Wrong waterpump?? - Diesel Forum

dmscranks · 03-03-2005, 03:22 PM

I bought a waterpump for my truck from napa and it looks the same the onl difference i can tell is the lower part of the pump is bolted on versus on my old waterpump it is a one piece unit. I installed the pump on the motor an bolted it up everthing went to gether the same and i test drove it just enought to warm it up to make sure there were no leaks and there are non and i parked it. I also used the same t-stat. Did i get the wrong pump?

Thanks Chris

Griz · 03-03-2005, 03:39 PM

No...It sounds like you have a newer (1996 and up) style water pump. Make sure you have using a long shaft thermostat. The 1995 water pumps come with a shorter shaft thermostat. I am using the newer style on my 1995 with a dieselsite 203-degree thermostat and it seems to work fine. [img]/ubbthreads/images/graemlins/phoney.gif[/img]

dmscranks · 03-03-2005, 03:45 PM

What will happen if i use the t-stat out of other water pump in the new one?

Paul H · 03-03-2005, 04:16 PM

If you use lets say a 95 thermostat in a new style pump, then the stat will not work right. the bottom end is too short to be in the flow from the bypass. The new style pumps have the lower outlet is bolted on.

If you use a newer thermostat from a 96 on up in a 96 pump the bottom is too long and will close off the bypass all together and the neck may not seal.

dmscranks · 03-03-2005, 06:20 PM

So how do i tell if i have the correct t-sta in the pump now? I do have the pump with the lower unit bolted on it was supposed to be for a 1995 truck as i had to special order it. Is there a way to measure if i have the short one or not? Should i go back to napa and have them research the part number on the pump i got and have them give me the correct t-stat?

Thanks Chris

Griz · 03-03-2005, 07:26 PM

Chris you can either go back to Napa and have them research what they gave you or remove the thermostat and measure the distance from the seat to bottom of the thermostat well. You should be able to tell from that whether or not you have the right thermostat [img]/ubbthreads/images/graemlins/phoney.gif[/img]

TimC63 · 03-03-2005, 08:55 PM

Hey Chris!

The round disc on the bottom of the stat moves downward when the stat opens and the disc has a round seat below it in the casting that you can see when looking into the stat's opening.
You can judge how far that disc moves down (by looking at the stat) and whether determine if it would seat on the casting when open. The difference in height is significant, so as stated above, it should be obvious whether or not you have the right stat!

My $0.02!

God Bless,

TC

AlH · 03-04-2005, 04:43 AM

[ QUOTE ]
The new style pumps have the lower outlet is bolted on.

[/ QUOTE ]

Not necessarily----I have a 96 and my OEM pump is one piece and so was the replacement from International. I also have a 95 pump on hand that is one piece. They do take different thermostats as well as different heater hose fittings from 95 to 96. 95 is pipe thread and 96 is 0-ring sealed.

ALD · 03-04-2005, 07:41 AM

This is a picture of the 96-97 style pump. water pump I replaced 2 last year, 1 had the bolt-on lower and 1 was cast. Notice the bypass port inside the t-stat housing. The short t-stat won't reach from the t-stat seat to the bypass - also, I think the short t-stat doesn't have the disc on the bottom to close off the bypass port.

DeiselDaddio · 03-04-2005, 02:51 PM

i just want to say thanks for all you powerstroke people on this site [img]/ubbthreads/images/graemlins/biggrin.gif[/img] i read this post last nite at work and found out the long and short of it if you catch my drift i have new 95.5 and later pump and a 95-95.5 t-stat just put rad and new houses etc. expensive coolant 2 days ago. found out about this last nite [img]/ubbthreads/images/graemlins/eek.gif[/img] the good thing is i found out before trouble hit.evidently the fellow that sold me the truck didnt know either thanks again [img]/ubbthreads/images/graemlins/warmsmile.gif[/img] kirk