Which Brand HO Pump?

[midniteplowboyy]

Were the pics comparing the 94 to a 98 pump? If so you can tell from about ten feet away once you know what to look for. Look at the distance between the impeller and bolt holes, the 98HO pump has about a half inch bigger impeller than the 94. You can tell from the outside also but its alot harder.

 

[vail426]

No, they were 97 up and 99 1/2 up. One was at rock auto, but I forget where the other was. The one at rock auto was a CARDONE SELECT Part # 5511411. But being an aftermarket, who knows. My truck runs perfect and eventually I will do the latest pump, clutch and Duramax fan. I maintain the heck out of it and I want to cover all the bases.

 

[buddy]

I and I know others with the low flow pump and temps never go over 210. I dont tow a lot, but I do beat on it, with 20psi boost and WOT runs often to 120+mph and it never gets over 195. I didnt even do any fan clutch mod, just put a heavy duty clutch and DMax fan on, and I dont think the clutch ever kicks in. But I do only run 10% antifreeze and I dont think enough people understand this benefit enough. I thought Heaths article pointed out the difference in flow from 97-99 pumps and 2000 pumps, not sure he mentioned the low flow, and why would he use it on his own racer truck then?

 

[Acesneights1]

Kennedys fan does not fit the 99.5+ WP's and he does not make one for them. The Hayden SD clutch can be gotten at any NAPA but all of this stuff is a band aid. Someone needs to step up to the plate and get an electrically controlled Horton style clutch built for our trucks. That is EXACTLY what they need.

 

[midniteplowboyy]

I and I know others with the low flow pump and temps never go over 210. I dont tow a lot, but I do beat on it, with 20psi boost and WOT runs often to 120+mph and it never gets over 195. I didnt even do any fan clutch mod, just put a heavy duty clutch and DMax fan on, and I dont think the clutch ever kicks in. But I do only run 10% antifreeze and I dont think enough people understand this benefit enough. I thought Heaths article pointed out the difference in flow from 97-99 pumps and 2000 pumps, not sure he mentioned the low flow, and why would he use it on his own racer truck then?

Maybe its the marine injectors, I dont know, but mine will with the 98HO pump. My truck is a lil heavier than yours though, plus spinning 800 pounds of tires/wheels.

I dont think its an antifreeze mix problem, the coolant must be picking up heat to be able to transfer it to the gauge senders. Dont think its a fan problem since rear head coolant temps can can be 100ºF cooler(yes, one hundred). About always the rear head temps run 150ºF and cooler with the HO pump, the original low flow pump rear temps would run 150-200ºF, both pumps stabilized to stat temp @ idle on all gauges.

I think heath used the low flow to save HP, plus he's spinning it to 5500rpm.

 

[buddy]

Sounds like you have a good amount of data to compare the pumps, do you have a consolidated list of data or comparison already written up? Id love to see a chart with pump type and which head was what temp while the other was this temp and at different load levels, idle, cruise, tow.

As far as I can tell Heaths testing was a side by side comparison of the 97-99 vs the 2000 pump.

 

[vail426]

I am getting confused. My understanding is the latest pump balances the coolant flow between heads so that the passenger head does not get hotter than the driver's. That is all I care about, plus you get more GPH than the '94-'95 pumps. Where are the heads the hottest? In the rear further from the radiator or in the front closest to the radiator? Seems to me the rearmost would run warmer. If not, why did they offer the "balance flow system"?:???:

 

[midniteplowboyy]

The original 92-96 pump did run hotter on the right side than the left on my 93. Temps were higher at all locations and conditions, except for maybe extended idle then about the same IIRC.

I bought the 98 pumps at Bumper-to-Bumper, cant remember the brand name, new not reman. Maybe they used the 2000 model housing/impeller, I dont know, but both sides cool about the same and alot better than original.

Or maybe the 2000 pumps are the same as the 98 except the thread on fan clutch and its a marketing ploy to sell more parts(fan and clutch also). Funny how a few years ago everybody saying oh no you cant use a 98 waterpump on an earlier one without the dual theremostat housing or you'll blow the core plugs out, wonder how many dual stat housings got sold. Now the big ticket is the single housing after everybody has switched, hmmmm.

I wish some one would compare the two later pumps side by side, I would but my local parts store would have to order them and send them back.

Atleast I cured all my overheat problems for the time being(broken crank), lol.

