Heater By-Passing...Your Thoughts

[mrnickleye]

I was thinking (usually too much), and am always anal-izing everything, so what about this......

The coolant flows out the back of the head and goes to the heater control valve. When the valve is open (always except when the A/C is set to 65*) the coolant flows thru the heater core, then on to the water pump intake side.

So...if the A/C is set to 65*, and coolant is stopped from "flowing", does this increase the heat on the rear of the head???????

My VSV for the auto operation of my heater coolant valve is missing, so I have always just put the vacuum hose to the valve to get heater operation.
In the summer I have always unplugged the vacuum hose and capped it off, so the A/C would be a few degrees cooler (no hot water in the heater core).

Now I wonder if I should leave the coolant flowing to the heater core to help keep the head cooler.?????

Also...my head gasket, and many others people's I've read here about, blew around the #6 cyl. Perhaps this is the "hot spot" problem in these heads.

[ddmcse]

here's my thoughts
i recently by-passed the whole heater setup. my heater core is/was leaking .
i have a fluidyne radiator and a 160 degree thermostat and now i can't get the engine temp to get anywhere near 190 , it barely gets to 160 . i might need to change the thermosat to a normal temp.
i go right from the center of the back of the head to the block intake side .
i used to depend on the heater core circulation to take that extra 10 degrees off the engine temp but now i see that it's much cooler by-passing , after years i am finally at a point where i need to get the engine warmer instead of worrying how to cool it off.
i am looking forward to some really hot summer days

[mrnickleye]

Yea, by-passing the core will keep the coolant flowing, but I am wondering if just stopping the flow by shutting off the heater coolant valve will create more heat at back of head.
Or if the block/head ports are enough to do the job. I wonder if the Toyota engineers were "counting" on the coolant flow thru the core to help keep it cooler.

I think I'll just keep the heater coolant flowing to insure more cooling.

Also, I've had good success with a 180* thermostat. My temp never gets over about 1/3 on the gage (unlees I'm pulling a mtn grade with the a/c on, in summer). Its 15* cooler than original, but warm enough to keep the sensors happy, and the heater hot.