Thermostat questions

[SS_bnoon_SS]

With the 160 stat, my engine only runs 10-12 degrees less than it did with the stock stat, although there is a 35* difference in their rating.

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That's because changing to a lower stat has nothing to do with overall cooling system efficiency. You need to change fan turn on temps to a lower setting in programming ('03-'04). If that's still not enough, you would need either larger CFM fans or a larger radiator in order to run nearer the stat opening temp.

 

Or it could just be you got a stat that's out of spec. I've purchased a 160 that didn't open until 175 degrees = factory defect, proven on a stove top with boiling water and a food thermometer. Took it back and got another one that opened at 163 = acceptable.

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'03 or '04, doesn't matter, we don't have electric fans, nor is their ANY kind of setting in the PCM for them. Talk to me about '05, then you're talking, but that's not me. I have an '03 (Although I have added electric fans and they are controlled by the PCM - but that didn't change anything - they are set to turn on at 150, if you want to know - means they run always). I never considered a t-stat having anything to do with efficiency - that I would more relate to coolant type, pump rating, radiator type/size, fan, but not the t-stat. All it does is open up earlier, nothing more.

 

If my 160 stat is out of spec, then so is the stock one. Your truck will run hotter than 195, which is the stock temp. My motor actually runs exactly at 187, almost always. And, just because I'm reading that, doesn't necessarily mean my t-stat is operating out of spec. It all depends on where the temp is taken, but the t-stat could still be opening when it's supposed to, although I haven't checked on my stove. The dash gauge gets it's sampling from the driver's side head.

 

The big thing is using the gauge, it's not accurate. Close, but not accurate. I read mine from logging ECT, not reading my gauge.

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Oops, one thing that got left out of my post is the part where I typed '03-'04 should have read "03-'04 doesn't matter because of the clutch fan". Not sure when I deleted that as I cut and pasted some thoughts to get them back in order as I was rambling to myself... as I said, oops.

 

It doesn't change the fact that your fans running all of the time proves the point, the 165 stat is useless in the SS application without going to higher CFM fans, a larger radiator, or otherwise improving the effective cooling of the system. Having a stat that opens sooner does absolutely nothing for performance if the effective result doesn't lower overall operating temp. The stock stat can run at or below it's rated temp depending on the rest of the cooling system, but that would create hots spots as the stat would be running partially open, restricting flow.

 

You're right in that your stat may not be out of spec, but it easily could be and is so easy to check prior to installation. Even with a 4 core all aluminum radiator and 2000 CFM fans you probably couldn't cool a half open stat on a hot day. Checking on a stove top is one easy way to check this mass produced part, they do screw up from time to time. With the '03 stat costing so much, someone could do well to check up on the quality control before going through the installation trouble, that's all I'm saying here.

[TBSS]

most all 160 thermostats in a gen III small block run at 172-174º. this is the temperature i shoot for either way. with the exception of the possibility of setting codes P0125 and P0128, there is no reason not to run a cooler thermostat. (unless of course your average outside temperature is below 30º). there is no reason to consistantly run the engine at 195º and above.

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So gas mileage doesn't suffer/decrease with a cooler motor?

[zippy]

most all 160 thermostats in a gen III small block run at 172-174º. this is the temperature i shoot for either way. with the exception of the possibility of setting codes P0125 and P0128, there is no reason not to run a cooler thermostat. (unless of course your average outside temperature is below 30º). there is no reason to consistantly run the engine at 195º and above.

So gas mileage doesn't suffer/decrease with a cooler motor?

 

 

i have never experienced a loss in milage after a thermostat swap. ever car i've owned i've put a 160 right after i bought it. my last camaro was able to knock down 30mpg on the highway with the stock programming and 160 stat. i'd have to go with no for the answer to that. i've never seen that to be the case.

[BenKey]

It doesn't change the fact that your fans running all of the time proves the point, the 165 stat is useless in the SS application without going to higher CFM fans, a larger radiator, or otherwise improving the effective cooling of the system. Having a stat that opens sooner does absolutely nothing for performance if the effective result doesn't lower overall operating temp. The stock stat can run at or below it's rated temp depending on the rest of the cooling system, but that would create hots spots as the stat would be running partially open, restricting flow.

 

You're right in that your stat may not be out of spec, but it easily could be and is so easy to check prior to installation. Even with a 4 core all aluminum radiator and 2000 CFM fans you probably couldn't cool a half open stat on a hot day. Checking on a stove top is one easy way to check this mass produced part, they do screw up from time to time. With the '03 stat costing so much, someone could do well to check up on the quality control before going through the installation trouble, that's all I'm saying here.

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Did you notice in my last post where I said that I set the fans to 150*?? Since there is no way that the engine would run below that - that means that I set them to stay on and they stay on. I thought that it would be easy to figure that out. So the fact that I set them that way proves what point??

 

My fans run at half speed all the time. Since at full speed they pull 5500 cfm, I would guess that they are at least 2000+ at the speed I have them set all the time. Other times they come on at 100%. My harness is a little different than a factory harness - gives me better control and selection of my fans.

 

I never installed a t-stat for better performance. It's easy, I put it in to run lower temps. Since the stock motor, which I also don't have, runs closer or over 200*, if mine (Stroker 410) runs at 187* in the middle of summer in FL, then it has done what I wanted it to.

 

Have you ever logged temps with the SS?? If so, with what? Believe you're operating at the stock t-stat setting. Believe your gauge on your dash? My gauge reads 170-175*, what I've given you is the actual ECT (187).

