Any thoughts for water pump upgrade for gen iv 6.2 yukon

[kaleburditt]

I have 08 yukon denali with the 6.2 and kept vvt. I stroked it and supercharged it. I got exactly what i wanted and that was to tow up hill and across country in converter lockup. Problem is overheating. Obviously 1600 rpms aren't enough to keep it cool enough. For that matter neither is 2200. I replaced the radiator with a monster. Added external transmission cooler and in the process of oil cooler as well. But it still overheats. I think I just need extra air flow or water flow and I would be good. My water pump outlet comes out the top of the pump and with vvt, its apparently a different mounting as well. Has anyone had success with aftermarket performance pumps that specifically work better at the lower rpm? I never go over 4000 rpms so even an electric pump or smaller pulley would work? Maybe use an LS3 pump and get a new water return hose?

Edelbrock claims they don't make one. March doesn't make pulleys for it. FlowKooler are currently out of stock and its only for an ls2, and meziere doesn't seem to have the appropriate application either.

With a L92 I am having a difficult time sorting through the applicable cross references on which water pumps I can use. OR even if i need one. There doesn't seem to be definitive answers to flow rates of oem and after market pumps especially at closer to the idle and cruise ranges. If I could get away with just upgraded electric fans I would take that option as well although I see unconfirmed that stock flows 5500 cfm already.

 

[Doubeleive]

I bought a used OEM dual 700w system (k5l) and then I put new 700w motors in it just to be on the safe side, I can't say it cools any better or not there is a difference the shroud is thicker and the motors are bigger, they are a smidge louder when running high speed but not excessive enough to hear it in the truck. none of the parts are swapable with the 500w fan system.
it's all plug-n-play no other changes are needed I confirmed with the dealer the relays are the same for the 500w and 700w system, electrical connectors are the same also.
https://www.ebay.com/itm/Radiator-C...AOSwgbdcG~8J:sc:FedExHomeDelivery!95219!US!-1

 

[ivin74]

I have 08 yukon denali with the 6.2 and kept vvt. I stroked it and supercharged it. I got exactly what i wanted and that was to tow up hill and across country in converter lockup. Problem is overheating. Obviously 1600 rpms aren't enough to keep it cool enough. For that matter neither is 2200. I replaced the radiator with a monster. Added external transmission cooler and in the process of oil cooler as well. But it still overheats. I think I just need extra air flow or water flow and I would be good. My water pump outlet comes out the top of the pump and with vvt, its apparently a different mounting as well. Has anyone had success with aftermarket performance pumps that specifically work better at the lower rpm? I never go over 4000 rpms so even an electric pump or smaller pulley would work? Maybe use an LS3 pump and get a new water return hose?

Edelbrock claims they don't make one. March doesn't make pulleys for it. FlowKooler are currently out of stock and its only for an ls2, and meziere doesn't seem to have the appropriate application either.

With a L92 I am having a difficult time sorting through the applicable cross references on which water pumps I can use. OR even if i need one. There doesn't seem to be definitive answers to flow rates of oem and after market pumps especially at closer to the idle and cruise ranges. If I could get away with just upgraded electric fans I would take that option as well although I see unconfirmed that stock flows 5500 cfm already.

Try asking the folks on performancetrucks.net those folks are very knowledgeable.

 

[thompsoj22]

Just a thought, I have the 08 same vehicle and have allways seen the front grill as obstructive to ram air effect. All those holes have got to disrupt the air flow and at a minimum slow it down. I have been looking at the stock GMC sierra grills that have the lateral bars and i believe the "ram airflow" would be improved at speed.Also noticed that on vehicles with viscous clutch fans when you are going downhill and off throttle the engine temp will drop but on electric fan setup it does not have the same effect, in fact going downhill and off throttle the temp gauge will not move. You are supercharged so a few HP to drive a viscous fan wont hurt your rig, Maybe eliminate the electric fan setup and determine if your temps would be more manageable. Moving the coolant more rapidly wont work, you have to reduce the temp of the fluid delivered to the engine, ie' more airflow through the radiator.

 

[kaleburditt]

I bought a used OEM dual 700w system (k5l) and then I put new 700w motors in it just to be on the safe side, I can't say it cools any better or not there is a difference the shroud is thicker and the motors are bigger, they are a smidge louder when running high speed but not excessive enough to hear it in the truck. none of the parts are swapable with the 500w fan system.
it's all plug-n-play no other changes are needed I confirmed with the dealer the relays are the same for the 500w and 700w system, electrical connectors are the same also.
https://www.ebay.com/itm/Radiator-C...AOSwgbdcG~8J:sc:FedExHomeDelivery!95219!US!-1

i went ahead and bought these. didn't know there were more powerful drop in fans available. and it seems to be about the best i can get before having to make drastic changes to install a mechanical fan.

