Hey Guys,
I have a 94' k2500 vin F. Water temps are a little on the warm side when pulling my trailer uphill. So I'm gonna try to switch it over to the dual thermostat setup. If I buy the newer 130 gpm water pump from the auto parts store, will it just bolt directly on to my 94' block, no problems?

 

Dual thermostats might not be the answer, how old is the current thermostat? and is it an AC DELCO? also an easier fix may be to do the Duramax fan upgrade someone may chime in but you will have to change a few things besides the thermostat housing.

 

When was last time the radiator and AC condenser external fins were "deep cleaned"

Between the 2 is a negative pressure area that accumulates a LOT of crud that packs in between fins and restricts airflow, remove radiator, get some foaming AC core fin cleaner concentrate from AC repair/supply house mix up in a bug/garden sprayer spray and let soak also spray AC condenser

BEE CARE FULL if it gets on paint it can hurt it, AC condenser can remain in place /connected for this just watch paint

Use garden hose and low pressure fan spray on nozzle so you don't damage the fins they are tight together and easily bent....myself when I do it I like to use my hotwater heater drain connection so I have hot water wash/rinse and also gets crud from bottom of the hot water heater....

To correctly do this takes about 3 hours or so the first time, you are flushing years of crud from the rad, wash rinse repeat until the junk stops coming out...same thing for the AC condenser.

 

Yeah, I put the new ac-delco thermostat in first thing but it didn't change anything. I'll clean the radiator and condenser. I already bought a used dual thermostat housing off ebay, wish I would have posted first. Oh well, is there any advantage to it?

 

Ok, so I had some time today to start gettn into it. You can see the bottom of the radiator is pretty clogged up. The truck also has an extra trans cooler inline with the radiator one. It's behind the grill in the second pic. I'd like to remove this, what do you guys think? I've always hated those through the radiator zip fasteners. There was also alot of crud sittn in the radiator mount tray zone.

 

I have extra trans cooler mounted under my bed with electric fan rated for 25K# cooling load similar to this one Derale Performance Electra-Cool Remote Fluid Coolers 15820 - Free Shipping on Orders Over $99 at Summit Racing , as you have correctly surmised the 6.5s "cooling stack" is already "at-risk" for any additional airflow restrictions from aftermarket add ons.

Factory oil and trans coolers go in front of the radiator one left is trans, and one on right is oil when looking from front to back each is about the size of a big tablet PC, I'd scrap the aftermarket zip tied one and go with a new oil cooler from Leroy Diesel leroydiesel.com/ with some upgraded stainless oil cooler line (OEM lines are bad design), and the Derale under bed option.

In grille coolers need fwd airflow what do you do in traffic when towing stop/go, the fan under bed insures trans is being cooled even when stopped, my fan with the optional electric temp switch turns on fan at >170F return temp to trans.

How does this help coolant/engine temp you might ask ??? well trans side of your radiator gets its cooling from engine coolant so less heat load from the trans = less heat overall the radiator has to manage/deal with.