thermostat quesiton
02-06-2016, 10:52 PM
#1
Le Mans Master
Thread Starter
thermostat quesiton
when my car is warming up, it does as you would expect, it warms to a certain point, then when the thermostat opens, it drops back down. What's strange is that it warms back up again, then the temp drops, and this cycle continues for a good while as I'm driving along. Has anyone heard of this before? No the car doesn't have an electric fan that's constantly kicking on to cycle the temp back down.
02-06-2016, 11:45 PM
#2
Le Mans Master
Member Since: Oct 2002
Location: Las Vegas - Just stop perpetuating myths please.
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My dodge w/Cummings does that. Used to worry me at first but now at 250k mi and a new T-stat ijust watch it happen. All kinds of things can happen inside the coolant sys. I would only worry if temp gets over 212*F.
02-07-2016, 03:41 PM
#3
check or change your radiator cap,a bad one will do that.
02-07-2016, 04:36 PM
#4
Instructor
Very possible that you have an air pocket in your engine coolant. Try running th engine with the radiator cap off for about fifteen minutes, it might chase the air out. Do not run it to full operating temp. If you do the coolant may boil as the pressure is reduced.
02-08-2016, 12:24 PM
#5
Melting Slicks
Fill the rad up to the top, fill the recovery bottle to full line. Make sure the overflow hose is in good shape w no leaks
And replace rad cap.
02-09-2016, 07:50 PM
#6
Race Director
when my car is warming up, it does as you would expect, it warms to a certain point, then when the thermostat opens, it drops back down. What's strange is that it warms back up again, then the temp drops, and this cycle continues for a good while as I'm driving along. Has anyone heard of this before? No the car doesn't have an electric fan that's constantly kicking on to cycle the temp back down.
If it is...then what 'mikem350' wrote in the above post is CORRECT.
AS he wrote:
Fill the rad up to the top, fill the recovery bottle to full line. Make sure the overflow hose is in good shape w no leaks
THIS IS IMPORTANT!!! Especially the overflow reservoir hose from the radiator to the coolant reservoir being GOOD and NO LEAKS.
And...make sure that your radiator cap is tested OR replace it with a 15 lb CLOSED SYSTEM cap. It is IMPORTANT that it is a CLOSED SYSTEM cap.
DUB
02-15-2016, 12:09 PM
#7
Racer
when my car is warming up, it does as you would expect, it warms to a certain point, then when the thermostat opens, it drops back down. What's strange is that it warms back up again, then the temp drops, and this cycle continues for a good while as I'm driving along. Has anyone heard of this before? No the car doesn't have an electric fan that's constantly kicking on to cycle the temp back down.