Just a thought, I have the 08 same vehicle and have allways seen the front grill as obstructive to ram air effect. All those holes have got to disrupt the air flow and at a minimum slow it down. I have been looking at the stock GMC sierra grills that have the lateral bars and i believe the "ram airflow" would be improved at speed.Also noticed that on vehicles with viscous clutch fans when you are going downhill and off throttle the engine temp will drop but on electric fan setup it does not have the same effect, in fact going downhill and off throttle the temp gauge will not move. You are supercharged so a few HP to drive a viscous fan wont hurt your rig, Maybe eliminate the electric fan setup and determine if your temps would be more manageable. Moving the coolant more rapidly wont work, you have to reduce the temp of the fluid delivered to the engine, ie' more airflow through the radiator.

which brings me to this. i considered this but i would have to completely change my intake to accomodate the mechanical fan and shroud as the lsa supercharger TB is lower and points to the driver side. this is my last resort option. I was thinking of the front grill too and considered modifying it to include some sort of under bumper scoop to aid in air delivery. also changing to a mechanical fan would require replacing the water pump and now you are definately trying to find water pumps not made for the vvt application. also that goes back to a possible water pump upgrade.

it should be noted that GM states that up to 250 degrees is acceptable for towing and i am only allowing it to get to 240. but i tow so much that i can't help but think that if you run an engine during its entire lifetime at 240, it's not good.

thanks for the speedy replies guys.

 

[Doubeleive]

i went ahead and bought these. didn't know there were more powerful drop in fans available. and it seems to be about the best i can get before having to make drastic changes to install a mechanical fan.



which brings me to this. i considered this but i would have to completely change my intake to accomodate the mechanical fan and shroud as the lsa supercharger TB is lower and points to the driver side. this is my last resort option. I was thinking of the front grill too and considered modifying it to include some sort of under bumper scoop to aid in air delivery. also changing to a mechanical fan would require replacing the water pump and now you are definately trying to find water pumps not made for the vvt application. also that goes back to a possible water pump upgrade.

it should be noted that GM states that up to 250 degrees is acceptable for towing and i am only allowing it to get to 240. but i tow so much that i can't help but think that if you run an engine during its entire lifetime at 240, it's not good.

thanks for the speedy replies guys.

let us know if the 700w fans help any.

 

[randeez]

Fans wont do anything if your overheating while moving, theyre typically not even on if your moving.

I would start with assessing the condition on the stock parts, how many miles on radiator-is the coolant clean dexcool or just some brown slurry, verify thermostat is working, how is the belt routed with the supercharger? Does the water pump not have proper belt wrap to spin under load?
Check the tune also, a 1600rpm cruise shouldnt be stressing anything if there is too much timing in it under that much load itll heat the engine up also

Do some gears if you're only towing, itll help two fold

 

[thompsoj22]

Fans wont do anything if your overheating while moving, theyre typically not even on if your moving.

I would start with assessing the condition on the stock parts, how many miles on radiator-is the coolant clean dexcool or just some brown slurry, verify thermostat is working, how is the belt routed with the supercharger? Does the water pump not have proper belt wrap to spin under load?
Check the tune also, a 1600rpm cruise shouldnt be stressing anything if there is too much timing in it under that much load itll heat the engine up also

Do some gears if you're only towing, itll help two fold

Are you sure on the "fans arent even on if your moving" statement? Id bet those fans are on constantly while the op is towing? but the belt wrap on the pump is a good consideration. Read the opening thread, the post defines skills/knowledge so i doubt there is brown slurry in the new radiator. I dont know how much weight he is towing and the trans is definitley adding heat to the radiator. I agree with the K5L fans as the next logical part to throw at it. plug and play is no stress and no mods!

 

[randeez]

you have my word.

even if theyre on, they arent doing much. use a simple online cfm calc 34x22" radiator (duct size), call the stock fans 6000cfm rated. it shows as moving the air at >10mph
or try putting your hand behind your fans when theyre on high and feel the force, then drive 20, 30 ,40, 50mph with your hand out the window and which is more powerful?

 

[iamdub]

Any chance your thermostat could be stuck open?

 

[randeez]

how about the head gaskets? if not installed correctly they will restrict the coolant flow through the head

im mostly just throwing out suggestions, no disrespect. the gm ones i use are symmetrical one lays on flat with stamped part number tab up with a "front" stamped in it ,the other bank "front" and all the stampings go face down

 

[97audia4]

OP Interested in what radiator you went with?

If you are towing at 1600 rpm that is putting a huge strain/ load on the engine.

 

[kaleburditt]

Fans wont do anything if your overheating while moving, theyre typically not even on if your moving.

I would start with assessing the condition on the stock parts, how many miles on radiator-is the coolant clean dexcool or just some brown slurry, verify thermostat is working, how is the belt routed with the supercharger? Does the water pump not have proper belt wrap to spin under load?
Check the tune also, a 1600rpm cruise shouldnt be stressing anything if there is too much timing in it under that much load itll heat the engine up also

Do some gears if you're only towing, itll help two fold

let us know if the 700w fans help any.

