As some of you here know I have had a over cooling condition in my truck for quite a while. It seems to be getting worse. No matter what tstat i am using now the temp is hard pressed to get over 175 and will drop to 155 but seems to stay just below 170 most of the time. This is in 70 weather, in town or high way and with 2 of my winter fronts in place. I am on my 7th tstat with the same results. I even sent one of them to Mike and it runs fine for him. After 6 190* tstats and one cummins 180* tstat with almost the same results with them all I am at my wits end. I have also replaced the temp sender twice and no differance. I am wondering has anyone else here had this problem. Not long ago I replaced the heater core and refilled the engine thru the tstat hole and even put water in thru the heater supply and return. I cant beleieve there is any air in the block. The gauge will move between 155 and 175 but I cant get it any higher unles I am pulling the rv. But even then about 180 is the best I can seem to get.. I have noticed of late it the temp drops below 165 i get some EGT fluctuations and a little boost gauge fluctuations. If any body has had this problem I am very interested in hearing about them and any solutions you might have found.

First time I have read this issue, but the radiator is not your problem. If that was the case any of these trucks that drove empty on a -20° would never get warm. The thermostat will prevent the motor from running cold if you are making enough energy to warm the block (which you are). You more than likely have an indication issue. Based on the changes senders and dash I would say you have bad wiring, and your engine is more than likely operating normally.

LOL fire him anyway

I did, but the sob keeps coming back.

- - - Updated - - -

Drip,

Don`t want to derail your thread... but WTH could blow your radiator up like that???

I dont know if age was a factor or exactly how hot everything got. Last time I saw the gauge before it blew it was near 200 and climbing. I set and over temp code also. I dont know how hot it got, but she still runs the same. I took that same run a couple years ago and the temp went just over 200 and that tstat worked fine for a few months then went back to low readings again.

Are you towing with the winter fronts installed?

First time I have read this issue, but the radiator is not your problem. If that was the case any of these trucks that drove empty on a -20° would never get warm. The thermostat will prevent the motor from running cold if you are making enough energy to warm the block (which you are).

You more than likely have an indication issue. Based on the changes senders and dash I would say you have bad wiring, and your engine is more than likely operating normally.

I never thought the radiator was the problem, until I blew the end of of it. I blocked it off in the past just to see what would happen. It just made the fan came on. I agree with a wiring problem except when the gauge drops way down I can grab the top radiator hose and hold it with no problem. When gauge goes up to 165 it is to hot to hold onto. I know that is not very scientific but its all I got right now since I fried the mechanical gauge. I am going to pick up another soon.

- - - Updated - - -

Are you towing with the winter fronts installed?

I did have them on that day. The temp was around 40 that morning, got up near 50 for the rest of the day. No problem on the rest of the trip thru the mountains, other the gauge showing swings in temp of 25*(140 to 165). When the gauge was reading 165 the truck ran good, When it would drop down it would mess with gauges and the banks tuner. Like it was switching on and off .

Everything points to an indication issue, even the way you are holding the hoses. There is probably an electrical short somewhere, but your motor could be VERY hot when it indicates 200°, especially with winter fronts and towing. I may have missed it, but have you looked at the temp thru an OBDII scanner?After watching IAT's and coolant temps while towing with a winter front for testing I would suggest never running any winter front while towing, unless its -30° outside.

Everything points to an indication issue, even the way you are holding the hoses. There is probably an electrical short somewhere, but your motor could be VERY hot when it indicates 200°, especially with winter fronts and towing. I may have missed it, but have you looked at the temp thru an OBDII scanner? After watching IAT's and coolant temps while towing with a winter front for testing I would suggest never running any winter front while towing, unless its -30° outside.

I appreciate the info. I have not looked at it thru a scanner, but just bought a Scan Gauge II. It will be here tomorrow. Its time I put this one to bed. It has been going on long enough. If I do have a short somewhere, why am I seeing the temp swings like the tstat is opening and closing? It is a slow swing down and then back up. I would think a short would make it move quickly. The reaction I am getting from the Banks system is very much like a short but only occurs when the gets low enough. The cooler the worse the reaction.

