Final conclusion

[Ron & Dee]

After all of my posts on cooling I have come to the conclusion after reading all the replies, that what is normal for some may not be normal for me.

Watching my dash temperature gauge for four years and becoming comfortable with the positions it was showing me during various driving conditions, I felt sure that my operating temperatures were normal for my engine. No over heating problems, just right

After the coolant and thermostat change, the dash temperature gauge started reading at a different position so I decided to purchase a Scangauge to determine exactly what my engine temperatures were running.

The old position was registering 204 degrees and now the new position is registering 207 degrees.

The conclusion: I could have a wrong thermostat, I could have an obstruction, or the ratio of coolant is wrong.

The only remedy I can come up with is to start over completely with a new flush, thermostat check, and new coolant. This seems a little expensive but I’m at a loss as how to go about finding the problem?

Any suggestions?

Ron

[edgray]

RON: with all due respect, IMO, you are stressing over the wrong issue. The three degree "difference" you are seeing is no big deal. I would be more concerned about finding the cause of the why your engine is (and apparently always has been ) running more than 5 degrees above the thermostat minimum of 195.

In another thread you posted that you saw 211 degrees on the new SG II, and that the main fan did NOT come on. If that is correct, I suggest you spend your efforts (and $$) fixing that problem, rather than on replacing the new T-stat and coolant.

As reference, when under heavy load, my 03 will run up to about 204-206 on my OEMY programmed SGII and then the fan clutch pulls on the large (roaring) fan which causes the temp to drop back to ~200 almost immediately, where the fan disengages until it heats up again. This is how the system is designed to work, I believe. IF you got to 211 without fan engagement, I'd have the FCA checked-perhaps it has failed. You need that thing to work to pull in the extra cooling air when normal air flow thru the radiator is not sufficient to cool down the super-heated coolant. Good luck, ED

[ruppr]

Ron,
Just a gut reaction, but your talking about very slightly over a 1% variance from the original. Seems to be pretty close to me, just my opinion. I do know some after market products do not completely match OEM set points, for what it's worth. But I agree with Ed on the fan engagement.


Best,

Bob

[dieselclacker]

Ron, I believe you are showing too much concern over a 3 degree temperature rise after your recent thermostat and coolant change. 207 degrees is within the normal temperature range of your engine. One other possible cause for the slight rise, could be because the old coolant mixture was less than a 50/50 mix, which would make the temp gauge read a few degrees lower than it does now with the new 50/50 mixture. Were it me, I would not worry about the slight rise in temp of the coolant after the coolant and thermostat change, and I sure as heck would not change out the stat or the coolant again. Just my opinion.


Dieselclacker

[FrankO]

Are you sure you installed a 195 Thermostat? These are mechanical devices and you are reading the results of a digital measurement. There could be some variant in the two. I would be concerned that the fan is not kicking in so I would be looking at that for sure.
Frank O.

[Ron & Dee]

The big fan is working

It came on this morning during a test drive with the dash ac on, out side temperature 77 degrees. The fan came on at about 211+ degrees, I didn't see it register 212, but after the fan came on it knocked the temperature down to 202.

That means that my big fan used to come on around 208 + or -

The only way I would know what range of thermostat was installed would be to put it in hot water and see at what temperature it started to open. The people that installed the thermostat assured me it was a 195.

Thanks,

Ron

[DAN L]

Quote:

Originally Posted by Ron & Dee The big fan is working It came on this morning during a test drive with the dash ac on, out side temperature 77 degrees. The fan came on at about 211+ degrees, I didn't see it register 212, but after the fan came on it knocked the temperature down to 202. That means that my big fan used to come on around 208 + or - The only way I would know what range of thermostat was installed would be to put it in hot water and see at what temperature it started to open. The people that installed the thermostat assured me it was a 195. Thanks, Ron

the thermostat usually has the number that it opens at stamped on it. to see that it is performing correctly, you can put it in water with a candy thermometer and heat it.
the stat is supposed to be installed only one way. it has an arrow flow direction stamped on it. the stat can be installed reversed. i do not know what would happen if it was installed backwards, but suspect it would run hotter because the sensing "pill" would not get the hot water as soon.
you need to have the right kind of (silicate free) anti freeze installed in the 8.1 for the engine to perform correctly. if the wrong type of anti freeze was installed it could run hotter and can cause you all kinds of problems including water pump failure. i use AMSOIL synthetic premium anti freeze coolant mixed 50-50 with distilled water.
if the mixture is stronger than 50-50, any coolant will run hotter. you should use filtered drinking or distilled water to dilute the silicate free anti freeze per the workhorse chassis manual page 49. i cannot find my reference for how much the cooling system holds. i remember that the reference number did not include the motoraid heater system, so i mixed my coolant before i added it to the radiator. when i flushed the system, i used filtered drinking water.