Thermostat testing and engine temps

[madmaxx]

I noticed going down the freeway my coolnat temp reading was in my opinion low. I pulled the thermostat and found it to be 180F, the preferable temp. I put in a pan of water and noticed at 180F it opened. The interesting find though was even at 160F on the way down it was still open to some extent. I purchased a 180F and 195F Mr. Gasket balanced thermostats. I did the same test and got the same results. The opened at the correct temps yet did not close until 20F cooler than there set point. Since the SPF cooling system is so efficient it is very possilbe you can be going down the freeway and maintain a coolant temp less than 165F which as most know is very deterimental to engine life. Anything less than 180F an you experience accelerated cylinder wall wear. To futher test I drove on the freeway for 30 minutes and a constant speed to eliminate the possibility that it just takes longer for the thermostat to reduce it opening and maintain its temp.

Anyone know of a thermostat that closes near its opening temp in order to maintain the preferred coolant temp of 180F at all times?

[elmariachi]

The $6 NAPA t-stat in my FE opens rated temp and starts to close right at the rated temp.

[madmaxx]

wow, may need to check that out. I was also wondering does you car have a bypass on the thermostat housing to water pump? I wonder if mine is too large and even at highway speeds if the thermostat closed the bypass provides to much circulation.

[elmariachi]

I am running the bypass hose, and I have 4 small 1/8" holes drilled in my t-stat. After sorting out that my early heating problems were due to not enough fan and shroud, I am now enjoying a very cool running and predictable FE. Down the road when its 70*F outside like today, temp gauge is at 80*C. When I stop, the temp crawls up to 85*C, but no more. Back when it was 90*F outside, it would run 85*C down the road and maybe 90*C at idle, but no more. If I were to install the same t-stat without the holes I could probably see the opening/closing on the gauge.

[*13*]

If you keep the water temp at 160 for a few minutes does it close? If the engine is constantly producing heat you want the thermostat to allow enough flow to keep the coolant at an optimum temp. The thermostat may need to be open "a little" to do that. Where do you have your temp unit mounted? What reading are you getting running down the freeway?

[madmaxx]

Around town (20-45 mph) I stay at about 80c (170F) still below my 195F thermostat, if I sit at lights for 10 minutes it will creep to 100c and the fans kick on and kick off at 97C. If I cruise down the freeway at 65 mph in 5th gear my smith temp gauge reads 65C with the 195 mr gasket balanced thermostat. In all honesty the difference between the 180F thermostat and 195F thermostat is negligible. The temp sending unit is in the manifold on the drive side of the thermostat housing the fan switch is in the radiator and designed to come on at 197F and off at 188F. It makes sense that I see 100 on my temp gauge when the fans kick on since it is engine coolant temp while the fans are radiator coolant temp. This gives me the impression the gauge is reading correct. maybe not.

[*13*]

Do you know anyone with a temp gun that can read your engine temp? ...so that you don't need to change parts out to test that they are operating correctly?


something like this?
http://www.ohiopowertool.com/p-2178-...y-2277-21.aspx

[209]

Hello all,
I'm really surprised at all the new stuck thermostats that we go though. Mine(185) was stuck from new and I had one heck of a time getting the temp to 180+ before a change to a new unit. I was putting, heaven forbid, cardboard in front of the rad to bring the temps up. Now it's great but other problems now exist. 209

[madmaxx]

I agree. I may pull the temp sending unit out, get a pan of boiling water and monitor the water in the pan temp and gauge reading as the water cools. The only problem with temp guns is if the emissivity value is not set correctly you reading can be off 30F.

Originally Posted by *13*

Do you know anyone with a temp gun that can read your engine temp? ...so that you don't need to change parts out to test that they are operating correctly?


something like this?
http://www.ohiopowertool.com/p-2178-...y-2277-21.aspx

[madmaxx]

I pulled the temp sending unit and checked it with a calibrated thermometer it is dead on from 100C to 70C/155F. Going down the freeway tonight I got the temp down to 70C!!! or 155F. Thermostat is for all practical purposes useless. By the way it is a new 195F!!! Optimuim engine longevity would be from 85C to 100C.

I guess I play the same trick as I did with the oil cooler and install a piece of plexiglass on the bottom 1/3 of the radiator. I have no idea where all the circulation is comming from the thermostat has to be closed at 155F. Is is possilbe the water pump bypass is causing the circulation??

