• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

What t-stat cooling upgrade is the best?

So dont listen to an argument that it doesnt spend enough time in the radiator.
Click to expand...

Made my living as an Electrical Engineer, so I will readily admit that my understanding of thermodynamics, while being better than rudimentary, is still a just a bit beyond the basics. It was one of the very few courses that I actually hated...
That being said: Even as an old retired guy I guess I'm still a student and would really appreciate it if you would share your knowledge with the rest of us. I truely realize what a complicated system this is and would like to get my truck operating as well as I can so that it will run forever :rolleyes5:

-- Well, For as long as possible :smile5:. Since HEAT KILLS - Controlling the engine's heat is, no doubt, one of THE keys to it's longevity.

I guess where I'm getting lost is because my bucket truck is pretty heavy all of the time, even if I'm not towing something. It was showing a tendency to get pretty hot on long grades a while back, but just cleaning the radiator solved that problem. I'd guess that after 13+ years that the water pump impeller is probably getting near the end of its service life and that it should be changed - But to what?

The stock system *seemed* adequate for quite a while, but if I'm going to go to the trouble of replacing the water pump I'd like to do it right and not just make wild guesses based on my inferior understanding of the dynamics of the cooling system.

Now I realize that this will be fairly difficult without going into the math, but to be honest the complexity of those equations just makes my head hurt, so in layman's terms if you would. I mean just basically explain how much heat can be transferred given the tubing size and efficiency of the radiator etc. etc. in these trucks and how much flow that system needs to optimize the heat transfer at the engine's max designed operating temperature.

Please sir, just the end results and not all of that confusing math that you've had to slog through to come to your conclusion.
Thanks in advance Buddy!

Looking forward to being enlightened!! As Lew Wallace said: "Knowledge is power." Or as Don Aarant said: "Nitrous oxide is power" :)
 
Last edited by a moderator:
I can't say which which system is better the twin t-stats or Heaths new single t-stat Hummer water pump but I can definetly say that my truck has had heating problems since new, part of the problem was solved by installing a free flowing exhaust and a very thick 2 core aluminum rad. The truck would still go up to 215f on big climbs even in cool weather.

I switched to the dual t-stats and HO pump no other changes like fan or fan clutch, (no ones kit I bought the parts seperately). Since doing that I have had no heating issues the temp. stays on 195f. The max I have tested the system is 95f temps pulling 7% grades with camper on and climbing at 35mph and I typically don't let the pyro go over 1000f pre turbo on big climbs at about 8psito 10psi boost and 2300 to 2400rpm. I have yet tested the system in the worst case synerio like some Southern's might find like 110f and wide open throttle climbing at 25mph pulling a big load.

I suspect the twin t-stat system will be much more negatively effected by an internally corroded rad. perhaps with a new clean rad, the sytem works as designed with the proper balanced amount of water circulating through the rad and the block but after a few years or poor water or old coolant the rads. core become corroded and slow's the flow through the rad. This may account for why Heath single t-stat system (more positive flow system) would work more consistently on a greater variety of trucks with new or older more restrictive rad's. My guess is in a perfect balanced situation with everything new (rad,t-stats so on) GM's twin t-stat is in the short term any way is the better system but in the long term (real world) the heath system may provide a better alternative. Just a thought.
 
Well, its all actually explained very thoroughly in MaxxTorque, the specific part being in Spring 2008 edition. That magazine is the best I've seen for diesel trucks.

The simplistic way to explain the equations is that flow is in them, and increasing flow increases heat transfer.

If you think the water is going faster so it doesnt cool as much you might be surprised to think it might see just as much radiator time and more since its going to be back sooner. And the efficiency of the heat transfer doesnt increase with time very much, so the water in the block might get heat soaked and the faster you get it out of the block then more water behind it can pull more heat off.

