obscurotron

To go along with my oil pressure and tranny temp gauges that I just finished up on my V6 Tacoma (I have a spare space in my 3 gauge pod) I want to install a *real* coolant temp gauge. Should be simple enough, right?

Most folks say "tap a heater hose". Fine. Except - hot coolant only flows through the heater hose when the heat in the cab is turned *on*, correct? I even noticed Gadget did this on one of his trucks. Wouldn't that make that an very inaccurate location for the temperature probe? Does the heater control valve include a small bypass to allow minimal coolant circulation? Am I missing something here?

My only other thoughts were to either splice into a TB coolant line (tiny fittings, not sounding like fun to work with) or the upper radiator hose. I prefer to do whichever is the least amount of work, and the heater hoses are convenient, so the wiring run will be pretty short. Clues?

Thanks

obscurotron

Btt...

phorunninduke

The best spot to tap a hose would be right between the thermostat and the radiator. It has the biggest and shortest hose and thats where the hottest water should be.

As far as I think...

dstrick32

I drilled and tapped my upper inlet connection on my 3.0!!

obscurotron

I don't even know what you're talking about. The 3.0 and the 3.4 are pretty different engines in terms of layout, hose routing, etc.

phorunninduke

yeah, but ALL engines have thermostat and a radiator inlet. The inlet will be at the top of the radiator, the outlet at the bottom.

obscurotron

Just for the record, if some other poor hapless person comes along this thread looking for the same answers, the heater hose is a no go, and I don't want to cut my radiator hose.

My solution - home depot - 1 1/8 x 1/8 x 1/8" brass 'T' fitting and 2 1/4" barb x 1/8" NPT hose barb fittings. I'm going to splice that into the inbound throttle body coolant line and get my reading from there.

First benefit - no need to wait for the thermostat to open to get a reading. This should give me a reading right from the start as the coolant circulates in the head and block. 2nd benefit, if I have a leak, it's a 1/4" hose leaking, not a 1.25" hose leaking! 3rd benefit - plenty of good spots to ground the sender with a minimal wire run. 4th benefit - closer to the firewall for getting the sender wire inside the cab.