Coincedentally someone on the FE forumn has the same issue, we are all wearing our engines out prematurely. Next cobra I will do the engine and trans installs since I have to figure out all the solutions anyways LOL!!!

[*13*]

You can always buy an inline housing to get the stat away from the block. I bought mine from Wilson Manifolds. Mine was more or less out of necessity since I have no place in the manifold for one.

[madmaxx]

Ultra cool, I never even thought about that, I guess that would completley isolate the radiator since it is away from the water pump etc. Thanks!!!!!!!

Originally Posted by *13*

You can always buy an inline housing to get the stat away from the block. I bought mine from Wilson Manifolds. Mine was more or less out of necessity since I have no place in the manifold for one.

[Bobcat]

In my mind , the probable reason you aren`t getting up to temp. is that our radiators etc are all sized to handle max hp in a hot environment ... i.e , temps in the upper 90`s ... at least in SC , and you are not putting out any where near max hp and therefore heat when cruising ... and your ambient is a lot lower now . I`m also having the same problem now that it has cooled off here ( upper 60`s to low 70`s ) . I also have an aluminum engine , so its heat rejection/cooling ability is pretty high . Sounds like you have more heat rejection ability now than you have heat/BTU`s .
My solution is the same as yours ... block off part of the radiator . I also thought I had a thermostat problem , but really think that it is what I said above .

Bob

[madmaxx]

I agree with everything you say. I just hate to put a piece of plastic, carboard in front of radiator on a $60K plus car. Guess I should have bought a cheaper car LOL!!! I live in Houston and tonight it was 70F, I could not imagine if it were 40F outside.

Originally Posted by Bobcat

In my mind , the probable reason you aren`t getting up to temp. is that our radiators etc are all sized to handle max hp in a hot environment ... i.e , temps in the upper 90`s ... at least in SC , and you are not putting out any where near max hp and therefore heat when cruising ... and your ambient is a lot lower now . I`m also having the same problem now that it has cooled off here ( upper 60`s to low 70`s ) . I also have an aluminum engine , so its heat rejection/cooling ability is pretty high . Sounds like you have more heat rejection ability now than you have heat/BTU`s .
My solution is the same as yours ... block off part of the radiator . I also thought I had a thermostat problem , but really think that it is what I said above .

Bob

[wrench87]

are you running under drive pulleys or a edelbrock waterpump? my cobra does the same thing i am using a mr gasket t stat, edelbrock waterpump and unerdrive pulleys and a ron davis radiator.

[madmaxx]

yes mr gasket, weiland water pump, no underdrive pulleys. I just cannot figure out how the heck I am getting circulation to the radiator in a volume sufficient to get the temp down to 155F. When looking at a thermosat the bulb end, or end with the temp stamp goes towards the engine or into the manifold correct?

The radiator feeds the bottom of the water pump, water circulates through the block, the heads and out the intake manifold where if the thermostat is closed the only way around is the bypass hose. So water goes in the bypass hose to the suction side of the pump and back through the engine, it never goes through the radiator. The only head transfer is in the water pump, besides conduction how else is the radiator even in the game when the thermostat is closed?

[madmaxx]

The heater cant be part of it since at a light or letting it sit in the driveway it will hit 100C and the fans will kick on and cool it down. Wow I have a mystery on my hands.

[madmaxx]

One thing that is definetly not helping is my Mr.Gasket Balanced thermostat POS passes alot of water when FULLY CLOSED!!!! I guess they designed it that way to bleed air. I guess I will go back to a cheapo 195 where it does not pass so much when closed. Another thing when I installed the mr.gasket i had to use two gaskets since the flange was so thick. the saga continues!!

[madmaxx]

Solved, Fixed, complete. Going down freeway tonight temp stuck at 180/82C around town stuck 185/85C. Problem was the stupid fuking Mr.Gasekt balanced piece of sheet thermostat. The fuking thing never seals off even when closed!!! Go pick one up and blow through it, it is alway open!!!!!!!!!!!!!

OK simple solution Duralast 195F thermostat part number 15359 at Autozone $6.99. It even has a small hole for air bleading. However it has a little brass plug that gets pushed closed when all the air is purged.

I have never seen the car warm up so quick. It was beautiful. Nothing over radiator and bypass hooked up. My testing in hot water on stove showed it opened at 195F and closed at 188F. Thermostats open at the design temp but close about 10F lower, this was consistent will all my testing.

[*13*]

Sweet! Nice work! It was Interesting to follow through to conclusion.