Pix of TBH on my D1 currently being tinkered with for head gaskets. You'll note that the heater cavity circulates coolant to warm the bottom of the throttle body, which prevents ice up of the butterfly valve. Has no easily measured value for mpg, etc. It is possible to put the gasket on backwards, this might not be easily seen without a mirror if doing the repair with throttle body still attached to intake.

If reversed, there would not be good flow. Of course, after cleanup, new gasket, I blew thru the hose port to be sure, and was rewarded with a whistle from the new leak.....

Pix of old, new correct line up, wrong line up, and leak. Time for new parts.

 

If its not one thing, Thanks for the write up.This weekend I was helping a friend with
a 99 Ford Ranger engine and for a split second thought wow glad I have a Disco.I am sure that may change this week.

 

To be honest, i just remove my TB heater. I live in Texas and the last thing I need is more heat on my air intake.

 

At $189 for one from Rovers North that idea is looking better and better. The D2 ones are like $25....

 

Mine was bypassed with a piece of fuel line by the PO....maybe 3" long from one port to the other. I replaced the expansion tank plastic lines also with 5/16 fuel line.

 

Well, you don't need to bypass the hoses that fit on the device (that is closing off the two fittings from the device, nothing in there), you need to bypass the hose from the intake (hot liquid supply) and run it to the radiator (return to tiny hose bib near battery).

 

Yeah, I was wondering why they would cap both the ports on the throttle body....I didnt think there was any reason, but wasnt sure..
On mine small intake manifold bleed line runs to the expansion tank, and the small radiator bleed line runs to expansion tank...seems to work fine