I have a old coolant temp gage setup I want to put tn my truck. Where is the best place to put the sending unit? I'm not sure where there is a coolant plug? Thanks

 

There is a removable plug on the water pump below the t-stat housing. I think that would be an ideal place. In the photo, the plug is visible in the triangle space bounded by the upper radiator hose and serpentine belt (below the alternator but above the lower hose extension tube...)

 

I put my sender in the plug Greg shows. Had to get a couple of adapters from Ace hardware to make it work.

 

Another look at the same location.

 

I have a coolant filter hose coming out there. Would it be ok to put it in an open port on the coolant filter head? Not sure that would be too accurate?

 

Put a tee in the hose. At full operating temp and pressure you will get an accurate reading.

 

I have mine in the coolant filter head. Best I can tell is they are within a few degrees of each other. When I installed it, I checked the surface temp at the water neck and the surface temp at the coolant filter and found the coolant filter was a couple degrees cooler. When I installed the gauge, it reads right what the IR gun reads.

 

Ken, what temp are you seeing with it mounted there?
I just want it close enough to know that the thermostat is operating properly.

 

I run a 189 degree t-stat. I usually see 180 degrees on my gauge. The IR Laser Temp gun show about 185 on the t-stat housing and 180-183 on the filter head.

 

Holy crapola, whatever happened to the "recommended" 203* stat?

 

The 203* T-Stat is not for everyone. It got a ton of hype which sold lots of them. I use my truck to tow mostly and the oil temp climbs with the engine temp. I like to keep my oil below 200* so I run the OEM T-Stat.

 

Thanks for the replays and pictures. I am gona use the idea of the port on the coolant filter as above. Nice easy location. Will see tomorrow how well it works. Thanks again.

 

Pictures of members posting up where they installed there sensor at, is where i installed the line for the coolant filter. I took BDRummonds idea/pics, and "stacked" the oem sensor with brass fittings, and then installed my sensor there....(see pic in my "coolant" album).