Have many TPI owners done this mod? I am in process of tearing down the top of the motor for various reasons, and read that someone else got rid of the valve. I was think of just running a hose from the lower intake manifold directly back to the heater core. Then pull the valve and one other hose, blocking off the lower fitting on the metal hose. You could just splice the 2 hoses togethor where the valve was, but a new hose would look better.

I think I understand why GM did this, but what about the coolant that is NOT flowing thru the heater, as in when the temp lever is in full cold? It just lays there, possible creating rust and corrosion? My shop manual shows 2 different views of a TPI motor, with and without the heater valve. So I guess it can be done. What TPI cars did not have this valve?

Now for another question, if coolant is continuously flowing thru the heater core, does this mean I will get heat in the passenger compartment, even when I have the lever in "cold"?
One more dumb question, sorry. What direction does coolant actually flow? I'm guessing from the lower intake manifold, to the valve, to the heater core, then back to the radiator? Seems like you would take hot coolant from the motor thru the core, then back to radiator to cool down. Plus don't forget that engine oil cooler that is also hooked up.

Just want to get some discussion going, thanks!

 

I know my friend's '88 vette doesn't have one. Maybe thats the picture that you saw. I havn't looked close enough at it to see how the hoses were routed though.

 

When you have your temp set to full cold, the valve bypasses the heater core to the other hose you see running down to the metal pipe.

If you bypass the valve, and plug the other hose, you will have a constant flow system. Not a bad thing.....

There is a "temp door" inside the heater box that actually regulates the temp. Having the constant flow thru the heater core will reduce the effectiveness of your A/C (provided you have it) but, prolly not noticeably.

I have no clue what GM had in mind with that valve. It is normally open, and when you put the temp lever to full cold, it applies vacuum to put the valve in the "bypass" postion.

You are correct on flow direction.

 

I understand that earlier years did not have it even.
I am going to remove mine, one to get it out of the way, and two, the 'T' joint below the A/C box has a very small (but annoying) leak.

Cheers

Richard

 

Thanks for your replies, folks. I checked my service manual again, and it shows a nice diagram of how the airflow goes thru the heater core. The temp control lever basically regulates how much air goes thru the heater. In full cold, it blocks outside air thru the core, and in full hot, lets all air go thru the core. So I am not worried that I will get heat when I am in cold postion.

I just need to find a piece of coolant hose with a 90deg end, to run from the lower intake outlet, all the way back to the heater core inlet. I don't want to make any splices if possible. Then I will just pull the vac line out from the valve, and plug it off. I will likely leave the metal T fitting in the lower hose, and maybe just use that for flushing purposes.

I do have AC, but don't use it that much. I had it serviced one summer, thought maybe I had a leak. The dealer found nothing wrong, but gave it a new shot of refrigerant. Helped some, but still don't get icy cold!!