Heater Core bypass

Roustabout

Active member
Mar 27, 2010
28
0
Ontario, Canada
Has anyone successfully installed a heater core bypass valve something like this:
http://www.thermotion.com/pdf/4_Port_Data_Sheet.pdf
A3pV4O01+J2bAAAAAElFTkSuQmCC


I've always hated the idea of hot coolant constantly flowing through the heater core and relying on a plastic flap to keep the hot air separated from the cold air. During the hot months I'd like to be able to isolate the heater core from the cooling circuit.

If anyone has done something like this, did they see any appreciable difference in engine operating temperature?
 

KyleT

Well-known member
Mar 28, 2007
6,059
8
36
Fort Worth, TEXAS
no need. not really any benefit. i have run bypassed in a pinch when the hose blew out. no difference in anything.

it will cause the auto temp to just blow full cold all the time.

if you are having problems running hot, there is something wrong.
 

Roustabout

Active member
Mar 27, 2010
28
0
Ontario, Canada
Hey Kyle

My rig runs pretty cool: 188(highway)-197(idle) in 90 deg weather with the
PEL500110 thermostat. I'm just trying to improve cabin cooling efficiency. I notice if I set the climate control to Economy the air coming through the vents seems quite a bit warmer than the outside ambient temperature(worse on the passenger side).
 

KyleT

Well-known member
Mar 28, 2007
6,059
8
36
Fort Worth, TEXAS
yeah my guess is the hot exhaust/engine bay air does more for that than the heater core. in econ the heater core is blocked off to airflow still if the temp or whatever is set low.
 
Aug 20, 2007
2,673
28
Nashville TN
I did when my heater core blew. just loop the two coolant pipes on the passenger side of the engine that go into the firewall. you'll do the loop right around the back of the valve cover. plug up the two exposed pipes so they don't get contaminated until you fix it. I just used some coolant hose and hose clamps. make sure it doesn't kink when you loop them.

as for a valve, haven't done it, but don't see why it wouldn't be possible.
 

pdxrovermech

Well-known member
Jul 3, 2009
1,779
49
Portland, OR
I have shut off valves in my custom rig. Makes a big difference, but only because its a homemade heater box that air still passes through even without the fan on.