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H/O Waterpump VS. Stock

Read that article, now he is talking about the hd 8894035 pump.... Which one is that?? Is it the bolt fan type of 1997, or is it the 99.5 and up?? I want to optimize the cooling on both sides, Im going to call gm and get a price next monday......
 
Im with Rich on this one.

The HO pump not only gets more flow to the radiator BUTTTTTTTTTTT it surges more coolant through the block and heads to eliminate stagnant areas that can under hard running create steam pockets.

This is was and is the main reason that the heads crack. With more flow through the engine these spots of low flow are eliminated and with that goes many issues you dont need.

The radiators on these trucks are right on the ragged edge (as far as any extra cooling ability) When they start to plug up (with bugs outside and goop inside) their ability to handle the heat is over with and the issues start to happen.

A good custom all aluminum radiator with large tubes is the way to go.

Here locally a place called "Mac's" does a lot of custom stuff and they make radiators to cool and with enough overkill that they will continue to do so for many years with minimal maintenance.

Most larger cities are going to have a specialty shop that can and do offer these services.

The dual vs single stat thinking is a simple one.

The single stat can not "CAN NOT" flow the 130 GPM that the dual unit can.
GM would not have spent the $$$ to design and build these if the sible one would have done the job.

The flow through the single stat is pretty well maxed out at the 85 GPM rate.

When trying to push 130 GPM though the small opening of the single stat the velocity increases greatly causing a lot of turbulence and possibly airating the flow some too.

High speed flow does not always equal better cooling. The flow rate increase through the radiator is only about 7% where as the flow increase through the block is far greater.

One of the biggest issues was and is getting the fan to turn on so that the radiator can dump the heat.

The aftermarket fan clutches (Heath, Kennedy etd) help a lot as do the DMAX setups

Clean radiator, good fan clutch and a proper fan that will really howl and suck up all the bugs for miles around along with the HO pump and the dual stats will cool the fire breathing beast.

Just what ya wanted to hear HUH.

IMHO the HO pump is a waste of time and money if not coupled with the complete package.

As my rebuild on the Dahoooley comes to a close I intend to install a fresh radiator along with the dual stat Xover, HO pump, 180 Robert shaw stats and a low temp fan clutch.

I do not want any more crispy critters under my hood.

It is not that hard to cool a 6.5 even in the hot weather.

Best

MGW
 
DieselSlug said:
I dont know if you all remember the overheating issues i had last winter. I plow with a fisher minute mount, but starting last year i have been overheating going up steep grades. So i cleaned the rad. and flushed EVERYTHING. I made sure of it. And bought a new gm dealer ac delco stat, i know im going to get the h/o pump for sure now, thnx for the advice. Im still debating on the dual t stat.... I really want this thing to have AWESOME cooling system...... I better read that maxx torque article next.... I will read on my lunch break today.... IM going to call napa and have them order it..... As for the t stats i am undecided, mainly it cost more money...... WIll the dual t stat housing line up with my coolant hoses? The only place i see i could buy them without the whole frekin kit is peninsular diesel...
Click to expand...
The duall t stat crossover will interfere with the tensioner bracket on your 94
 
Not to get in a whizzin contest, over cooling theory and rates of flow vs what GM did with dual stat & 130 gpm, I'll offer up this point.

The 130 gpm dual stat set up was modeled for a 6.5 making 195 flywheel HP and towing at operators manual published towing limits, and some steady state speed which most of us probably don't drive at; so there is a distinct possibility that the flow model is incorrect for those that do more than that with our trucks.

My 98 Burb new to me in 2006 was overheating in traffic, I deep cleaned the rad and things got better, but I was not happy with it still, so I bought the full H2O kit from Heath, new pump ala 6.2 latest style IIRC, swapped to a single stat from the dual it came with, tweaked down heater bypass nipple, added plastic fan/spin on clutch, and I could not be happier or running cooler.

Not much special about the Burb power adder wise reflash, PMD remoted, TM, & 4" exhaust it's a people hauler, my K1500 all mods in sig including balance flow (not really necessary now for most 6.5ers per Bill if going with his latest H2O kit), never gets over 195F coolant, 100F days moving 18K# loads, (that one is still 97+ GM statted/pumped)stock rads though on both vehicles.

My point is THE GM fix may not be THE fix, as most aren't running to that power band anymore, IMO if one looks at the flow calcs GM used I think maybe 130gpm is too much flow, that flow is so fast that proper time in rad for water is on ragged edge for proper heat xfer to occur, and that we know 95gpm is not enough flow , maybe better flow is 110-120 gpm.

I don't know what Bill's single stat set up is flowing, but remember this was on the LSR at Bonneville in desert salt flat, and keeping things cool to 153 mph, so something to consider.
 
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Good points Doc

The calcs that GM used no doubt were figured for "Normal driving"

The biggest benefit I see is more air through the radiator to get the heat out of the coolant and to do it before the beast starts to cook.

MGW
 
I would second MGW's thoughts on increased flow volume - specifically through the head passages. The passages nearest the combustion chamber & exh ports have temps far above the coolant boiling point.

