Dual Thermostats on a 6.2?

[uglytruk]

I just put in almost new 4 tube rad in my Blazer, and going up a steep hill, 30 mph, with a 7 1/2 Fisher plow, the engine still overheated.

Otherwise it runs dead on 200. When I stopped at the top of the hill, the fan stopped turning immediately as I turned the engine off. I immediately re-started it, to circulate coolant. Just wanted to check the fan operation.

Can I put on the dual Tstat that my '94 6.5 has?

Any other suggestions? Maybe a deeper blade fan?

Here's the vid...

You can forward to minute 1:40 to avoid some of my banter...

http://www.youtube.com/watch?v=bwZR9U1LPBM

 

[Mikey von]

I am torn over this issue as well for my build. I have both the single and dual stat setup ready to go. I will be running the HO water pump. I know that Heath at Heath Diesel feels that the single stat is the way to go. There most be something to dual stats though, as they run dual stats on the re-engineered P-400 (the latest and greatest 6.5L).

In my researching, I do think there are some issues getting dual stats to fit on a 6.2L block. They surround getting the high ideal/cold advance solenoid to fit properly. I think there is also some adaptation of the cruise control.

 

[uglytruk]

Could I have a 6.2 outlet welded to have a 2nd tstat?

 

[diesel4me]

I know nothing about dual thermostats,but all of my GMC plow trucks would overheat with my Fisher blade on them if I went more than 6 miles with them,like clockwork the temp gauge pegged,then they would peuke over!..I tried numerous remedies like new thermostats ,flushing the radiators,angling the plow blade,etc..nothing helped..

One day while I was delivering parts to a local Chevy dealership,I asked the parts counter guy about my overheating dilema,who was reputed to be very well versed in all things GM..he said "Oh,we always "lock" the fan clutch on the trucks we install plow packages on here...you just take the little coil spring on the fan clutch out of its holder,rotate it 180 degrees,and clip it back in the holder,and then the fan clutch stays locked up all the time...I did that,and it never went over 1/4 of the way past the cold mark on the temp gauge again--the fan sounded like a jet plane taking off and it did rob some HP and mileage,but it was better than having it boil over in 7 miles!..

 

[85-m1028]

peninsular diesel sells a high flow water pump in a clockwise rotation so you use it on a v-belt apllication.

gotta get coolant flowing or dual thermostats are pointless.

 

[kennyw]

In this situation, I believe lack of air flow is the bigger problem than lack of coolant flow.

 

[85-m1028]

In this situation, I believe lack of air flow is the bigger problem than lack of coolant flow.

my bad, more flow?? for dual thermostats?? what was I thinking??

 

[Wrench]

my bad, more flow?? for dual thermostats?? what was I thinking??

Kenny's right. Dual t-stats, while a sexy fix, is not going to help the OP with his overheating problem. I've run a dozen 6.2/6.5 trucks in a MULTITUDE of situations, including towing 14K pounds in 90 degree weather behind my K30 crew cab dually. When you work the engine hard, you need more coolant flow.

However, a Blazer going up a hill at 30MPH is not going to overwork a 6.2, even with that great heavy plow up front . His issue is lack of air flow through the radiator, and the fix will be a better fan and/or a locked clutch. Electric 'helper' fans pushing air from the front would help too.

Talking dual t-stats and high flow water pumps is fun and all, but it won't fix the problem.

Uglytruk, is that still the original fan? or have you swapped for a J-code fan yet? makes a world of difference . . . .

 

[85-m1028]

a proper cooling upgrade would involve a larger radiator "than factory" newer style four row will have 25% larger cross tubes.

factory water pump is about 60gpm. Later upgrades include 130gpm factory pump reverse rotation or counter clockwise for a serpentine application. 110gpm available in v-belt application

stanton makes a thermostat that opens at 180 and flows a little better but I personaly never tried one.

Fatory upgrade dual themo crossover, outlet is right in the area where the throttle linkage attaches to injector pump.
"modification needed" involves cutting and rewelding outlet at less of an angle.

Factory 5 blade fan leaves much to be desired! the odd spacing of the blades can cause a nasty vibration if locked up. the later factory upgrade was a six blade reverse rotation and pulled a little better.
http://www.oliverdiesel.com/products/haydenfanclutch.htm

I have seen some old hmmwv plastic 10 blade fans that were clockwise v-belt that I thought would be a good upgrade. couple that to a heavy duty fan clutch
http://www.stock-number.com/06Class9HUMMWVCooling.htm

The best upgrade for fans has to be the modified duramax fan with heavy duty clutch. but this is for a revese rotation sepentine application only.

http://motors.shop.ebay.com/i.html?...ccessories&_odkw=diesel+6.5+duramax&_osacat=0

That's just the cooling system!
So there are options out there just depends on what you're looking to do.

 

[Wrench]

This is all very true, but when you have a fairly stock engine overheating in fairly normal everyday running, you want to figure out why before you start throwing money at it.

Any one of us could take a boatload of money, get the latest and greatest in 6.5 cooling systems, and be sure that it's never going to overheat again--but that's not always practical. Flowing more coolant through the system doesn't change a thing if the coolant isn't getting cooled, and there is NO evidence that his truck is generating a lot more heat energy than any other stock 6.2 that never overheats at all. OTOH, there IS evidence that air flow through his rad is likely a lot less than normal.

