Second function of heater hoses?

PeterAllen · #1 (**permalink**) 10-27-2015, 06:19 PM

I am about to connect hoses from the LS1 to the heater (Vintage Air). I was familiar with the system which simply placed a tap in the inflow hose and opened and closed depending on how much heat was required in the cabin. That is the style of tap which came with the Vintage Air kit.

The tap from the VZ Ute donor car creates a system whereby water is constantly flowing through the hoses and the heater is something of an additional take-off loop. I was lost as to why this level of complexity.

Feedback from other forums suggest the heater hoses also carry water used to cool specific areas of the engine, e.g. cylinder heads, where the water cavity flow doesn't effectively cool. It doesn't matter whether the water has previously passed through a cabin heater or not.

Because the heater ports are part of the pump on an LS1 I'm trying to find out why the LS1s have this constant flow arrange and if it would be detrimental to convert it to the simpler inflow restriction method? Thanks.

Here are images of the VZ heater tap and water flow:

Gav · #2 (**permalink**) 10-27-2015, 06:33 PM

The system takes water from the engine side of the water pump to allow for a faster heat up of the cabin heating on cold starts.
As for cooling the heads etc, I'm not so sure if that.

PeterAllen · #3 (**permalink**) 10-27-2015, 07:32 PM

Quote:

Originally Posted by Gav

The system takes water from the engine side of the water pump to allow for a faster heat up of the cabin heating on cold starts...

Thanks. I would have thought it would be a fairly marginal gain?

Quote:

Originally Posted by Gav

...
As for cooling the heads etc, I'm not so sure if that.

That comment related to other motors, not an LSx.

Gav · #4 (**permalink**) 10-27-2015, 08:00 PM

Older systems have to wait for the thermostat to open before they receive any heat.

stephen low · #5 (**permalink**) 10-27-2015, 08:26 PM

Possibly like the AU Windsor set up requiring some margin of constant flow past one of the sensors to properly trigger signals to the ECU through all temperature ranges.

This was what I was told and so I made up an "H" type fitting in front of the heater tap inlet-outlet to facilitate proper engine operation as well as heater capability.

Rebel1 · #6 (**permalink**) 10-27-2015, 10:16 PM

Have a read of here:
Pirate4x4.Com - The largest off roading and 4x4 website in the world.
Scroll down to the heading "LS Cooling system" about 1/3 down the page.
It's a very extensive explanation of the GM cooling system.

Paintwerks · #7 (**permalink**) 10-28-2015, 12:39 AM

Although I haven't been able to start my car yet, I have fitted a heater to my Absolute Pace and I'm running an LSA. Based on the advice I was given by a DRB owner who is running a similar setup, there is no need to run a valve to control the amount of 'heat'.

He said that there's no need to stop the heat in the cabin because when the fan is off, there is no heat coming out of the unit.

07cob · #8 (**permalink**) 10-28-2015, 02:48 AM

Peter

Not a LS (302W) but similar situation. I have a heater unit under the dash and originally thought it would be a good idea to put a simple ball valve in to keep heat out of the cabin. I tried this after the first summer running the car and it immediately got very hot with the valve closed. Opened the valve and all was well again. Figured that the cooling required the circulation and stopped worrying about it.

Regards

Geof

guye · #9 (**permalink**) 10-28-2015, 05:05 AM

Had a related debate around my LS2 and removing the heater altogether. Do you block of the heater inlet/outlets or loop them? There are many peeps that have done either, and no one really reports any issues.

However my personal opinion (just logic-based and not mechanical-engineering-degree-based) was to install a loop. This is because as it bypasses the thermostat, i reckoned it would probably get the heated water to the thermostat more thoroughly and quickly, thereby opening the thermostat when it was expected to. Also the back pressure on the thermostat would be less.

I don't see (on my engine anyhow) that heater line doing anything else other than the interior heater, by the way.

Anyway, I'll shut up now, and als refer you to that Pirate4x4 site rebel1 mentioned. It is the ducks nuts! I've used that for so much info during my build it's not funny!

Aussie Mike · #10 (**permalink**) 10-28-2015, 05:20 PM

I have blocked mine off but drilled a bypass hole inside the housing to let coolant circulate.

gjkrv8 · #11 (**permalink**) 10-28-2015, 05:52 PM

I have had my Heater outlets on my LS1 blocked off for 7 years and no probs on road in heavy/hot traffic or on track. Cheers Gregg

Modena · #12 (**permalink**) 10-28-2015, 07:09 PM

I have them looped.

Jaydee · #13 (**permalink**) 10-28-2015, 10:09 PM

Usually the bypass is internal, and then closed of by the disc at the bottom of the thermostat. So if you remove the thermostat it'll overheat, as most of the coolant will flow through the bypass passage. I'm not sure if later engines have these.
JD

CHANMADD · #14 (**permalink**) 10-29-2015, 10:50 AM

I would think that .......firstly .the constant flow would enable heating to commence quicker as the flow is already there. Also, the flow would prevent a hot spot and subsequent steam pockets from forming.
Nothing to with pressure.