122 degrees = 700 to 1000 ohms "If the resistance value is too much out of these ranges, replace the thermosensor with a new one." The Haynes check is an on-engine check and is simpler: "Disconnect the electrical connector at the sender and connect an ohmmeeter between the sender's terminal and an engine ground. When the engine is at ambient temperature (122 degrees F) resistance should be 130 to 170 ohms. As the engine warms up, the sender's resisance should drop, and at full operating temperature (212 degrees F) should read between 25 to 30 ohms." If you remove the sensor, do it when the engine is cold. Be ready to catch some coolant. Use PTF tape on the threads to reinstall or put in a new one. Quote Link to comment Share on other sites More sharing options...
archemitis Posted July 12, 2004 Share Posted July 12, 2004 i bet its the guage, or the sender not workin correclty. see if the car has hot air, from the heater Quote Link to comment Share on other sites More sharing options...
aprilspies Posted March 25, 2005 Share Posted March 25, 2005 same problem in my 90 loyale. no heat either. sometimes lukewarm at best. just had a new water pump put in...no leaks under dash... replaced thermostat and it is functional...also got a flush and still no heat like before my water pump went. any ideas? i bet its the guage, or the sender not workin correclty. see if the car has hot air, from the heater Quote Link to comment Share on other sites More sharing options...
idosubaru Posted March 25, 2005 Share Posted March 25, 2005 no heat can be cured by pulling the hoses to the heater core and flushing it out at the firewall. use a garden hose and blow the heater core out. lots of dirty water and junk will come out and your heat will work just fine. if the gauge reads lower than normal...turn the heater on. if the heat works, then the gauge is not functioning properly for some reason (either the gauge has problems or it's getting bad information). if there is no heat, then the coolant and engine may actually be cold. which would indicate a bad thermostat which you're telling me is new, so that's likely not the case. Quote Link to comment Share on other sites More sharing options...
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