I'm trying to increase the cooling of my A/C. This truck doesn't use a water valve but blend doors instead to separate heat from cool. There still is a fair amount of heat given off by the heater core when the temp dial is set to cold, you can even feel it in the center console lower storage pocket.

I'm looking to install a water valve to cancel the hot water flow to the core. As you know there are two heater core hoses going through the firewall. Facing the engine the hose entering on the right comes off a flange fitting on top of the engine and the one entering on the left is connected to the pipe that is o-ringed connected to the back of the water pump. As well each heater connection to the hoses has a by-pass that diverts some hot water to the throttle body - which I don't want to interrupt.

It appears that flow direction is from the flange fitting to the core, out of the core and to the pipe that fits into the back of the water pump.

I would prefer to install the water valve on the inlet to the core (right side hose), but that hose is behind the hose that outflows water from the core and therefore not accessible. It looks like I can use a water valve on the outflow flow from the core and still not interfere with flow to the throttle valve.

Are my findings and assumptions correct? Does anyone see any possible problems? Thanks.

It seems to me that if the water valve is in the heater core outlet; the water flow will still be stopped.Some of the other guys here may know if stopping the water flow there would cause any other adverse effects;but I don't see how it would cause any problems.Good luck & stay cool.

I have a feeling you're going to get somebody saying there IS a water valve on there. I haven't bought into that myself, as I've not taken one apart to see.

In any case, I did this years ago to an infamously bad Chevy product that debuted in 1976 (O.K., it was a Chevette), and it worked beautifully. Can't remember which hose was used, though. The car wasn't equipped with a/c, and it made a huge difference during warmer months.

Good luck and keep us posted.

John B.

This is a really good idea and I shall be stealing it for my own usage. I don't see any reason why it shouldn't work the way you describe. And I looked thru ASA and I don't find any valve of any sort.

Yes, my own FSM did not show any existing water valve. My Ford Ranger has a neat vacuum operated one that I want to emulate as I don't want to run a mechanical cable through the firewall or use an electrically operated one - just not into doing the wiring on this project. I could just use a mechanically operated one (without cable hookup) and turn it by hand twice per year.

By the way a 3/4" connection is what mine is as I have an existing Prestone coolant flush adapter in there now. It's to NAPA next week to see what they have as the last I remember they have a good selection of OEM water valves to choose from.

Look at this one. It's of the manual, twice a year variety, but I've not had to warranty any of them for leaking. I sell a buttload of them to the forklift/lift-truck maintenance & repair companies in town. At the website you should be able to enter your zip code to see if your local NAPA store has one in stock.

Thanks for the link. That looks to be the easiest and cheapest install and most trouble free option. I just need to determine if the offset connection will work with the hose. I'll let you know.

Yep - It won't make a bit of difference which hose the valve is installed on - You won't get any hot coolant flowing into the passenger compartment either way.

I used an ordinary ball valve and a couple of hose barbs from Home Depot on my 2.6 - but then again, there's quite a bit of room to work with on that engine.

I dont know about the 92 and up but the 91 has a valve in the metal line that connects to the heater core. It moves with the air temp control.

My Haynes manual shows a heater valve on earlier models (88 and back) located under the dash at the heater core but none on later versions. I made a call to the dealer and the parts guy cannot find a valve for my year. I'm pretty sure there is not one.