heater control valve
 

Driving my 93 3vze today noticed all the sudden the truck was blowing cold air instead of heat. Get out open the hood steam antifreeze smell hit me right in the face. the intake into the hcv had broke off in the hose. i ended up having to get a nipple and bypass the hcv. Will this in anyway hurt the truck to leave it like this for a few days or should i park it until the new hcv comes in? i still have heat somehow and the temp guage is reading normal.

Can't imagine any harmful effect of bypassing the HCV.

i wouldnt think so, but the odd thing is even with the hcv bypassed i am still able to adjust the level of heat coming into the cab. Any idea of why? what exactly is the purpose of the hcv?

There could be a damper that is changing position letting in more or less outside cool or inside recirculated air thus giving some temperature control. When you bypassed the HCV, you plumbed it so coolant is still going thru the heater core, correct?

thats true, i just put a nipple connecting the hoses on both sides of the hcv, therefore bypassing it. Not a permanent fix, but just wanted to make sure that there would be no negative effects from doing so.thanks for the replys too.

There is a difference between the truck and 4Runner airflow paths, The pickup airbox will bypass the heater core as well as the HCV when the temp lever is adjusted.
(I just looked at the one I have sitting on the side of the house to be junked, I installed a 4Runner Heat/AC into my truck because of the larger heater/AC cores and there easyer find, I likes my heat.)

I've been running with the HCV bypassed since May 2011. The only thing I noticed is increased vent temps when the fan is off. The HCV cuts coolant flow through the heater core when the temp is set to cold to keep heat from building up in the case and increasing the cold temperature. You will only notice it during hot days if you don't use your AC.