Ok, I just got done installing a new electric temp gauge and I put it in the side of the head. I moved my mechanical sensor up to the top of the manifold. Took it out for a spin yesterday and I am getting 2 completly different readings. The gauge with the electric sensor reads between 180-185 where the mechanical one is reading between 190 - 200. What gives?? I would really like to believe the electric one as it does not get the effect of ambient heat that the mechanical one does. Any clues??

Thanks.

Jeff,
I have not actually tried it, but I would think that the on one top would probably show a little hotter temp than the one in the head. It is the last point of travel before the water gets to the radiator. If you have an ir heat gun, "shoot" both spots and see if there is a difference.

Swap places with the gauges and see what happens and your concern over ambient temperatures affecting your gauge readings is unwarranted.
Mike

Mike,

Actually I HAD the mechianical one in the head, that is what started this whole thing. I would stop in traffic and the gauge would very quickly start to rise. So I bought the electric one and moved the mechanical one up to the manifold.

Thanks.

I got that but to find out if there reading correctly you need to move the electric one to the manifold and see what it reads,you will then have the information you need to determine whether the gauges are reading correctly and if you have a temperature difference in those two locations.
Mike

I would do what M.Maner suggested. If you still get the same readings, the gauges are probably reading right. If not, trust the more expensive gauge. ;)

Like BillK said, the temperature does vary, depending on where the sender is put. The coolant runs from the bottom and up, so I'm sure it's normal for a reading close to the thermostat housing (like in the intake manifold) to be higher than in the cylinder head. Don't know much about what the temperatures should be in different places, but the standard place to put the sender is in the cylinder head so that's what I would use for reference.

The temp in the heads and block are the most critical, not the temp in the thermostat housing. I'd configure my cooling system to measure and regulate the temp in the head to the spec I wanted and ignore the temp at the t-sat. It will be whatever it wants/needs to be. If you really want to drive yourself crazy, put a third sensor in the radiator. ;-)

i have mine in the head..........double checked the rad. temperature with a meat thermometer and they both read the same 180 deg. with a cheapo sunpro!

Ok, I will swap those around this weekend and see what comes up. Thanks for the help.