What did you do with your GMT400 today...or yesterday....

[Big T]

yeah that hose is a pain. I cut the old one in half to make removal easy.

Right now while doing it is the time to add the restriction fitting. For ease Leroy sells his wazoo one. Enjoy pinching pennies on trucks so you can spend it on the ranch instead means diy one. Nate’s example in his build thread is a simple and effective method.
My method was weld it up with a brass rod 3/8” diameter for the hole. The method GM showed as popular was welding a new one, slow cool so it wouldn’t be hardened, drill 3/8 hole then reheat it and quench for temper. Of course they described exactly how they felt customers would do it and if we saw the part done this way to leave the customer modified part in there and simply note it in the vehicle history. Then for some reason when installing the new part they were available as a “-M” part number and we got paid an extra 1.2 hours for some unknown reason, they never would admit that this is what you are supposed to do.
Gotta love the lawyers.

It’s got the single stat crossover and the HO water pump with spin on fan clutch.

I cut the hose about an inch longer than the one I took out, then two more cuts to properly size. Flipped the worm screw clamp so the screws are on the passenger side pointed forward for better access in the future. Foamed the front of the engine and impacted areas underneath with purple degreaser shot from pressure washer, let soak and rinse with pressure washer. Then I filled the coolant reservoir with new coolant mix and went for a 5 mile test drive. Test drive showed appropriate cooling and no coolant leak.

 

[Will L.]

@Big T single stat with block off, right?
If so cool- no restriction fitting needed

 

[dbrannon79]

Remind me again which style needs the restriction fitting? the single with the block-off t-stat or the newer dual stat crossover?

 

[Big T]

Remind me again which style needs the restriction fitting? the single with the block-off t-stat or the newer dual stat crossover?

I run the ‘99 with dual 190 t-stat crossover, HO Pump, spin on fan clutch and Dmax fan. It barely ever gets over 187 and mostly stays at 185.

 

[Will L.]

Remind me again which style needs the restriction fitting? the single with the block-off t-stat or the newer dual stat crossover?

The dual thermostat is the one that needs the restriction fitting.
The problem with the dual thermostat not having block off capability is there is a constant flow of already fully heated water going back into the block and heads limiting the amount of cooling that can be done.
With @Big T suburban staying where it is (especially if measuring the rear of the passenger head) then it should be left alone.