Beater79TA

Factory heater lines on a 3rd gen go through a plastic flow control valve located near the AC compressor. A vacuum hard line from the firewall goes to this valve to divert hot water through the heater core when vacuum is applied to the valve by the climate control switch inside the car. This vacuum hardline is part of the bundle of wires located next to the AC box on the firewall near the centerline of the car. A hose from this valve goes to a tee in the metal hardline on the frame rail where the line goes to the radiator. Another hose goes from the valve to the firewall and heater core. The return line from the heater core does a 90 degree down the firewall to a hardline that wraps down the frame rail towards the front of the car.

The manifold vacuum lines go to a rubber line into the interior for the climate controls with a T fitting and check valve to a vacuum ball under the drivers side battery tray. The other line goes to the brake booster. What you did will work. Depending on the climate where you live, you might not even notice the difference. I live in AZ so I plumbed in the heater control valve to keep the heater core as cool as possible while running the AC.

No4Play

That's how it's ran...? I changed nothing from how the a/c and heat was set up from the factor when the car was purchased new in 91. It's a 2 owner car, my fiances and prior to that, her fathers. Still not sure what you're getting at.

STREETDEMON

your pictures of the engine bay show the heater core hoses going straight from the water pump. there should be a valve controlled by vacuum in the middle to divert the flow as beater stated, that's how it was delivered from the general.

more info in jbenge's swap thready down below...

https://www.thirdgen.org/forums/ltx-...s1-swap-2.html

scooter

iTrader: (11)

There is a coolant bypass on the 305, you can see it in the pictures in your thread

This

You did NOT connect it like factory on the 305, none of the coolant bypass stuff is in there. You have the heater lines connected directly to the water pump. If you're getting cold AC, then something is wrong because you shouldn't be getting cold air out of the vents like you have it.

I'm just trying to help.

No4Play

You guys are absolutely correct my fault for not realizing what the heck yall were talking about. But in all honestly the A/C does blow cold...?? Now that I have the old heater control valve in hand how the heck do install it?

drduster

iTrader: (2)

There are several ways members here have plumbed in the valve. Some used the original valve & others an aftermarket piece. My TPI car had a steel tube mounted on the frame rail for the hoses. I see in your pictures at the beginning of the thread that your TBI car has it too. I re-mounted it as close to the inner fender as possible to give more header clearance. I turned the heater bypass valve upside down, so the hose that would have gone to throttle body on the TPI was now facing toward the inner fender.

I used all the stock TPI hoses except those that went to the water pump: "heater core to steel pipe" (Dayco 88353), "heater core to heater bypass valve" (Dayco 87701) & "steel pipe to heater bypass valve" (Goodyear 4347). Then found molded hoses that were the right sizes & cut them to fit for the "heater bypass valve to water pump" (Dayco 87695) & "steel pipe to water pump" (Gates 28478). I bought some hoses from local part stores & ordered some from Rock Auto. They have good pictures on their web site.

Flip 2

iTrader: (1)

Just put to top….I did this…one of many of us who have…

https://www.thirdgen.org/forums/ltx-...-valve-ls.html