My theory is it takes lots of flow to continually remove the heat input from those surfaces fast enough so the coolant doesn't boil/flash to steam in certain pockets. I think this explains the sudden coolant system pressure rise when a hot engine is shut down without cool down - eg. an overheating engine puking some coolant out the overflow upon shut down.

Now getting rid of all that heat from the rad is another story.

The 88894035 water pump crosses to an AC-Delco # 251-603. Simply searching 251-603 pulled up pictures that show the later, screw on fan clutch water pump.
 
Turbine Doc said:
Not to get in a whizzin contest, over cooling theory and rates of flow vs what GM did with dual stat & 130 gpm, I'll offer up this point.

The 130 gpm dual stat set up was modeled for a 6.5 making 195 flywheel HP and towing at operators manual published towing limits, and some steady state speed which most of us probably don't drive at; so there is a distinct possibility that the flow model is incorrect for those that do more than that with our trucks.

My 98 Burb new to me in 2006 was overheating in traffic, I deep cleaned the rad and things got better, but I was not happy with it still, so I bought the full H2O kit from Heath, new pump ala 6.2 latest style IIRC, swapped to a single stat from the dual it came with, tweaked down heater bypass nipple, added plastic fan/spin on clutch, and I could not be happier or running cooler.

Not much special about the Burb power adder wise reflash, PMD remoted, TM, & 4" exhaust it's a people hauler, my K1500 all mods in sig including balance flow (not really necessary now for most 6.5ers per Bill if going with his latest H2O kit), never gets over 195F coolant, 100F days moving 18K# loads, (that one is still 97+ GM statted/pumped)stock rads though on both vehicles.

My point is THE GM fix may not be THE fix, as most aren't running to that power band anymore, IMO if one looks at the flow calcs GM used I think maybe 130gpm is too much flow, that flow is so fast that proper time in rad for water is on ragged edge for proper heat xfer to occur, and that we know 95gpm is not enough flow , maybe better flow is 110-120 gpm.

I don't know what Bill's single stat set up is flowing, but remember this was on the LSR at Bonneville in desert salt flat, and keeping things cool to 153 mph, so something to consider.
Click to expand...


The MaxxTorque article on the LSR said it used the early water pump for the least parasitic hp loss.
 
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Going at 120+ mph probably aids in cooling a bit i would think, considering that vehicle probably is as light as possible, its more about fighting wind resistance, which aids in cooling, that hauling weight.

I think a custom overkill radiator is a great idea for those who have troubles when their fan clutch is engaged.
 
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The article claimed the HO pump took an additional 10 hp to drive at high rpms. Mostly mentioned that as it's good to know both pro's & con's of these alternative parts.

Would expect most of us on the forum are happy to trade a few hp if the HO water pump improves durability/longevity.

There was some good info in that article for anyone considering building a 6.5. Some things they did may not be so applicable to daily driver/tower truck, but still a lot of insights & ideas they've gained over the years. It's specifically the stuff that they've tested & have empirical experience that the ideas have worked on several engines.
 
SmithvilleD said:
You might check out the latest issue of MaxxTorque. It has an article by Bill Heath specifically on 6.5 cooling upgrades: interesting details on how different setups flow. Both overall flow rate, & how equally (or not) they flow to each head.

You can read it on the MaxxTorque website.
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Thanks for the suggestion. After reading the article, I would also like to know if we can get the water pump alone, just for starters.
 
You will also need to get a fan clutch. The extra heavy duty one he is talking about in the article is spin on fan clutch only. Not the 4 bolts that hold your fan clutch to water pump.

You might be able to get them to sell you the pump and fan clutch w/o fan blades.
 
You will also need to get a fan clutch. The extra heavy duty one he is talking about in the article is spin on fan clutch only. Not the 4 bolts that hold your fan clutch to water pump.

You might be able to get them to sell you the pump and fan clutch w/o fan blades.
 
See i didnt want to switch to the screw on job, i just bought the fan kit with the four bolts from heath. How hard is it to switch to the dual crossover???. I NEED this thing to cool the best it can with a plow blocking my radiator...... So i cant use the 88894035 then, like i wanted to.... I need to find out how the fan attaches to the napa one for the 97 model...... I need to stick with the four bolt dmax fan, spent too much money on it to just throw it out.... and about that whole heath kit, i like it but im still stuck with my fan, and its like 400+ if i recall......
 
Ratman said:
Whether you go dual-stat, -or decide to stay with single, -the HV 4.5" trim pump is definitely what you are after.

I love my duals, -but that's just me.

I'm famous for not going with the grain, -dual stats it is. :thumbsup:

Never a problem, -thing never goes above 185, -even whippin' it with a 6,000 lb trailer pulling a mountain pass.

Radiator is CLEAN!!!!

A clean radiator is MORE important than an HO pump, a duramax fan, dual t-stats, etc.

A clean radiator should be the very first thing on a 6.5'ers cooling system maintenance/upgrade "program".
Click to expand...
Yup,i even removed the whole AC shebang(was f'ed anyway),havent seen it over 180.
 
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