 

I know that a stat can be checked on the stove. I did it a few trucks ago. I choose not to. I gaurantee you that the factory t-stat is more mass produced then the one I have. Maybe everyone should pull theirs to check them?

[AWDGM]

Here's an interesting site that shows how temp affects performance and engine wear. http://performanceunlimited.com/illustrati...hermostats.html

 

BTW..I looked at a few stock thermostat that I took out of 00, 02 and 04 trucks and they are all marked 100C. That is 212 degrees F!!!

I had a guy from my forum tell me his 04 was marked 96/100C, so I take it that is the range it opens. What are your stock thermostats marked and what do they actually open at?

 

I was replacing stock with a 180 yesterday in my 99 so I did the stovetop test. I always test the thermostats before I put them in. Of the 4 stock thermostats, one opened at 205 two others a hair over 212 degrees (the water was boiling) and one still wasn't open at 220, the one from the 99. No wonder it was running hot. It must have been running on strictly bypass. The bypass is the second valve hanging down off the thermostat. The 180 opened at 190 BTW. Close enough for a work truck!

 

Butch

[SS_bnoon_SS]

Did you notice in my last post where I said that I set the fans to 150*??  Since there is no way that the engine would run below that - that means that I set them to stay on and they stay on.  I thought that it would be easy to figure that out.  So the fact that I set them that way proves what point??

 

Yes, I most certainly did read your last post about turning on your fans at 150. Since the fans run constantly, your killing them waaaaaaay faster than you need to because the rest of the cooling system is to small. Fans should be able to rest once in a while, even at full operating temperature. When I turn the fans on at 180 degrees, I expect them to turn off at 172 degrees. If you're running at 187 degrees, and that's where you want them, that's fine, but not the point when running a 160 stat in most cases. A 160 stat can be run at 165-170 degrees if you want it to, doesn't matter which vehicle it's in, doesn't matter who's doing the programming, so long as the cooling system is up to the task. Running fans full time from 150 degrees and the truck still runs at 187 logged temps... Why not run them at 180 or so since they never reach a turn off temp?

 

 

Have you ever logged temps with the SS??  If so, with what?  Believe you're operating at the stock t-stat setting.  Believe your gauge on your dash?  My gauge reads 170-175*, what I've given you is the actual ECT (187).

 

That has what to do with anything? Actual coolant temp depends on where the sensors/sending units are located within the system. I haven't programmed anything yet on the SSS, but I have over 5 years with programming OBD-I and OBD-II Fords, 3+ years programming pre-OBD ECU's for my '86 Trans Am with a 383, and do know how it's done. The TA fan on temp is 175, fan off temp at 170 and it runs right there on 100+ degree days with the AC on on bumper to bumper traffic. The 2000 Mustang GT the wife drives has it's fan on at 180, fan off at 172 and it does the same thing in traffic. My '99 Contour with a 3liter swap ran 170 fans on, 163 fans off, all day in traffic for summer, then would switch to 190 fans on 180 fans off for winter. The point of that part of my post means that most factory cooling systems do not contain enough overhead to actually run a 160 stat to full benefit.

 

I know that a stat can be checked on the stove.  I did it a few trucks ago.  I choose not to.  I gaurantee you that the factory t-stat is more mass produced then the one I have.  Maybe everyone should pull theirs to check them?

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Uhhhhhhh, yeah, nice argument... Since you got one that works right, that means everyone will? uhhh huh... Just check the aftermarket ones before you put them in people. It's so easy to do, takes very little time, and can save you headaches down the road. What happens if you would happen to get a stat out of spec, or worse yet one that's been packaged wrong? It happens often enough that people still hear about it from time to time.

[zippy]

i've never seen a gen III engine run 160º with a 160 thermostat in it.

[SS_bnoon_SS]

i've never seen a gen III engine run 160º with a 160 thermostat in it.

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But it could run lower than 187 with fans on at 150...

[BenKey]

i've never seen a gen III engine run 160º with a 160 thermostat in it.

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But it could run lower than 187 with fans on at 150...

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I seemed to have lost the whole point of what you're trying to say. Please don't do a re-attempt.

 

If my fans came on at 100%, I could get my temps down around 170-175. Being an electronics tech, it is my experience that things break more often when cycling them - it's a known fact even. So, I run my fans at 50% all the time and running them at 100% all the time is just not feasible - to me. I can nearly gaurantee that keeping it that way will ensure the longevity of the fans vs them cycling on and off. If I go to the track or something, maybe I'll run them at 100% in between runs.

 

On the street, this is the way I choose to do it and when it comes down to it - that's all that matters.

[SS_bnoon_SS]

I seemed to have lost the whole point of what you're trying to say.  Please don't do a re-attempt. 

 

 

Ohhhhh, but I feel I must...

 

With the 160 stat, my engine only runs 10-12 degrees less than it did with the stock stat, although there is a 35* difference in their rating.

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This is the part that I didn't care for. To me, saying a 10-12 degree difference is all that you see with a 35 degree difference in their rating would mean something totally different if it happened running full voltage to the fans... You stated why it doesn't run closer to 160 because you choose to run only 50% of voltage to the fans. I stated several reasons why your truck *could* run closer to the rated temp of the stat, that is all. Nothing is holding you to 10-12 degrees below stock temps except yourself...

 

BTW, I totally disagree with running lower than rated voltage to capacitor discharge start fans. Most fans I've worked with have a 10-16 volt operating range. Lower voltages can cause arching/scoring, even on brushless fans. I choose to cycle the fans on an off with a min/max duty cycle length.

 

On the street, this is the way I choose to do it and when it comes down to it - that's all that matters.

 

 

Difference of opinion. It's all good.