Temp gauge????

[B-train]

Typically a thermostat will overshoot on the first opening cycle, but then settles in. Does it take awhile of driving for this to happen, or is it all the time? I've seen air pockets mess with the temp sensors in the past - they usually read low, then blast up when the coolant hits it after its been heated hotter than normal due to being trapped with an air cushion.

I'm with those above that stated air in the system. Have you let it idle when hot with the reservoir cap off? This usually aids in getting air out. I also massage the upper hose when running to encourage air bubbles to move upstream. If it acts normal with the cap off while running, then raises/acts weird when it gets pressurized, you could have a head gasket allowing a small amount of compression (air) into the system, which will cause erratic issues. I mention this because you said the upper hose blew off before replacing it.

Another point is the radiator. Is it OEM, or aftermarket? Guys here have mentioned things in the past about an orifice that is too big on aftermarket ones that causes cooling issues. I'm sure others can chime in, I personally haven't had to deal with it.

An IR gun is a good way to get a baseline of temps when it's running. Check the delta between upper and lower hoses. Then reference heater hoses as a comparison.

 

[OriginOfKaos]

Typically a thermostat will overshoot on the first opening cycle, but then settles in. Does it take awhile of driving for this to happen, or is it all the time? I've seen air pockets mess with the temp sensors in the past - they usually read low, then blast up when the coolant hits it after its been heated hotter than normal due to being trapped with an air cushion.

I'm with those above that stated air in the system. Have you let it idle when hot with the reservoir cap off? This usually aids in getting air out. I also massage the upper hose when running to encourage air bubbles to move upstream. If it acts normal with the cap off while running, then raises/acts weird when it gets pressurized, you could have a head gasket allowing a small amount of compression (air) into the system, which will cause erratic issues. I mention this because you said the upper hose blew off before replacing it.

Another point is the radiator. Is it OEM, or aftermarket? Guys here have mentioned things in the past about an orifice that is too big on aftermarket ones that causes cooling issues. I'm sure others can chime in, I personally haven't had to deal with it.

An IR gun is a good way to get a baseline of temps when it's running. Check the delta between upper and lower hoses. Then reference heater hoses as a comparison.

Thanks for your response. I just did another bleed. I turned on the heat and i let it idle. The tstat did open up at about 210. The upper hose got hot, bubbles came through my radiator funnel and the coolant level lowered. I did try to squeeze any air out of the upper hose.

This time, i let it idle for at another 10 mins or longer to make sure all the air was out. I got zero bubbles but the needle kept going up and down slowly. Never passed rhe 210 mark. Im letting it cool of now. i topped of the coolant tank as well. The radiator was one from NAPA. Thats what the guy told me.

The needle moves with or without the cap on. Now, i noticed that when i turn the vehicle off, the needle shoots to the 260 mark. Never seen thay before. i assume the engine cools off when you turn it off so i dont know why the needle does that.

I do not have a IR gun. Guess i should invest in one.

 

[Hoesgottaeat2]

And yes, it is normal to see a rising temp after shut off. I've heard that phenomenon called "heat soak". The coolant in the block is no longer being circulated to the radiator where it's heat can be more quickly wicked away. Also the accumulated heat rises to the top as heat does...and the temp sensor is right at the top of it all.

 

[OriginOfKaos]

And yes, it is normal to see a rising temp after shut off. I've heard that phenomenon called "heat soak". The coolant in the block is no longer being circulated to the radiator where it's heat can be more quickly wicked away. Also the accumulated heat rises to the top as heat does...and the temp sensor is right at the top of it all.

Ok. Thats good to know! You guys rock! I am thankful for all of the help! My last option is the temp sensor. After that, i may have to just drop it off at a shop. Thankfully, there is one honest where i live.

 

[Eman85]

You do know that those "gauges" are indicators and after 20+ years they are less than accurate.

 

[east302]

It would be worthwhile to get a scanner on it to see what the coolant temperature (ECT) sensor is reporting to see if you’re just chasing a gauge or cluster issue. That sensor is the one by the thermostat and is what the computer uses.

The one on the lower driver side is the one that controls the cluster needle. It’s called the coolant temperature sender (versus sensor) or something like that.

There’s probably a way to ground the sender connection and test the gauge, but I’ve never looked into it.

 

[OriginOfKaos]

It would be worthwhile to get a scanner on it to see what the coolant temperature (ECT) sensor is reporting to see if you’re just chasing a gauge or cluster issue. That sensor is the one by the thermostat and is what the computer uses.

It would be worthwhile to get a scanner on it to see what the coolant temperature (ECT) sensor is reporting to see if you’re just chasing a gauge or cluster issue. That sensor is the one by the thermostat and is what the computer uses.

The one on the lower driver side is the one that controls the cluster needle. It’s called the coolant temperature sender (versus sensor) or something like that.

There’s probably a way to ground the sender connection and test the gauge, but I’ve never looked into it.

The one on the lower driver side is the one that controls the cluster needle. It’s called the coolant temperature sender (versus sensor) or something like that.

There’s probably a way to ground the sender connection and test the gauge, but I’ve never looked into i

OK! Thanks. Not sure where to get a scanner tool. Ill google that. I have no cel. Ill look into the sender unit as well.

 

[Hoesgottaeat2]

OK! Thanks. Not sure where to get a scanner tool. Ill google that. I have no cel. Ill look into the sender unit as well.

In the meantime until you purchase a scan tool you can always stop by your local Autozone or Advanced Auto they will scan your truck and give you a print out free of charge.

 

[OriginOfKaos]

In the meantime until you purchase a scan tool you can always stop by your local Autozone or Advanced Auto they will scan your truck and give you a print out free of charge.

Looks like i will be doing that today!! Now that i think about it, i have no cel. So it couldnt be the sensor right? I would like to assume that if the sensor is bad, i would have a cel??

 

[Hoesgottaeat2]

Looks like i will be doing that today!! Now that i think about it, i have no cel. So it couldnt be the sensor right? I would like to assume that if the sensor is bad, i would have a cel??

A bad sensor may or may not throw a CEL in my experience. Depends on how it's failing. Go get it scanned to verify the temp is somewhat accurate first. One step at a time man.