Mazda temp gauge, overheating, temp sending unit issues....

Truck is a 87 B2000 w/ original motor that was rebuilt about 30k miles ago. It is bodied and bagged. Motor has a pacesetter header, weber carb, and electric fans.

The gauge reads hot, real hot. On my way to Dropzone it was pegged all the way to the H but was runnin great.

I don't doubt the motor runs hot but just how hot is the question.

If I start it and let it idle within a couple minutes its 3/4 of the way up the gauge and by the time I hit the end of my driveway its most the way up.

We've installed a new water pump, thermostat, temp sending unit, and even tried another identical tach gauge cluster.

With the temp sending unit wire unplugged and testing the resistance at the sending unit I have no reading. As the truck warms up the resistance drops to about 20.9 ohms where it pretty much stays. At an idle it never drops more than that.

Now here is where I'm not sure how things should act. With the key off I can test resistance at the temp gauge wire at the sending unit with it unplugged and its about 100 ohms. If I unplug the gauges I get no reading on the wire.

The electric fan is moving more than enough air and I believe the radiator to be in good working order. I don't believe the truck is overheating but I really want the gauge to work properly just in case.

Does anyone know what the ohm reading of the sending unit should be at running temp?

I'm gonna buy a laser temp gun so I can test the temps and see whats goin on.

lol i just posted over there for him to go with after market mechanical guages the stock guages i dont trust.......

if not tell him to replace the sending unit they arent worth two shitsss

i would go over and post to put a new sending unit in but i only have 2 more posts for the month on streetsource...lol

If you read my original post you'll see that I've already replaced the sending unit.

And I don't want to run aftermarket gauges. Keepin the truck clean inside and out.

kewl

flow test the radiator, my yota did that cept it was actually getting hot, engines run more effecient when hotter, just other components cant handle the heat and which is why the break down shortly there after easiest way to tell if it were REALLY getting hot, if your gas mileage went up like 3 miles per galloon while driving it hot. if it stayed the same then lemme know and we shall go a different route. good luck man.

U didnt say anything about replacing the thermostat.Use a two stage Mazda thermo-1st stage opens at 160,second stage opens at 180.When installing be sure and put the tiny air bleed hole at the 12 oclock position.BJ

Bump.Also be sure u have the correct radiator cap.BJ

New thermostat and new radiator cap. Bleed hole is at 12 o'clock.