I appreciate the info. I have not looked at it thru a scanner, but just bought a Scan Gauge II. It will be here tomorrow. Its time I put this one to bed. It has been going on long enough. If I do have a short somewhere, why am I seeing the temp swings like the tstat is opening and closing? It is a slow swing down and then back up. I would think a short would make it move quickly. The reaction I am getting from the Banks system is very much like a short but only occurs when the gets low enough. The cooler the worse the reaction.

I`m thinking the manual gauge should tell the true story. The temp fluxuations seem to indicate the thermostate is working properly in cold climate conditions.. the is when you say it continues even on warmer days. The Cummins engine seems to be a very cold natured engine to begin with.. I did a coolant flush a couple weeks ago and I did`nt think the thermo was ever going to open, and it was 70 degrees that afternoon

Okay folks, I now have the dash gauge, a mechanical gauge, and I installed a scan gauge II. I drove to work this morning. When i got there the dash said about 165*, the scan agreed with that. The mechanical gauge read 185* and I ohm'ed the sensor and it read 1.00. so it seems the sensor is reading good but the signal is degrading before it gets to the the electronic gauges. I do have a T-tap on the signal wire for my EB and maybe that has let some moisture into the harness. The only problem i my head was the over cooling problem predates the t-tap, though it has progressively worsened over time. So to all of you who have been telling me what i did not want to believe, thank-you, I now believe. MM needs an emoticon that has a very thick skull(insert here). Thanks to all who have offered advise and when I find the problem I will let yall know where it was. I am now ready for my:spank: .That is only one:spank: that i deserve and not 3.

no, you deserve 3. I told you a long time ago to stick a manual temp gauge on it..

lol

That appears to be an I told you so gauge, but it could double for a skull thickness gauge as well. Now if i can find a place to install on my dash.

Okay folks, I now have the dash gauge, a mechanical gauge, and I installed a scan gauge II. I drove to work this morning. When i got there the dash said about 165*, the scan agreed with that. The mechanical gauge read 185* and I ohm'ed the sensor and it read 1.00. so it seems the sensor is reading good but the signal is degrading before it gets to the the electronic gauges. I do have a T-tap on the signal wire for my EB and maybe that has let some moisture into the harness. The only problem i my head was the over cooling problem predates the t-tap, though it has progressively worsened over time.

So to all of you who have been telling me what i did not want to believe, thank-you, I now believe. MM needs an emoticon that has a very thick skull(insert here). Thanks to all who have offered advise and when I find the problem I will let yall know where it was. I am now ready for my

That is only one:spank: that i deserve and not 3.

LMAO!! where did you find that emoticon???

- - - Updated - - -

Okay folks, I now have the dash gauge, a mechanical gauge, and I installed a scan gauge II. I drove to work this morning. When i got there the dash said about 165*, the scan agreed with that. The mechanical gauge read 185* and I ohm'ed the sensor and it read 1.00. so it seems the sensor is reading good but the signal is degrading before it gets to the the electronic gauges. I do have a T-tap on the signal wire for my EB and maybe that has let some moisture into the harness. The only problem i my head was the over cooling problem predates the t-tap, though it has progressively worsened over time.

So to all of you who have been telling me what i did not want to believe, thank-you, I now believe. MM needs an emoticon that has a very thick skull(insert here). Thanks to all who have offered advise and when I find the problem I will let yall know where it was. I am now ready for my:spank: .

That is only one:spank: that i deserve and not 3.

This is probably an ignorant question ... but do readings such as temp, oil press, voltage pass through the PCM before registering on the dash gauges ??

click on "more" below the ones on the right and you will have all the you need. scroll almost to the bottom.The sensors read both thru the PCM and the ECM. Someone smater than me would have to tell which ones go thru which computer.

I know I am electronically slow but I just ohm'ed the sender as I was instructed to do(since MM pointed out the right way to do it). I have 1.2 ohms with the gauge reading just under 165*. Put in a mechanical gauge and it reads 200*, but during install my head mechanic seemed to let the capillary tube touch the + terminal on the battery and now it wont read below 140* no matter what. So I will have to get another gauge. I would fire the mechanic, but I am the only one I have.

If I may ask, what temp gauge are you buying again. I need to do the same thing on my truck.

El cheapo Sunpro from Advance. $17 auto zone has them too. I want to get the dash problem fixed so that gauge is reading right. The lead on it is not long enough to bring it in the cab unless you put a new whole in the fire wall. For now mine resides under the hood. I would go with the Isspro mechanical if I permanently install one however.