 

[SnowDrift]

I and I know others with the low flow pump and temps never go over 210. I dont tow a lot, but I do beat on it, with 20psi boost and WOT runs often to 120+mph and it never gets over 195. I didnt even do any fan clutch mod, just put a heavy duty clutch and DMax fan on, and I dont think the clutch ever kicks in. But I do only run 10% antifreeze and I dont think enough people understand this benefit enough. I thought Heaths article pointed out the difference in flow from 97-99 pumps and 2000 pumps, not sure he mentioned the low flow, and why would he use it on his own racer truck then?

120 mph - That makes me laugh. Not because I don't believe you, because I absolutely do believe you. It makes me laugh because if I do 75-80, it feels like the whole truck is going to blow apart.

 

[buddy]

My truck seems pretty solid, rides real smooth over 100mph, the only problem I have is the mirrors turn in when I get somewhere over 100mph. The engine sounds real smooth and nice too when wunning with the ATT. With the GM4 it doesnt sound happy at all but it still gets there. I ditched my Banks exhaust, its like 3" pipe with a Cat, that wouldnt let the ATT spool over 5psi, although that huge muffler was silent.

 

[handcannon]

Hey guys, I like the info being shared here. It's great!

I'm doing some reading to catch up after being gone for a few days. A GM part number was given a few posts back for the 2000 HO pump that Heath says has the best flow. Last week in my researching I found out that number has been superceded. The old GM number was 88894035 and the new number is 19168609.

Update
I just got back from a 4 day family camp with the church. Wasn't that long of a drive, maybe 45 to 50 miles. The temps today on the way home were in the low to mid 80's. It was slow driving, crooked roads, up and down a lot, but no real long hills. I never saw the temps go over about 205*.

Since the trip didn't really give the latest fan clutch mod much of a test I decided to take a detour just before getting home. I took the I-5 freeway up over Illahe Hill to see what would happen. Illahe is just over a mile long and has just enough grade to slow down the big rigs a bit. I got stuck behind a truck going just over 55 MPH just before hitting the hill. I stayed behind him down to just under 50 MPH. I never saw the temps climb over 205* here either. I never heard the fan kick in either.

I'm over 90% convinced the new fan clutch is a dud. I've got a DE 4" exhaust which really makes the cab resonate when pulling hard up hills. I'm now wondering if that resonance is masking when the fan comes on, if it does come on. And, if it does come on it has to be weak. I'm leaning real hard towards the Heath fan clutch which puts me in a real dilemma. I don't want to spend the money for the Heath clutch just to put it on the stock 94 pump. The 2000 HO pump is not cheap either. The stealership wants $440 for it (OUT of the question), and I think Rockauto is around $280. I guess I'll have to load up all the scrap metal that has collected around here and see if I can come up with enough to do both.

Now, back to the discussion at hand. If anybody has some solid info comparing the early HO pumps (98 like midniteplowboyy) to the 2000 HO pump I'd sure like to see that. It might make my decision about what to do easier.

Don

 

[mike98dually]

Much appreciate the info on this site. Many times viewed/first time posting. Recently purchased a 2000 spec pump from napa, part #44056 for $184.00. Could not see any difference between this unit and original pump. That is until I tried to reinstall the alternator bracket. Would not fit over the protrusion that mates to the right side block coolant passage. Had to remove a significant amount of metal from the bracket to get the fit and alignment for serpentine belt. Can only assume that this is the improvement to increase the right side flow. Unfortunately have not had opportunity to do a road test with a load in tow.

 

[bobbiemartin]

I'm over 90% convinced the new fan clutch is a dud. I've got a DE 4" exhaust which really makes the cab resonate when pulling hard up hills. I'm now wondering if that resonance is masking when the fan comes on, if it does come on. And, if it does come on it has to be weak. I'm leaning real hard towards the Heath fan clutch which puts me in a real dilemma. I don't want to spend the money for the Heath clutch just to put it on the stock 94 pump. The 2000 HO pump is not cheap either. The stealership wants $440 for it (OUT of the question), and I think Rockauto is around $280. I guess I'll have to load up all the scrap metal that has collected around here and see if I can come up with enough to do both.

I bought a Hayden Heavy Duty Truck fan clutch (which is above the severe duty) for $111.00. Peninsular use to sell take off water pumps with the spin on pulleys for $65, you might give them a call and see if they still have any. That is what I run on my Suburban with a Duramax fan and it cools very well.

