91 ls400 Overheating
05-12-17, 02:04 PM
#1
Driver School Candidate
Thread Starter
91 ls400 Overheating
I'm in Florida - it's high 80's and 90's these days.
New fan relays and new temp sensor at bottom of ratiator.
Both fans come on when ac is on and temp goes above 180deg.
No air in system.
No leaks.
Clean, fresh fluid in system.
When cold, runs up to 180 deg and stays steady for a few miles, then slowly starts to creep up, with or without A/C on.
No leaks and no air in system.
Depending on load (speed / temp) the temp will climb up to about 200 or 205 and hold there. If I take it to 65-70 it will go up more.
Turning on the heater brings the temp right down to 180.
I'm thinking the 27 year old radiator is just worked out....
Any thought?
Thank you!
/Don
New fan relays and new temp sensor at bottom of ratiator.
Both fans come on when ac is on and temp goes above 180deg.
No air in system.
No leaks.
Clean, fresh fluid in system.
When cold, runs up to 180 deg and stays steady for a few miles, then slowly starts to creep up, with or without A/C on.
No leaks and no air in system.
Depending on load (speed / temp) the temp will climb up to about 200 or 205 and hold there. If I take it to 65-70 it will go up more.
Turning on the heater brings the temp right down to 180.
I'm thinking the 27 year old radiator is just worked out....
Any thought?
Thank you!
/Don
05-12-17, 02:25 PM
#2
how do you know you do not have air in the system? how was it bleed? in my opinion there is still an air pocket in there, as my experience it takes a while to bleed the coolant correctly. I like to prop the front end of the car up and have the top of the t-stat housing bolt off (not the rad cap) and hold the engine RPMs while a funnel full of fluid sits on the neck. it took about 20 mins to get all the air out! of course have the heater on full blast when doing this.
also check for any obstructions in front of the radiator and in between the ac condenser! lastly, when was the last time the t-stat was replaced? make sure the bleed jiggle hole is at the 12 o'clock position when installing.
also check for any obstructions in front of the radiator and in between the ac condenser! lastly, when was the last time the t-stat was replaced? make sure the bleed jiggle hole is at the 12 o'clock position when installing.
05-12-17, 10:25 PM
#3
Now I will need to check it out. But on modern cars 200 to 205 is NOT running hot. Most are set to run at 220 or around there, its an emissions thing, and besides for efficiency hot is better than cool. So going over 180 is no big deal.
05-13-17, 07:12 AM
#4
Driver School Candidate
Thread Starter
how do you know you do not have air in the system? how was it bleed? in my opinion there is still an air pocket in there, as my experience it takes a while to bleed the coolant correctly. I like to prop the front end of the car up and have the top of the t-stat housing bolt off (not the rad cap) and hold the engine RPMs while a funnel full of fluid sits on the neck. it took about 20 mins to get all the air out! of course have the heater on full blast when doing this.
also check for any obstructions in front of the radiator and in between the ac condenser! lastly, when was the last time the t-stat was replaced? make sure the bleed jiggle hole is at the 12 o'clock position when installing.
also check for any obstructions in front of the radiator and in between the ac condenser! lastly, when was the last time the t-stat was replaced? make sure the bleed jiggle hole is at the 12 o'clock position when installing.
I will try again while parked with a nose-up attitude.
Also, I failed to mention that I had also installed a new 180 deg thermostat as part of my attempt to correct the temp rise.
Still - it nails the 180 deg after warming up, and holds like a rock for about 3-4 miles, then slowly starts the creep up.
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billydpowe
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