Air temp is the limited factor since water cant shed more heat than air can take, and the delta in temperature between the air and the fluid will increase the amount of heat shedded. That is why it is more advantageous to cool your oil with additional air coolers and additional capacity. Oil gets hotter than water and cools the engine when it runs through it, so air can more efficiently cool the oil, so after the normal water upgrades, it makes the most sense to spend the extra dollars on good oil cooling, like frame rail coolers or adding more cooler in the bumper. Cooling the oil will cool your water too, since the air that does go through the radiator wont get heated more by the oil, larger delta between the air and water.

As the delta in temperature approaches zero the heat transfer efficiency approaches zero, which is part of the reason that the most cooling is done the instant the water hits the radiator and as it goes through the heat transfer efficiency decreases as the water gets cooler.
 
Thanks Buddy! Your fairly simplified explaination was just what I was looking for. Made sense of a complex problem.
Well done :thumbsup:
 
So for decent towing, say 14K, what is going to be the best for cooling system performance? dual or single t-stat? I am pretty sure that a 130 HO water pump will be the best choice.

I do think that when i replace my oil cooler lines, i might as well go with the DSG kit, which comes with the bigger oil cooler.

And as a response to Buddys question about me not wanting to buy SS diesel, lets just say, im gonna try and reduce FSD research funding! :D
 
GM decided two thermostats helped, and they must have had a reason.

SSDS sells it all as one kit, with a more cost effective fan/clutch upgrade, so its convenient. But you could just get the parts from anywhere, dont need a kit, just the parts from a 97, except the upgraded DMAX fans of course.
 
You mean the same GM that had a reason to put a OP amp on the side of the injection pump, yeah they always get it right, dual stat isn't all GM thought it should be either, I have some thoughts rather lengthy actually started on them yesterday but doing holiday stuff I had to log off, (more to come later) FWIW my new engine build has single stat, and a new 6.2 h/o pump with spin on clutch, I have same pump/fan/clutch on my burb now, but that still has dual stats, for now, I don't tow with it just a people mover so far so good with that set up.
 
TD,
If I was to put a bypass restricter on my burb, wouldn't that give me the best of both worlds? dual t-stats w/bypass restrictor and HO waterpump? All with a clean rad of course.
 
For those of you that have the 97 and up, you can go to your dealer and get the D-Max fan for about 40 bones and it will bolt in place. IIRC, Bill also said something to the effect that a water wetter will also help with the transfer of heat and reduce 'hot spots' in the block/heads. Now it would seem to me that it would also work to transfer the heat to the radiator tubes more efficiently and be dispersed quicker.

I could be wrong...its happened before. "I thought I was wrong once, but I was mistaken."
 
For the most part, I think water wetter increases the boiling point of the water to let it stay fluid better through the block, so it doesnt turn to vapor. And that helps a good amount.
 
buddy said:
For the most part, I think water wetter increases the boiling point of the water to let it stay fluid better through the block, so it doesnt turn to vapor. And that helps a good amount.
Click to expand...


Good thought. Not quite right, but still good.

Water-wetter is a surfactant - what it does is decrease the tendancy of water to form its' own surface, which lets the water stay in closer contact with the metal surfaces of the engine and rad.

Without a surfactant, the water will 'unstick' from the metal surface and the resulting air pocket will superheat at that point (cavitation boiling, steam formation). This disrupts the smooth flow of water through the system, gives you 'hot spots' in the block, and can create a runaway condition leading to airlock. (worst case)

The water-wetter prevents this, and lets water act to absorb, move, and release heat (a heat-sink, if you will). Surfactants also keep bubbles from forming in the liquid, something that helps to prevent vapour formation, as Buddy indicated above. This helps, in a pressurized system, to keep the internal vapour pressure of the water from exceeding the cohesion of the fluid, helping to prevent boiling.

I use 2 bottles of Redline with a 50-50 mix of antifreeze and distilled water.

Now: about boiling point... mixing the water with good quality antifreeze will change the heat absorption characteristics of water, and will help to increase the boiling point in a pressurized system.
 
You must log in or register to reply here.
Back
Top