Keeping interior cool

[454cid]

Yes its different. Its keyboard duster, canned air.

I thought that was r134a, too..... had it been, at one time?

 

[L31MaxExpress]

I thought that was r134a, too..... had it been, at one time?

If it ever was R134a, it has not been in more than 10 years. The use R152a because the GWP is much lower. I remember both R12 and R134a used for portable marine horns though.

 

[MIHELA]

With as brutal as this summer has been so far I've been thinking about getting the AC sorted on my truck. I need lines made and need to make sure the A6 will work in this application. I have already swapped the superheat switch to a pressure switch style.

 

[1998_K1500_Sub]

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

Splicing a valve into each line would probably have the same effect.

The OE water valve's design is such that, when activated, it shunts the coolant flow back to the engine, bypassing the heater core... it doesn't simply "shut it off". As such the OE water valve maintains the coolant flow in the heater coolant circuit, but shuts the flow before it reaches the heater core, returning it to the engine / water pump.

See it here:
HEATER VALVE
GM GENUINE 155533

More Information for GM GENUINE 155533

As noted, one could put valves in the lines. But...

I though it is required to maintain the coolant flow in the heater circuit of the SBC engine (not "deadhead" as was mentioned earlier). I swear I read that, somewhere. Perhaps the Vortec SBC engines are different b/c they have the bypass from the intake manifold to the pump. (Yes, SBC engines with non-Vortec heads AFAIK have a bypass from the right-side cylinder head, though the block, to the water pump, but it seems like a rather restrictive path).

Pontiac in the 70s used a deadhead coolant shut-off valve in the heater circuit, but that's a different engine.

 

[1998_K1500_Sub]

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

Now that's bizarre... a Cadillac GMT400 with only rear air and no rear heat.

I would expect the Caddy to include all typical options as std equipment.

I learn something new every day.

 

[HotWheelsBurban]

Now that's bizarre... a Cadillac GMT400 with only rear air and no rear heat.

I would expect the Caddy to include all typical options as std equipment.

I learn something new every day.

No rear heat...in a Michigan truck? OMG!

 

[east302]

The OE water valve's design is such that, when activated, it shunts the coolant flow back to the engine, bypassing the heater core... it doesn't simply "shut it off". As such the OE water valve maintains the coolant flow in the heater coolant circuit, but shuts the flow before it reaches the heater core, returning it to the engine / water pump.

See it here:
HEATER VALVE
GM GENUINE 155533

More Information for GM GENUINE 155533

As noted, one could put valves in the lines. But...

I though it is required to maintain the coolant flow in the heater circuit of the SBC engine (not "deadhead" as was mentioned earlier). I swear I read that, somewhere. Perhaps the Vortec SBC engines are different b/c they have the bypass from the intake manifold to the pump. (Yes, SBC engines with non-Vortec heads AFAIK have a bypass from the right-side cylinder head, though the block, to the water pump, but it seems like a rather restrictive path).

Pontiac in the 70s used a deadhead coolant shut-off valve in the heater circuit, but that's a different engine.

That is a good point about maintaining circulation. A crossover and third valve would then be in order to keep the loop function.

 

[Donald Mitchell]

Its basically a pressure sensitive orifice tube that changes the size of the opening in response to pressure.

Can you give a part number? I looked them up on Napa and it shows several.

 

[L31MaxExpress]

The OE water valve's design is such that, when activated, it shunts the coolant flow back to the engine, bypassing the heater core... it doesn't simply "shut it off". As such the OE water valve maintains the coolant flow in the heater coolant circuit, but shuts the flow before it reaches the heater core, returning it to the engine / water pump.

See it here:
HEATER VALVE
GM GENUINE 155533

More Information for GM GENUINE 155533

As noted, one could put valves in the lines. But...

I though it is required to maintain the coolant flow in the heater circuit of the SBC engine (not "deadhead" as was mentioned earlier). I swear I read that, somewhere. Perhaps the Vortec SBC engines are different b/c they have the bypass from the intake manifold to the pump. (Yes, SBC engines with non-Vortec heads AFAIK have a bypass from the right-side cylinder head, though the block, to the water pump, but it seems like a rather restrictive path).

Pontiac in the 70s used a deadhead coolant shut-off valve in the heater circuit, but that's a different engine.

Definately not necessary. Industrial applications typically do not have a heater. My old 83 G20 was built with a valve that was a simple dead headed block off as were almost everything until the late 80s/early 90s.

 

[L31MaxExpress]

Now that's bizarre... a Cadillac GMT400 with only rear air and no rear heat.

I would expect the Caddy to include all typical options as std equipment.

I learn something new every day.

The Tahoe body length required its own rear unit design. Its shorter than the GM box with rear heat.