 

[Acesneights1]

Much appreciate the info on this site. Many times viewed/first time posting. Recently purchased a 2000 spec pump from napa, part #44056 for $184.00. Could not see any difference between this unit and original pump. That is until I tried to reinstall the alternator bracket. Would not fit over the protrusion that mates to the right side block coolant passage. Had to remove a significant amount of metal from the bracket to get the fit and alignment for serpentine belt. Can only assume that this is the improvement to increase the right side flow. Unfortunately have not had opportunity to do a road test with a load in tow.

It's just a slight difference in the casting being an aftermarket vs GM. I had the same problem and I was replacing the WP on my 2000 with a 2000 WP and had to grind that area down a little to fit.

 

[SnowDrift]

I had mentioned, earlier, that we had a small tow coming up this weekend and I didn't take the time to go across the scales, but I'm guessing we were only at about 12,000 lbs. or so and pulling the hills in southern Ohio with the slide in camper, tandem trailer, two ATVs, gear and 5 people. I set the cruise at 60 and 65, depending on the speed limit and saw 15 psi, sustained for around 45-60 seconds with the A/C on. My EGTs hit 700 deg. and the temperature gauge started to raise a little above where it normally sits, but recovered quickly as we crested the hill and it never offered to go back up. The EGTs stayed right at about 550 with the A/C off and closer to 600 with the A/C on.

From the driver seat, I didn't see any negative effects from the Balance Flow system and I'm glad it's there because I know the water temps in the heads were more reasonable than usual.

 

[handcannon]

Just to update things, I ordered a new 2000 pump from Carquest. Yesterday evening I removed the old pump and during cleaning gasket surfaces and such I ran into a major problem with the pump. The impeller is setting proud of the casting be about 1/16th". No way that will go in there! Grrrr!!!!!

The biggest visible difference between the old and new pumps is the impeller. The old pump has a 4" diameter impellor with three half circle shape notches, equally spaced around the outside circumference. The new pump has a 4 1/4" diameter impeller with no notches.

Don

 

[buddy]

Just to update things, I ordered a new 2000 pump from Carquest. Yesterday evening I removed the old pump and during cleaning gasket surfaces and such I ran into a major problem with the pump. The impellor is setting proud of the casting be about 1/16th". No way that will go in there! Grrrr!!!!!

The biggest visible difference between the old and new pumps is the impellor. The old pump has a 4" diameter impellor with three half circle shape notches, equally spaced around the outside circumference. Th new pump has a 4 1/4" diameter impellor with no notches.

So youre saying the 2000 pump will not fit onto your timing cover?

Anyone else run into this issue?

 

[handcannon]

No. The pump apparently has a manufacturing flaw. The impeller is not fully seated as I think it should be. It is not flush with the surrounding gasket surface the way the old pump is. I'm leaving for town in a few minutes to take it back to Carquest.

Don

 

[vail426]

I had to open this thread as I was looking around and found this...

https://ssl.zoovy.com/expeditionimp...rpump-251-590---GM-88894036---65-Diesels.html

I can't afford the spin on set-up so this is what I settled for. Sure can't beat the price. Take a look. Back in September 2010, my son in law borrowed my truck and some dummy took a left turn in front of him and the result was 8100 bucks worth of damage:. As fate would have it, I still had collision coverage on the truck. The insurance company gave me 5900 bucks which I felt was fair. So I brought it to a reputable shop and I had it back in 3 weeks. Of course I had to make up the difference, but where do you buy a diesel pick up that you know like the back of your hand for 2200 dollars? It was an easy decision. Anyway the radiator fan was bent and the clutch damaged so I got a 20' kennedy fan and hayden clutch. Of course the water pump survived and is still on the engine. The radiator, support, condenser, oil coolers, hood, right fender and inner right fender,bumper and all associated parts did not survive. Oh, the PMD was behind the bumper and is now behind the new bumper. So I could not pass this up. When the time comes I have a new pump for the occasion. Thought I would share this deal for others...

 

[mitchedo]

I bought a Hayden Heavy Duty Truck fan clutch (which is above the severe duty) for $111.00. Peninsular use to sell take off water pumps with the spin on pulleys for $65, you might give them a call and see if they still have any. That is what I run on my Suburban with a Duramax fan and it cools very well.

I realize this thread is old, but plenty of folks (like me) end up here on search.

I purchased a Peninsular takeoff pump when I put my engine back together. It failed after fewer than 6000 miles. ...leaking out the weep hole. Of course, it's taken me 2 years to put that many miles on my truck, so maybe it was related to the pump sitting still for months on end. I also don't think it's the right pump. I think it's built for a naturally-aspirated 6.5. I'll know more when I yank it off in the next few days.