[BigIron.45]

I am going to replace my water pump probably this weekend, it has started peeing all over the place since I had the heater core replaced and the system flushed and filled. Money prevents a full 2 thermostat 130 gpm pump system upgrade at this time. Question is should I get the 130gpm pump now and try to get the 2 themostat crossover and such later or go with an 87gpm pump and get Heath's Balance-Flow when money permits also can I just put a WP from a '97 on it or are they too different?

 

[nickg]

My 95 has the HO pump with the single thermostat (I think all the 97's have the HO pumps) and I towed my 25ft 5th wheel from Edmonton Alberta to Yarmouth Nova Scotia (one province short of driving clear across Canada) this past summer and my temp gauge NEVER went over 1/2 way even when the outside temp was 30 C plus.
I'd install the HO pump now and do the other stuff later IF you have overheating issues

 

[kimagine]

Do all the different water pumps for the 6.5's all bolt up the same way? I'm wondering if the 97 HO water pump would work with my 93?

Thanks,
Mark

 

[BigIron.45]

I am wondering the same thing. ~50$ for a local '97 vs. $109+ship/hand. for a vendor HO for the '94

 

[DavidPhillips]

Yes it will fit, and you don't need to worry about the crossover.

The pump design will output the same pressure no matter what restriction there is, so it will flow whatever the thermostat will allow.


For the other parts when your ready to upgrade look for AC-Delco crossover, and thermostat housing.


The impeller part of the pump is noticeably thicker on the 130 pump.

 

[gmctd]

The 130gph waterpump impeller is over 1/4" larger in diameter than the 85gal impeller - NAPA carries the identical brand as oem GM, so you can compare the pumps there - look for an HO or HD on the upper front housing, or compare impeller sizes, '95 to '98.

Should be seperate part numbers for standard '94-95-96 maybe '97, and for sure HO '98

All bolt up, the same.

 

[BigIron.45]

ok before I spend the $$ got one more stupid question. I noticed on the parts houses websites that a "bypass hose" is two completely different animals seemingly. (at least according to them) will I be able to use my stock '94 hoses or am I going to have to frankenstein them to use a '97 water pump?
Just want to make sure I get it absolutely 100% perfect the first time otherwise the wallet (read: wife) won't let me do squat to it again unless it is a bone stock 1:1 replacement that requires less tools that you find on a leatherman. she don't like spending money that doesn't work

And thanks for all the info so far!!

 

[4doorTAHOE6.5TD]

Here is what GM has to say :It's a mistake to install a 130 GPM WP without installingthe dual thermostat crossover. GM discovered that under just the right conditions ,coolant pressure could loosen soft plugs or cause coolant cavitation due to an inadequate flow capacity of a SINGLE THERMOSTAT. Two thermostats are necessary to handle the increased flow rate of the new 130GPM water pump & allow your engine to benefit from more coolant flow. This is what you tell the wallet. "The new water pump REQUIRES these additional parts". " It must be done" NOW !!! LOL

 

[oil burner]

GM used the HO waterpump on the '97 and up P-30 step van chassis w/6.5L n/a diesel using ONLY A SINGLE T-STAT. There are sevreral where I work that were purchased new and came from the factory that way. To date they have not lost a freeze plug or blown a radiator seam. I had an HO pump on a '91 6.2L p/u that blew the Radiator seam twice, replaced the original "Harrison" rad with a "Modine" and never again had any problems with the cooling system. So it will work to use a HO pump with a single t-stat,but under certain conditions problems can happen like mentioned in the above posts. Take it for what its worth.

 

[chrisk1500]

You may need a new hose to run from the crossover to the pump...I needed a new one but I can't remember if it was because of the crossover or the pump.....

 

[kimagine]

The 130gph waterpump impeller is over 1/4" larger in diameter than the 85gal impeller - NAPA carries the identical brand as oem GM, so you can compare the pumps there - look for an HO or HD on the upper front housing, or compare impeller sizes, '95 to '98.

Should be seperate part numbers for standard '94-95-96 maybe '97, and for sure HO '98

All bolt up, the same.

GM, what about the 93?
My radiator is new/er. Maybe a couple of years now(I lose track of time so easily now ). T-stat is newer since I've gone through several of them due to the very cold reading of my truck unless I'm on the highway and it reads between 180-190, but never over.

Mark:beerchug:

 

[BigIron.45]

WooHooo
Finally done with the pump. What a pain in the ***! Got the old one out with no problems, found a diagram somewhere in here that showed the timing cover connection. Got a reman '97 pump at the local NAPA got it home and in the truck. total time on that about 1.5 hours. Started hooking things back up and noticed the new pump did not have a nipple for the bypass hose, went back to napa and destroyed the old one trying to get it out and then spent the next 8 hours chasing around town trying to find a 3/4" NPT- 1"ID hose fitting... They don't frigging exist around here ended up with a 1/2"NPT-1"ID hose in a 3/4"NPT-1/2"NPT bushing.

That all being done it seems to have worked though.
Thanks for all the help and advice!!!

 

[DavidPhillips]

Mine seems to be working great.

I am waiting on a thermostat housing to upgrade the crossover. I don't see any problem with the single for now.