Closed loop operation/or inoperation
Thread Starter
Instructor
Joined: Jul 2007
Posts: 236
Likes: 0
From: Mobile Alabama
Closed loop operation/or inoperation
My 1990 L-98, automatic runs cold all the time - either the thermostat is out or stuck open - just wondering what this might cause - it seems to only have power at full throttle and idles poorly at a red light. I'm going to put in a 195 degree thermostat this weekend as well as clean throttle body and install new filter - car is bone stock. Do I need to do anything special when I drain radiator down to put in thermostat and refill? Do I need gasket for throttle body?
Thanks
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Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
How did you determine it runs cold? Temp reading comes from the sensor mabey it is disconnected or bad. It will cause the car to run like crap if it is. Thermostat stuck will not make it stay cold just a little longer to warm up is all.
Last edited by Redeasysport; Apr 14, 2008 at 04:32 PM.
Thread Starter
Instructor
Joined: Jul 2007
Posts: 236
Likes: 0
From: Mobile Alabama
Only determined by gauges
Both oil & water seem very low - oil lower than water - If I drive hard both will come up some. I have had a LT1 and it ran very warm - this car - I've only had on road for a couple of months and it's been pretty cool down here - never seems to get fully warmed up - could be sensor - I'll check connection but it is both oil and water so felt most likely just never getting fully warmed up. Drove 200 miles on Interstate at 70 and never really got warm but temp was in 40's.
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Team Owner
Joined: Sep 2001
Posts: 62,171
Likes: 1,735
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
check the temperature sensors for oil and coolant
What is the temperature reading on both after about 20min of driving? Stock stat is already 195, thats not your issue, assuming its stock.
Even then, a 160 thermo will let it get just as hot, just takes longer, mine does and the weather here isnt much different from yours.
No SES light is showing?
What is the temperature reading on both after about 20min of driving? Stock stat is already 195, thats not your issue, assuming its stock.
Even then, a 160 thermo will let it get just as hot, just takes longer, mine does and the weather here isnt much different from yours.
No SES light is showing?
Last edited by vader86; Apr 14, 2008 at 04:44 PM.
Thread Starter
Instructor
Joined: Jul 2007
Posts: 236
Likes: 0
From: Mobile Alabama
No light
It's a 90 so nothing but gauge to go by - I'll get sensor's checked - it could be them - car has had a new erg valve put in before I purchased and appears to have a new upper radiator hose - I just assumed someone had taken out the thermostat but it never fails my worst errors are following assumptions.
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Team Owner
Joined: Dec 2000
Posts: 21,094
Likes: 282
From: Phila., PA burbs
The 90-91 gauges do suck, but you can pull up a digital coolant temp through the HVAC unit. Push and hold the up and down buttons at the same time until "00" is shows on the display. Then use the up arrow to scroll to "16", hit the button between the arrows and the coolant temp will be displayed in Celcius. You still have to convert to Fahrenheit, but its a hell of a lot more accurate then the POS analog gauge.
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