Temp Gauge reads hot rad temp only 175???

[184baller]

Ok my truck has been running 3/4 or higher . Ive done new water pump, Thermo, sending unit. I have 2 electric fans . Rad stays cold to the touch on the drivers side and hot on the passenger side. I bought an aftermarket temp gauge and put the sensor in the fill spout it reads about 175 but the dash gauge reads 3/4?

 

[SVTmountianeer]

have u changed the radiator ! it sounds like a clogged radiator

 

[184baller]

thats what i was thinking .

 

[184baller]

has any one had a temp gauge go wrong, i know the previous owner changed the gauges. the truck seems to start at almost half (normal temp) then climb from there. when i ground the gauge (wire attached to sender) it goes of the chart .

 

[184baller]

nerer mind it tested ok so far

 

[184baller]

does any one know the amps from sending unit to gauge at normal operating temp?

 

[Maniak]

I think you mean voltage.. as its measuring voltage difference between ground and a ref voltage to figure the temp.

When we rebuilt the motor we changed the temp sending unit. With the new unit 195F reads about the M in normal which is hotter than it read with the old motor/sending unit combo.

Once we rebuilt the motor I was really worried that things were running hot. I spend a few weeks driving and then checking the temp of the upper radiator hose and thermostat outlet using an infared temp sensor. It always seemed to be reading about 185-195. I finally put in an aftermarket water temp sensor. I installed in in the heater hose from the head (the hot side) and thats when I found that the new gauge was showing 195 when my infared showed 195 but the factory gauge was showing hot.

Just something to think about..

 

[184baller]

yea sorry the voltage cause it should change as the temp does right? so you had the same problem as im having?

 

[Maniak]

Yes, our factory gauge reads high even when things aren't hot. I verified things by installing an after market gauge and put the sendor in the hot heater hose (from head).. I also used an infared temp sensor to make sure the after market gauge and the water temp were the same by checking the radiator hose and the thermostat housing.

~Mark

 

[184baller]

how did you install the new gauge in the hose? is it a mechanical or electric gauge?

 

[Maniak]

I used an ISSPro water temp gauge. They are a 270 degree (sweep) gauge that uses an amplifier and a 2 wire sending unit. This means you don't have to ground the sending unit. I installed it in the heater hose (the hotter one) since there is always hot water going through there, even when the thermostat is closed. This will show me the temp of the water coming out of the engine.

I used an adapter like this...

This is the gauge I used (This is where I got it from too).
http://www.egauges.com/vdo_ind.asp?Type=Elec_Engine_Temp&Series=EVM&PN=R6750

I did find that at dusk it is a little hard to read the numbers..

This pic is for the trans temp (and has red pointers, which I also have installed) so you can see what they come with (water temp and trans temp both have the same style parts).

~Mark

 

[184baller]

has anyone else had to chane out there temp gauge or install an aftermarket gauge?

 

[Afboy143]

I used an ISSPro water temp gauge. They are a 270 degree (sweep) gauge that uses an amplifier and a 2 wire sending unit. This means you don't have to ground the sending unit. I installed it in the heater hose (the hotter one) since there is always hot water going through there, even when the thermostat is closed. This will show me the temp of the water coming out of the engine.

I used an adapter like this...

This is the gauge I used (This is where I got it from too).
http://www.egauges.com/vdo_ind.asp?Type=Elec_Engine_Temp&Series=EVM&PN=R6750

I did find that at dusk it is a little hard to read the numbers..

This pic is for the trans temp (and has red pointers, which I also have installed) so you can see what they come with (water temp and trans temp both have the same style parts).

~Mark

Im intested in using this adapter on my secondary transmission filter kit so I can monitor the temps. Where did you get it?

 

[Maniak]

The 5/8" heater hose adapter I got from a local speed shop. I paid I "think" $25. I have also made one of those using a threaded galvanized coupler with hose fittings on each end and a hole drilled/tapped into it. We did that on a friends f-150.. It cost us $5 to build.

For the transmission, we have our sending unit in the pan. It sounds like you want to put it on a transmission filter kit. If your filter mount doesn't have a place to install the sender you "might" be able to drill/tap the filter mount. Or go to a decent hardware store and get 3 pieces of brass. 2 of them are hose barb (the size to fit your rubber transmission line) to threaded pieces and the 3rd is brass block with threaded holes on 3 sides. One hole is for the sender, the other 2 are for the hose adapters.

~Mark

 

[184baller]

so any ways it was a faulty gauge and I went to pick a part got a new clusterand the temp reads cold. all i gotta do now is ajust my electric fan and back in busness .
my advice is if you have a temp problem check coolant level is it 50/50 mix, then rad cap , thermostat , temp sending unit .thats all cheap. if thats not it then maybe get it tested to see what the computer temp is reading.