My pulling truck in it's latest incarnation has a serp. kit with a late model 130 GPM water pump, dual t-stat crossover modified to work with the 4911 pump, 9-blade 21" Duramax fan with late model HD clutch, all with the stock J-CODE radiator. The dual t-stats are there to keep the heads from cracking. The only upgrade that made a noticeable difference when I towed heavy was the Duramax fan. Every upgrade went on by itself, except the water pump and dual t-stats, which complement each other.

 

[85-m1028]

forgive me pls!!

I forgot it's a plow truck that most people would rather fix with duct tape and bailing wire.

heck drive it till the wheels fall off

 

[Wrench]

oh geez

Hell, I'm all for primo setup. I was just pointing out that the OP was asking for suggestions on fixing his overheating problem, and the thread morphed into a howto on installing dual stats.

Just throwing it out there . . .

 

[kennyw]

I forgot it's a plow truck

The main point your missing, he has no overheating problems when the plow is removed. The only affect the plow has is to block the air flow, so that makes a logical starting point for improvements. You need air to cool down the coolant in your radiator or it won't matter how many GPM your pump can handle. If that isn't enough, then he can start doing other mods in a logical order to go with it.

But being a plow truck probably means it isn't going to get every mod under the sun. If a free mod of locking up the fan fixes the problem, my guess is that is where the mods will end.

 

[85-m1028]

The main point your missing, he has no overheating problems when the plow is removed. The only affect the plow has is to block the air flow, so that makes a logical starting point for improvements. You need air to cool down the coolant in your radiator or it won't matter how many GPM your pump can handle. If that isn't enough, then he can start doing other mods in a logical order to go with it.

But being a plow truck probably means it isn't going to get every mod under the sun. If a free mod of locking up the fan fixes the problem, my guess is that is where the mods will end.

right, airflow!! maybe you can sit on the plow and talk into the front of the truck. It might be hot air but at least it'd be flowing!

 

[kennyw]

Have fun on vacation...

 

[tRustyK5]

right, airflow!! maybe you can sit on the plow and talk into the front of the truck. It might be hot air but at least it'd be flowing!

Is it holiday boredom? There must be a reason you seem to be single mindedly out to irritate and annoy everyone in this thread. Keep it up and you can spend your holiday time annoying people at other sites because this one won't be available to you.

Bob nailed the cause and the solution about 20 replies ago. Plow blocks air, and without spending a dime the fan can be locked to overcome the lack of airflow when the plow is on. problem solved, $$ spent = nothing. Better yet he managed to do so without coming across like a know-it-all asshole that equates money spent with how good the fix is.

Rene

 

[85-m1028]

Is it holiday boredom? There must be a reason you seem to be single mindedly out to irritate and annoy everyone in this thread. Keep it up and you can spend your holiday time annoying people at other sites because this one won't be available to you.

Bob nailed the cause and the solution about 20 replies ago. Plow blocks air, and without spending a dime the fan can be locked to overcome the lack of airflow when the plow is on. problem solved, $$ spent = nothing. Better yet he managed to do so without coming across like a know-it-all asshole that equates money spent with how good the fix is.

Rene

I understand it's a plow truck, however when my fan clutch locked on my truck on 30 miles left of a trip back from the mountains the dang thing was so loud I about parked the dang thing on side of the road and walked!

Drove me nuts!! These things are loud enough as it is!

My appologies for offering alternatives to your one size fits all solution!! you're worse than the government around here!!

If you want to discriminate against valid information that's your prerogative. I think it does this entire forum an injustice.

I can't count the times I've stepped on some old gruffs toes in the pursuit of viable information. I guess the cost will be my participation? How PC.

 

[kennyw]

The information is useful, to a point. But, it doesn't change the fact that you come across like an ass with his head stuck in the sand. That attitude is not welcome here. We can share different opinions with out the BS you brought to this thread. No one is telling you your information is bad or wrong. However, a lot of us know the original poster well enough to know he is not looking to spend $1000 upgrading a cooling system that works when the plow is off so we offered simple alternatives.

Put the information out there and let the guy spending the money decide what he wants to do with his truck. Enough said.

 

[tRustyK5]

The information is useful, to a point. But, it doesn't change the fact that you come across like an ass with his head stuck in the sand. That attitude is not welcome here. We can share different opinions with out the BS you brought to this thread. No one is telling you your information is bad or wrong. However, a lot of us know the original poster well enough to know he is not looking to spend $1000 upgrading a cooling system that works when the plow is off so we offered simple alternatives.

Put the information out there and let the guy spending the money decide what he wants to do with his truck. Enough said.

Exactly...

Rene

 

[85-m1028]

Well we're just gonna have to disagree, No need to sick the moderator on me. I would associate the heat problem with several factors.

The extra weight placed on the front of the vehicle pushing a load

The final drive ratio "axle gears" in particular

Transmission heat load, coolers are in the radiator in factory form.

Cooling system properly rated

Plowing in 4hi or 4low?

Air flow would be far down on my list possibles because it is not heavily impeded, telling someone to just lock the fan up to me is a bit like...

someone asking why the tires on the back of their blazer are very squished with 2000lbs in the back.

the cheap simple solution would be to pump the tires up to 80lbs

Is this so you can have a good a laugh when they post back that their rear tires blew out?

Sorry that's the best parallel I could come up with..

A fan upgrade, fan clutch, thermostat, high flow v-belt waterpump, all things that would be WAY lower than that $1000.00 number you're throwing around.