The Stovebolt Site Forums The Shop Area Engine Shop radiator/thermostat

I am unable to get my operating temp above 165 degrees even after 2 or 3 different thermostats. they are all 180 degree units and bought from different FLAPS. the only time that the temp will get anywhere near 180 is when sitting/idling for a long period of time and then quickly drops down to 165 when driving resumes.

I am sure that my radiator needs to be recored/replaced as there is some leakage of steam and it is discolored from the leakage.

Is that leak the reason or do I need to look elsewhere?

Chuck

Chuck,

My first question would be..what are you measuring the temperature with? If it's the gauge, it could be way off.

Unless there is some internal bypass through the thermostat housing, that little pellet will not open the stat until it's pretty close to the advertised temperature.

Make sure you are using a accurate instrument to measure the water at the filler neck when it's up to temp.

Stuart

Like Stuart said, check your gauges. I had been fighting with my truck showing hot(210-230)and had changed thermostats 3 different times. Installed new radiator seals, everything you could imagine. New gauges from the Autozone(cheap foreign crap), and finally a friend with a handheld infrared temp sensor showed me the gauges were off by as much as 50 degrees. No wonder I was worried all the time. Oh yeah...the warranty on the gauges had just ran out last week.

A leaky rad may not let it keep the temp, the cooling sysym should have pressure?

I can't think of any typical cooling related problem that would result in too low a operating temperature other than no thermostat or a leaking or bypassed thermostat.

EDIT. Chuck, I looked at your previous posts. On 12/2004 you mentioned a thermostat problem (stuck) and low operating temps.

Stuart

and make sure your temp sender is in the flow of water-fully and not recessed in it's threaded pocket in the head. some senders have a brass threaded insert that does NOT allow the sender to be seated fully thus the pocketed sender does not reflect the correct temp flowing past it.

Stuart,
2004...wow I guess it has been that long of time since this has been going on. At that time I was having the same problem. I did get a bad thermostat at first and that is what threw me for a loop. So after a couple different ones I got one that was opening/closing correctley. I tested them with boiling water in the kitchen.

I am leaning towards the gauge being off and will get my old meat thermometer to test it...but still think that the leaky radiator might not be keeping the right pressure.

Chuck,

The purpose of the pressurized cooling system is to raise the boiling point of the coolant and allow the system to run at a higher temp.

Any problem with the radiator such as your leak or plugged tubes or fins would create a overheating problem. Your problem is inadequate operating temperature...the other end of the spectrum.

The one and only device on a car that is designed to bring that temperature UP is the thermostat. With the gasket in the housing, the thermostat should be held firm between the two halves of the housing. If the housing is all corroded, which it sometimes is, and coolant can pass through somehow, the system is defeated and it's a pot luck deal.

Good luck and keep us in the loop on your progress.

Stuart