The Stovebolt Site Forums The Shop Area Engine Shop Water Temp Gauge

Hey guys, not sure if my original water temp gauge is working or not, it pegs to 212 pretty quick while idling. Can I install a mechanical gauge where the petcock in the block is just to see if the original gauge is working or not?

Thanks in advance!

Forgive my ignorance, but what's a "mechanical gauge"? Are you talking a bi-metallic meat thermometer? I don't think it will pick up the heat sufficiently, and has a pretty coarse resolution.

I have no idea what year stovebolt you have, but mine isn't graduated to temp values. It is either pegged low, at some sweep inside of the range, or pegged high. Mine tends to run fairly close to mid-range, dependent of course on the ambient temps and how much idling I'm doing.

Have you considered taking off the radiator cap, starting the engine and running at idle until reaching stable temp, then using a kitchen thermometer (electronic barbecue tongs with LED readout) to read the temp inside the radiator through the neck? It isn't the exact same as where your temp sending unit is probably located, but it is closer to the thermostat and can be a benchmark.

Are you running a 50/50 blend of coolant/water?

What temp is your thermostat?

Have you confirmed operation of the thermostat with a stovetop test?

Bill

An infrared thermometer is handy as pockets on a shirt.

what year of truck?

what model/ton rating?

what engine/tranny combination?

-W

1949 chevy half ton 3100 216 3 speed

New water pump, new 3 core aluminum radiator, 180 thermostat, all new belts and hoses

There is a petcock valve on the drivers side of the engine that I am guessing you can use to drain coolant from the engine. Can that petcock valve be removed and a water temperature gauge hooked up there?

Thanks, hope this extra infor helps

there isn't enough depth behind that fitting to insert a sender, if you want to do something like that you need to use the same location your regular gauge sender is installed [which should already be a mechanical one], but as suggested a good laser digital termometer will do the job to determine if the gauge is accurate

with everything new as you list, I'd suspect the gauge or an air lock at the thermostat, did you drill the small hole on the thermostat flange as usually suggested?

Bill

Biil, can you explain the small hole thing to a newbie? I have a similar problem. Thanks

Peter - you can chack for water flow when the temp climbs by looking in the top of the rad .... sometimes on the first use air gets trapped under the thermostat so that the temp isn't transferred to the stat button by water contact and it doesn't open - if you drill a small hole in the flange beside the flap it allows that air to be pushed past the stat so the water contacts the whole thing to properly heat it up to opening temp

Bill

how does the temp sender line disconnect from the back of the gauge under the dash? 53 3600

Drilled the hole before I put the thermostat in.

Wasn't sure if there was enough depth for the gauge where the petcock in the block is. Thanks for answering. Not sure about the gauge yet but my new aluminum rad leaks in 4 places. Ugh!

It doesn't. It is a sealed unit.

The line, bulb, and gauge are filled with some sort of liquid. If any part of the gauge assembly leaks, or gets damaged, the whole thing is shot and will need replaced. The good news is, most of the vender's sell and repair gauges. You can buy a cheap-o aftermarket gauge and use the same fittings in the block for a quick test. As for getting air out of the system. Drill a 1/8" air hole in the flange of the thermostat or place a aspirin in the thermostat as you hold it open with your fingers. Once coolant fills the system the pill will dissolve away. You will never get the t-stat to open with out coolant touching it, hot air or even steam will not do it.

Joe

Why not warm the truck up, and stick a meat thermometer in the top of the rad, where the top hose dumps in?

The temp gauge on my truck is graduated, but not accurate. What it thinks is 180, is really 160. My Pontiac is worse, what it thinks is 200, is really 160. I've driven that car over mountain passes at 100 degrees outside, and it doesn't overheat same with the truck. The gauge just shows relative temperatures, not accurate ones.

As long as the coolant coming out of the top hose and entering the radiator is the same temperature as your thermostat, there isn't much to worry about.

I'd measure the "real" temperature before worrying.

Thanks to all
More good stuff to know!