OK. If I let the car sit and idle the temp goes to 180-200. If I drive the car at 50mph and the temp does not go any higher than 140. I blocked off about 1/3 of the radiator with a piece of cardboard and it stays at 160. March street pulleys: crank pulley is 5 1/2" water pump is 5". Under drive water pump pulley would be 6". The robert Shaw thermostat has (3) 1/16 holes drilled in it. The thermostat should be closed at 140, so how is the engine staying at 140? There should be some fluxuation if the thermostat is opening and closing.

I am not convinced the system is not being bypassed and defeating the t-stat. The tests in post #19 will confirm or deny that fact.

..gut feeling is the t-stat is not seating closed well or those 3 holes drilled in the t-stat are a wee bit larger than 1/16".

Under cooler ambient conditions you may be getting too much coolant flow through those 3 drilled holes or an unseated thermostat, more than the engine's heat output at that time. This holds true especially under low power cruise conditions where there's minimal throttle action. The engine's heat generation is somewhat proportionate to horsepower output. My money's on a defunct thermostat. Let us know what the end result is..

Is your fan turning on at the proper temp? Or is it running all the time?

And another thought...is the T-stat installed backward? If so, not only will it work "funny", the coolant pressure in the block may be pushing it open when it is trying to stay closed.

You describe perfectly what I experienced in our 2004 envoy. pulled the thermostat and a big chunk of rubber was hung up in it, originally part of the thermostat housing. you have a bad thermostat, replace it, driver you car.

Lots of good feed back here but if this was my car, I would change the thermostat before doing anything else. It is quick, easy, and cheap. You cannot make it worse and if it doesn't fix the problem, you have eliminated one factor that hasn't cost much. :rolleyes::p I think that the present thermostat isn't closing properly so you are getting coolant flow when you don't need it.

Wayne

Pull the t-stat and put it in a pan of water on the stove. Stick a candy thermometer in it and turn the heat up. See what it does.

i had used a thermostat with 4 holes drilled and it would not let the engine warm above 150, about same as yours. replaced with one with 2 small holes and heats up much better. your 3 holes may be too much, depends on size also. course it has been cold out also.

That, coupled with the non-use of the water pump bypass hose (I believe I remember him saying he was not using it) could very well be the answer.

The different methods of getting from here to there are interesting if you stop and consider them. In the end most will get you to the same place but reminds me of how many ways there are to see or interpret things the customer says. Not saying other ways of seeing things is wrong just saying more than 1 way to skin a cat for sure.

Original facts = engine temp does not rise above 140* when on the road.
Info added = Gauge agrees with secondary devise or a pyro reading, at idle temp will rise to 180/200.
Desired outcome = temp reaches 180 quickly on start up and lives on the t-stat or does not overheat.

I see this as a shop would. I want to meet desired outcome and get paid for all my work. I have no additional info other than what is stated above and was told to fix it. I perform test that is quick and isolates component. I get paid for testing time and too confirm what parts if any are needed. I think it is probably an open t-stat or even a missing t-stat but if I just replace it and am wrong I eat labor and the part costs plus still have to perform the diagnostics.

There are still other possible causes or ways to defeat the system but all will show up as coolant temp not having a hot/cold side at the t-stat.

Not to confuse this thread I started another at http://clubcobra.com/forums/showthre...threadid=96118 How many ways can you think of

You keep that under your FE patrickt??;)

I can answer this one as I had ERA188 out on Sunday as well. While running in cooler temperatures, your radiator is so efficient at moving air through it that the water/coolant temperature is not getting above 140-160 degrees until you stop forward movement of the car. This time of the year it is quite common for the car to run colder than it normally will. As the ambient air temperature rises, so will your cars normal operating temperature. I could only get my 427 Sideoiler up to about 160, but when stopped for traffic, had no problem watching the temp gauge rise to 180-190, this also let me check to see if the electric fan was kicking in automatically (which it does like clockwork). Wait for a day where the temperature is above 75 degrees (maybe a little humid to boot) and I am sure you will see your temperature gauge back to 180 degrees most of the time. Had my pyrometer with me and took shots at the radiator, upper hose, lower hose, and engine block, all within normal specs........So relax for now and enjoy the drive, nothing wrong with your car.........


Bill S.

In view of Mr. M.'s post, send the customer a diagnostic/review bill for $600 and tell him there's nothing wrong with the car. Compliment his color scheme as well. Yep, good to go....:)

Be carefull with the infered guns, if the emmissivity value is off you reading will be off by 30 degrees. I am sure the default value is 1 which is good for a flat black surface. #2 the cheaper one, less than $30K it takes an average of temps, if you are 1 foot away it is probably averaging a 8" diameter circle so put it right up on the component. They are best used to check for realitive change not absolute temp, now get an IR camera looking at thousands of points we are differtn

Or, you could take shots using your IR gun at a cup full of water and ice, and shots at a pot of boiling water on the stove, and see how close they are to 32 and 212. If you can get, say, a 150 reading from a pot of boiling water (and you're not at the top of a mountain) then it's time for a new tool. ;)

Say what????

I agree with the guy that said you have a very efficient cooling system and the moving cold air is causing your driving temp to drop so low. To prove it, do what the truckers do in cold weather and block off the radiator opening completely with cardboard.

I just returned from Skiing in Utah and while driving my Jeep at night in 20 degree weather, my temp gauge never got anywhere near normal operating temps. Later in the day when the outside temp warmed up to 70 degrees, the Jeep went back to normal temps.

You're fine. Enjoy the drive!

Dumb question. Does the radiator cool better in dry weather verus humid, if the actual temp is the same?

Not dumb; the answer is the radiator works better in a dry environment of equal temperature. The same with your skin -- you "cool off" easier in a less humid environment even if the temperature is the same.

You should be happy you have a cool running engine,and very efficient cooling system!