Heater hose routing.

[Smokinthehippies]

Hey guys
So current heater hose routing on my rig has one port in the intake, and one in the water pump housing. So what they did was block off the port in the radiator with a rubber plug. Although it looks like they did it about 20 years ago. So while wheeling this weekend it sprung a leak and was pissing coolant.
So I want to plug one of the hoses coming out of the block and go back to using the radiator.

Just not sure which one I need to plug. The intake or or water pump port.

Any advice is always appreciated.

 

[blazer74]

The one in the water pump is the return, manifold is supply. water pump or radiator for return. Either will work.

 

[Avery4jc]

The one in the water pump is the return, manifold is supply. water pump or radiator for return. Either will work.

Yep and if you plumb it like I did with only the water pump and radiator and no manifold you'll only get mediocre heat and that's after everything is 100% warmed up on a not so cold day.

 

[Smokinthehippies]

Perfect that's exactly what I thought but I couldn't remember. What I need to do is come up with a shut off for the summer.

 

[diesel4me]

A simple ball valve from Home Depot or Lowes will work fine for a shut off..had two on my '72 Blazer when I plumbed up a rear heater for it that I got from a school bus,that way I could shut off the heat in summer,plus prevent coolant loss in the event one of the long hoses leaked...

 

[Smokinthehippies]

Is there any issue as far as flow or trapping air with just blocking off both ports? Just leaving the whole thing closed off for now? I can't really control the heater bcuz the control box is busted and there's no levers left to adjust, so it makes up its own mind about being hot or not.
Almost thinking just leave it out of the loop for the next few months and if it starts getting chilly just plug the hoses back in.

 

[diesel4me]

I've by-passed leaky heater cores by joining the two hoses together with a 5/8 x 3/4" coupling many times on GM vehicles,I dont see why corking off the outlets on the engine and pump with pipe plugs would act any differently..I wonder what GM did factory on southern cars and trucks with no factory heater?..

Most vehicles with A/C that have a hot water shut off valve only blocks off one hose to the heater,so I guess its not nessasary to block off both hoses...

 

[dyeager535]

Hmm. Hadn't thought about it prior, but on the factory setup, the heater core serves as a thermostat bypass...it keeps coolant moving, which theoretically even on a cold motor is probably important. But as mentioned, there were SOME applications without heaters, so did GM still run a hose from the intake to the radiator, or simply eliminate the extra hoses completely.

It's my understanding that GM realized there was an issue with coolant flow towards the rear cylinders, and I know one solution was that on some applications the rear coolant ports were tied together, and in others, like the early 90's Suburbans (no idea about others) the heater pressure feed came out of the rear of the intake, which would help coolant circulation there. So it would seem to me that GM felt it important on some applications to make sure coolant was always moving, even with a closed thermostat.

I know on the Olds motors (at least in the 80's) a heater valve was on the pressure side of the heater feed, but those motors have a bypass off the thermostat housing to the water pump already. I don't know if the small block Chev motor powered cars of the same period used a valve. Maybe some did, I'm not real familiar with vehicles like the Caprice's and Corvettes in that regard, but I don't believe the Monte's were setup with one. Whether that was an "upscale" brand difference vs. cost savings vs. functional difference in the motor cooling, I'm not certain.

Even if the reasoning for no valve on the trucks WAS for a cooling concern, in reality I'm betting the difference is so small that almost no one would have an issue due to it. Heck, it could even have been an emissions deal, where combustion byproducts were variable due to different cylinders having different operating temps.

 

[blazer74]

Connect the two together or run a hose from intake to rad. Bypass relieves pressure in the block until thermostat opens. Generally if u have a heater shut off u have a bypass of some sort.

 

[Smokinthehippies]

Well I just got new hoses and clamps and went intake to heater to radiator. I tried putting some ball valves in but the fittings leaked so I just put em direct onto the nipples. Ill try to find a better valve tonight and approach that idea again later. But for the moment I'm back in the saddle.