Which t-stat to use.

[gregbr]

I have a 160 deg t-stat in both my trucks, with the idea of keeping it as cool as possible to prevent boilover or running it hot. I can't stand seeing the temp at 200 deg on the gauge (nuts maybe). What's best & why?? Greg

[Longhorn Man]

There are a lot of variables...
The condensation that builds up in the engine from the humidity in the air will burn off much slower with the 160 degree stat, however, most engine dyno sheets I've seen make more power at lower eng. temps. (which is why the hyper chips recomend the 160 stat) Lower engine temps can let you run cheaper fuel...lower grade of fuel anyways. The hotter the engine, the more likely it is to have preignition issues.

I say try it and see what you observe. In my case, I hardly ever take trips long enough to bring the engine to 200+, so the benifit of burning off the water was a moot point, so i ran the lower t-stat in the summer. The 20 degree differance was enough in the winter though, that my heater didn't work for squat.

[cableguy0]

the engines are designed to run at around 200. newer engines are going as far as 215 and 220. the reason for the hypertechs wanting you to run cooler is because they put severe timing curves in and cylinder temps need to stay down otherwise it would detonate. but on a normal engine you should use a 195 t stat. if you need a 160 for whatever reason something else in the cooling system is lacking.

[acloco]

....and the ECM barely gets into closed loop...so ALWAYS running on the rich side of the engine management block.

Keep your t-stats in the 195 range. If you are having problems keeping the engine cool, then you have other problems in your cooling system.

First item I would recommend - removing the inefficient engine driven fan and replace with a thermostat controlled single or dual electric fan.

Second - replace your radiator with a new, aftermarket, aluminum, high efficiency.

Third - use distilled water in your cooling system.

Fourth - use a water wetting agent - you might be surprised.

5th - aftermarket aluminum or steel higher efficiency water pump.

[Boog]

Greg. If you are referring to your 67 and 70 trucks with carbs then the ECM and closed loop do not apply.
Some will run the cooler 165 in the hot summer months and 195 in the winter months for better cab heat. I have done this also. As far as best temp stat for your trucks? It's which one the engine runs best at and which temp you feel comfortable with. Cooler intake temp makes more power. You may not actually feel any difference though. Normally I would say stay with the factory suggested temp stat. It's supposed to be just fine at that temp. If overheating occurs then the cooling system may need some attention.

[70c10]

Speaking of temps, my truck overheated today and went past 265°!!!!. My fan belt flew off today over revving the engine I think. I got lucky and limped home.

[gregbr]

No ECM's on my trucks.

I have NO problems with overheating or anything, I just don't like it being at the boiling point when all is operating perfectly. This gives litte room for a temp increase (without damage) when something is not working at 100% effeciency, like that ever happens..... Besides, how often do you REALLY look at that gauge, you could ride for awhile before you noticed it is off the scale HOT. And the 160 deg t-stat makes the entire engine compartment cooler, that's got to help everything last longer. Greg

[cableguy0]

if something bad happens its going to overheat just as fast from 160 as it is from 195 maybe a few seconds difference but not much more than that. water boils at a much higher temp when under pressure like it is in a cooling system

[acloco]

Originally Posted by gregbr

No ECM's on my trucks.

I have NO problems with overheating or anything, I just don't like it being at the boiling point when all is operating perfectly. This gives litte room for a temp increase (without damage) when something is not working at 100% effeciency, like that ever happens..... Besides, how often do you REALLY look at that gauge, you could ride for awhile before you noticed it is off the scale HOT. And the 160 deg t-stat makes the entire engine compartment cooler, that's got to help everything last longer. Greg

I hear ya. But, your cooling system is under pressure...correct? Coolant/water under pressure does not boil until the 235+ range...you get, almost, 2 degrees for every pound of cap pressure in a cooling system.

Try it....readjust your carb...and watch your gas mileage increase.

[4x4Poet]

I've switched to using Robert Shaw high flow thermostats, exclusively. I think RS' claim that their stats more accurately and reliably open at the stats' rated temps holds water(). Flowkooler.com sells RS stats. Jegs sells them as rebadged Mr. Gasket:

http://www.jegs.com/cgi-bin/ncommerc...03&prmenbr=361

[gregbr]

Yes, I understand the pressurized closed system and the extra few deg that gets you. There are good & valid points here, but the 160 does SOUND good. I'm always open to a better way, and will take all this and experiment some. I like the sound of the RS high flow t-stat, I've seen lots of problems with the standard ones. I'll try the high flow t-stats soon. Was the 180 deg factory? Thanks everyone, Greg

[cableguy0]

facotry should be a 195

[bigarmzz]

what does using "distilled water" in your cooling system do?...i dont see how in the world that would make a difference.....???

thats a new one on me

[cableguy0]

its a purer water so it wont boil as quickly. distilled water will not boil until a foreign material is introduced into it

[454HO]

distilled water = no minerals like calcium, lime, heavy metals, etc. (all the stuff that can clog up the passages in your radiator over time).

Also, 100% pure water is a more efficient coolant than a 50/50 mixture of antifreeze and water. However, running just water is asking for corrosion problems, even if it is distilled. I use RMI-25 in my cooling systems. In the summer, I do not use any antifreeze at all. In the winter I add just enough to protect from freezing, which isn't much here in Houston.

As for the thermostat, I like to use a 180° high flow stat. But then I also drill a couple 1/16" holes to help purge air out of the system when filling it up.

[acloco]

454HO...you should use some antifreeze year round....makes the boiling point higher as well.

[69 longhorn]

The old rodders theory (that I grew up on), was to try to keep that carburated engine in the 180-185 range on temp. if you keep the underhood temps a little cooler, the carb will also be a tad cooler & that does help performance. I think 160 is too cold on the temp, but 175-185 is ok in the summer heat. With that said,I doubt that you will get that sb to run @ 160, by swapping the stat tho! You will find that you may drop a little on the temp, but will notice that it takes longer to warm up. I do run a 160 stat (highflow) in my 383, & she runs tween 170 & 185 (off/on for the controls on the elect fans). The new "fuelie" stuff is a different animal, they can run higher engine temps,(and need to for the emissions controls, sensors,ect)without the fuel perculation problems that the old carburated engines had. Also, the computer will retard the timing if they try to detinate.....a totally different game , with different rules L