Help me understand a heater pipe delete

THE BULL · 07-27-2022, 10:21 PM

Hello everyone.

As these engines get swapped more often I would like to explore some of the options to "simplify" the cooling system. Already running a TB coolant bypass.

My questions came about the heater pipe bypass. I've seen some folks bypass the heater by running a hose from the engine's heater outlet to inlet.

It appears like in these engines the heater is usually seeing flow (certain cars bring a flow valve to stop coolant flow through the heater). It seems like anything 2000 + Nissan/Infiniti does not.

I'm sure the vent doors block airflow, however the heater must allow a few degrees of cooling it still sees hot coolant being sent back into the Tstat area.

With that being said, the Tstat already receives a hot feed for opening already from the back neck.

I have the heater pipes capped and so far can report normal function however makes me question if a bypass over capping would offer any benefits in cooling or such?

My theory is the heater pipe by the T Stat shares the channel of the second hose. By bypassing the heater you're sending hotter than the return coolant back into the bottom of the block. Wouldn't capping be more efficient?

Excuse my ignorance if it has been covered before.

THE BULL · 08-02-2022, 12:31 PM

Seem like my theory was correct. Bypassing the heater and not capping the pipes will send hot coolant to the bottom part of the block to blend with colder coolant.

In the oem configuration, having the heater will lead to a cooler effect even if there is no air flow going through it

As you can see the inside cavity of the thermostat where the hoses go are only divided by a small piece of aluminum, this is so the heater change in temp doesnt affect thermostat operation. These cars do not bring a heater flow valve meaning coolant is constantly running through the core and it's the blend doors job to block airflow so you dont get hot air.

Time will tell however I wonder for those experiencing high coolant temps while racing if they'll see a significant improvement in coolant temps by shutting flow to the heater all together.

07-27-2022, 10:21 PM	#1 (permalink)
THE BULL Base Member Join Date: Apr 2021 Location: Florida Posts: 217 Drives: G37S Rep Power: 26848	Help me understand a heater pipe delete Hello everyone. As these engines get swapped more often I would like to explore some of the options to "simplify" the cooling system. Already running a TB coolant bypass. My questions came about the heater pipe bypass. I've seen some folks bypass the heater by running a hose from the engine's heater outlet to inlet. It appears like in these engines the heater is usually seeing flow (certain cars bring a flow valve to stop coolant flow through the heater). It seems like anything 2000 + Nissan/Infiniti does not. I'm sure the vent doors block airflow, however the heater must allow a few degrees of cooling it still sees hot coolant being sent back into the Tstat area. With that being said, the Tstat already receives a hot feed for opening already from the back neck. I have the heater pipes capped and so far can report normal function however makes me question if a bypass over capping would offer any benefits in cooling or such? My theory is the heater pipe by the T Stat shares the channel of the second hose. By bypassing the heater you're sending hotter than the return coolant back into the bottom of the block. Wouldn't capping be more efficient? Excuse my ignorance if it has been covered before.

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08-02-2022, 12:31 PM	#2 (permalink)
THE BULL Base Member Join Date: Apr 2021 Location: Florida Posts: 217 Drives: G37S Rep Power: 26848	Seem like my theory was correct. Bypassing the heater and not capping the pipes will send hot coolant to the bottom part of the block to blend with colder coolant. In the oem configuration, having the heater will lead to a cooler effect even if there is no air flow going through it As you can see the inside cavity of the thermostat where the hoses go are only divided by a small piece of aluminum, this is so the heater change in temp doesnt affect thermostat operation. These cars do not bring a heater flow valve meaning coolant is constantly running through the core and it's the blend doors job to block airflow so you dont get hot air. Time will tell however I wonder for those experiencing high coolant temps while racing if they'll see a significant improvement in coolant temps by shutting flow to the heater all together.