Fans wont do anything if your overheating while moving, theyre typically not even on if your moving.

I would start with assessing the condition on the stock parts, how many miles on radiator-is the coolant clean dexcool or just some brown slurry, verify thermostat is working, how is the belt routed with the supercharger? Does the water pump not have proper belt wrap to spin under load?
Check the tune also, a 1600rpm cruise shouldnt be stressing anything if there is too much timing in it under that much load itll heat the engine up also

Do some gears if you're only towing, itll help two fold

Being a a six speed awd I am gonna wait on the gears.

Timing? I'm hearing too retarded is gonna add heat. So I've been adding several degrees of timing under all conditions. It seems that has helped considerably. Especially since it's a real slow overheat. Like it take 20 minutes to overheat.

Belt wrap is good. Comes in at the twelve oclock and leaves at the two oclock. Ccw. But I'll revisit it again maybe with some emory cloth.
Thermostat was new when I rebuilt it and again with a 160. I'll be going back to a 170 as the 160 is a touch cold for me under normal driving conditions. I did try going without as well. Yes that was a mistake.

I have a higher than normal water ratio. I have one of those bulb testers and I don't really go to below 0 degrees so that's maybe 25 percent. It's very faint in color. Added a bottle of water wetter as well for the corrosive properties.

As for the fans spinning while moving. So yes they do as I can turn them on manually with hptuners. I currently have them at 100 percent at 180 degrees. That is also why I was enquiring about water pumps. Or even a high flow thermostat. The radiator is brand new and bigger than stock and I have a ton o stuff in front of it. So I could be moving a hundred miles an hour and I think between the grill, HX, oil and trans coolers,ac condenser, and power steering cooler I don't think I have much in laminar air flow. I even tried lining up everything as much as possible. I really just think it needs a little helping hand. 40 percent more power in the airflow or 12 percent more water flow should do it.

 

[kaleburditt]

OP Interested in what radiator you went with?

First I went with one from gmpartsgiant.com. they are not OEM! The radiator i received was 1 inch and bent. The OEM is 1 3/16. I sent it back and they charged me a restocking fee! F those guys. Then I went with radiator express. I like the way these guys are set up. Full aluminum, double the size all tig welded with oil and trans cooler. Or should I say warmer.

If you are towing at 1600 rpm that is putting a huge strain/ load on the engine.

Even with tow haul mode on sometimes it just cruises in 6th. I try to keep it in 5th up to 65 or so. In 6th at 70mph it's only maybe 25 percent throttle at 80 kpa. This thing tows like a diesel.

 

[kaleburditt]

how about the head gaskets? if not installed correctly they will restrict the coolant flow through the head

im mostly just throwing out suggestions, no disrespect. the gm ones i use are symmetrical one lays on flat with stamped part number tab up with a "front" stamped in it ,the other bank "front" and all the stampings go face down

No fair question in fact I'm questioning it myself but not direction so much as wrong kind. I went with ls9 head gaskets as they were .054 and not .040. I think those are the numbers at the top if my head. I remember the coolant holes looking kind of small but these are the head gaskets for a 638hp crate motor so..

I tried looking through my photos to double check but I don't see any. Isn't there a tab you can see right above the exhaust?

 

[randeez]

Yep, should be over 3 and 4 ex ports

 

[Woodblocker55]

What are you towing what's the weights ? 12,000 GCWR. ?

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[hagar]

Once you go stroker and supercharged it creates so much more heat energy it becomes hard to keep it under control while loaded.
I have been through it many times on corvettes where even with aftermarket dewitts radiators and engine oil coolers, once under load, you can watch both temps climb until you unload it, then it levels back out.
The best way to help it is to make sure the incoming air through the front is forced into the radiator via shielding. The effect of having all the air funnelled then forced through the rad at highway speeds is greater than any fans you could ever add.
Do you still have all your factory air deflectors installed after doing the stroker? All those little rubber floppy shield in various spots behind the bumper?
If you dont, start there. If you do, grab some plastic sheeting and some snips, and go to town building as sealed of an air funnel as possible into the rad from any front openings you can. Tape all thevl seams and everything.
Its truly amazing how effective funneling all that air is.

 

[kaleburditt]

let us know if the 700w fans help any.

The one in the link was exactly what I had. And I do not have the k5l option so they are the 500 watt motors. The research is scant but it should be 5/5 or 7/9 blades. And the motors are not interchangeable. The 5/7 is what I ordered and they are the wrong ones for anyone who finds this post 2 years from now. I'm bracing for a fight with that ebay guy as he had them posted as k5l fans.

 

[kaleburditt]

What are you towing what's the weights ? 12,000 GCWR. ?

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I've hit the 12 mark towing my humvee so that must be it right? Nope. I started on the quest to fix this for good when it had all these problems when my 1200 lb trailer was empty. That did it for me. Granted it's the shape of a parachute.