Donald Mitchell
1990 C1500 5.7L
Will adding a heater control valve help the A/C work better?
Keeping interior cool
- Thread starter Donald Mitchell
- Start date
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east302
I'm Awesome
My two-door Tahoe has one (pickups did not). It’s vacuum operated from a solenoid valve on the firewall and a line from the PCV fitting.
It’s not the most scientific and it’s by memory, but when I checked it a couple years ago my vent temps were about two to four degrees cooler in the Tahoe with that valve closed. But, it has a bigger cabin than my truck (ex-cab) so the truck cools down a little faster.
Neither are much to write home about compared to modern systems, but I don’t see a lot of value in the valve with mine. Rear air would have been a much better solution had GM chosen to spend the coin.
Splicing a valve into each line would probably have the same effect. Quality window tint helps as well.
It’s not the most scientific and it’s by memory, but when I checked it a couple years ago my vent temps were about two to four degrees cooler in the Tahoe with that valve closed. But, it has a bigger cabin than my truck (ex-cab) so the truck cools down a little faster.
Neither are much to write home about compared to modern systems, but I don’t see a lot of value in the valve with mine. Rear air would have been a much better solution had GM chosen to spend the coin.
Splicing a valve into each line would probably have the same effect. Quality window tint helps as well.
454cid
Sooper Pooper
It should, but I have no idea how evident it will be. I have a ball valve that I plan on installing in my truck, at some point. 200F coolant isn't doing any good circulating through the cab in the summer. Mine will be manual, since my truck didn't originally have one, there's no way that I know of to make it automatic. I think the vehicles that did have them had an electronic to vacuum relay type thing that then activated the valve.
The ball valve I have is a plumbing part, and will dead head the heater circuit, but it shouldn't do any harm since there is a separate thermostat bypass to keep the engine cooling stable. I think the valve GM used in the 400's was a bypass style, but the one in my Buick was a vacuum operated deadhead.
It's mainly an SUV thing, although Rockauto lists one for my truck, it never had it.
Donald Mitchell
1990 C1500 5.7L
Thanks, I was looking at an electric one and I'm pretty sure I could make it work. a lot of the older cars had them and got me to thinking.
L31MaxExpress
I'm Awesome
Even the ones GM put on do not fully close. I put a manual ball valve on mine. It is closed about 9 months out of the year here.
If your ac is not working well it is not the era of truck. I have been in a family of this generation of trucks, suvs and vans since they were new. My uncle had a 97 ECSB and my aunt had a 98 Yukon that they had since they were new back in the day, long since sold them. The 97 Express has been around since 98. My brother and I have had no less than 7 Tahoes, Yukons, Suburbans and Trucks. The 99 Suburban and 99 Tahoe we kept for several years would both freeze you out of them. If the ac is not cold it most likely has a leak or airflow across the condenser issue. If the ac is blowing weak the evaporator is clogged with crap or the blower motor is weak. The foam seals at the duct work also degrade over time and leak the air out behind the dash. Wrap the joints in the ducts with aluminum tape. My van and Tahoe will both blow your hat off with cold air.
If your ac is not working well it is not the era of truck. I have been in a family of this generation of trucks, suvs and vans since they were new. My uncle had a 97 ECSB and my aunt had a 98 Yukon that they had since they were new back in the day, long since sold them. The 97 Express has been around since 98. My brother and I have had no less than 7 Tahoes, Yukons, Suburbans and Trucks. The 99 Suburban and 99 Tahoe we kept for several years would both freeze you out of them. If the ac is not cold it most likely has a leak or airflow across the condenser issue. If the ac is blowing weak the evaporator is clogged with crap or the blower motor is weak. The foam seals at the duct work also degrade over time and leak the air out behind the dash. Wrap the joints in the ducts with aluminum tape. My van and Tahoe will both blow your hat off with cold air.
Cadillac Bob
Slammin original 4x4 Cadillac doors!
My 400 Escalade has rear air small separate system for only the rear I wished it was a dual system that supplied heat but it’s only ac
Donald Mitchell
1990 C1500 5.7L
No my system is all new and I havent had it charged yet. I was just wondering if anyone else had done this to their pickup and if it worked well .
L31MaxExpress
I'm Awesome
Yes they have worked well on everything I have put them on.No my system is all new and I havent had it charged yet. I was just wondering if anyone else had done this to their pickup and if it worked well .
I used a pec valve on my super duty, worked great.
Have you ever ran a blue orface tube?
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