First off MERRY CHRISTMAS YALL, hope you get many fancy cummins parts under your tree!!


So I have a stock 2005 cummins Ram 3500 2x4 Dually 6speed mercedes 177k all maintence is done on time or early!

background
we had the fan catch the metal wire tube a few years back, we drove 1,500miles in mountains with a 45ft gooseneck trailer, heater on the whole way and after we got to north carolina a dealer put a new fan clutch and all in it, and still over heated some times

and it got a new radiator because it had "resticted flow" mabe 20,000 miles ago and it worked fine for a while

Problem
I can drive at 75mph all day and be at about 210 but if i touch the skinny pedal any more (2,500 rpms or higher) the tempurater gauge races for 245 and will stay there if i dont let off, if i let off the temp drops almost as fast back to 210!

Service history
truck is on radiator #2 with 20k miles And #2 OEM cummins water pump at 20k miles (original was perfect), fan clutch #2 over 50k miles, thermostat #20 something, collant should be correct dilution, and the radiator doesnt seem to lose fluid, atleast not recently, and cooling system has always been mostly corrosion free i think

before the original fan clutch burnt out, the truck would not move from 190 it didnt matter if you went 85mph towing in summer or if you went 5mph in winter, now the gauge will move faster then the speedo!

so my thought of course is run twin or triple electric fans and maby stick a REAL mechanical temp gauge because i never fully "trust" any computer controlled gauge, also maby free up those 26 ponies dodge had penned up

Any ideas, suggestions, or anything would be appreciated, thanks yall have a happy new year

 

Are you using the antifreeze that is called for. If I'm not mistaken it is called HOAT or something like that. I could only find it at the NAPA store when I changed out my water pump and AF.

 

thanks for the idea, can the wrong coolant (the any model, color, year, green stuff) make the engine spike 40 degrees in 30seconds because of 100 or 200 rpms and then drop 40 degrees in about 30 seconds when you let off?
andt te shop that did the radiator filled it, no idea what they used

its too predictably erratic for me to figure, if that makes anysense

 

Have you replaced the water pump? Seen the blades corrode off on other vehicles. When the engine is cold, pull the radiator cap. Do you have fluid all the way to the top of the cap or is it down a bit in the filler neck?

 

X2....
Also seen the the pump impeller slip on the shaft.

 

i forgot to add that the water pump was replaced at the same time the radiator was about 20k ago, and the stock pump was PERFECT but you know all the labor is getting to is so we did it, with the OEM Cummins Dodge from the dealer water pump not aftermarket
im going to check the coolant tommarrow when its light and hopefully dry, im also going to check the fan clutch wires
anything else i should check?
should i check for the small bubbles from a blown head gasket?
what if i put a 180 or maby a 170 thermostat in it, could that be a fix?
thanks

 

I wouldn't think a fan clutch would be an issue at that high of speed and rpms. I would check the head gasket department. You could check for bubbles in the coolant. but I wonder if you may be getting a leak when you are twisting it hard and at lower rpms its still holding together. If you are having coolant disappear or notice a lot of pressure in the radiator I would suspect that. It could also be a weak radiator cap. I would think though you would be having overflow issues to missing coolant. I had my old JD diesel tractor crack a head one time and had overheating and radiator pressure issues. Idling cold I could see bubbles purculating with the cap off. After repair I went on several test runs with it and had it overheat and pop the overflow. Double checked and rechecked everything in the head area and decided to buy a 5$ radiator cap and that took care of the problem. They say 2 lbs of pressure lost can increase 10 degrees in temperature.


Hows your serp belt doing? Twisting the engine that tight on rpms could be causing the water pump to simply slip and not provide maximum flow due to a poor belt or tension. I can beat on my old 74 Dodge with a 440 and get the belts to start slipping and the temp will go up in a hurry. Had the same issue with an old Chevy 6.2 I had. Highway driving somehow would loosen the belt and putzing around town it would squeal and slip.




47

 

Back to the coolant thing. I was told (maybe on this site) that if you mixed the two coolants, the stuff would become like jello. I've got no idea how you would check for that.

 

Yeap, check the belt tensioner. I have had a heck of a time getting air out of my system before after a fluid change. Loosen one of the plugs on the top of the head near the thermostat and fill until it runs out the plug hole. Air pockets can be a pain.

 

Sounds like head gasket is leaking, may want to have block check done. Does coolant boil over when cap is off and engine is revved up? If it does you have head gasket issue.

 

thanks for all the responses yall, the coolant is full it was a little down the filler neck but full, the shop that did the radiator had left a hose loose and one point and i did fix it and got all the air out at that time but there doesnt appear to be loosing enough coolant to be a leak, since its been several thousand miles since i checked it and then i checked yesterday

also this truck is on belt 8 and tensioner 3, the truck used to eat belts to shreds but it stopped a while ago, noone ever figured at why though.

what im going to try today hopefully is replace the temp sensor, check the cool, drain a quart and look for crudd, and also i bought some bug b gone spray and im going to clean my intercooler and ac condeser and all that, will also try to purge the air out of the system too, since im going to drain some

and if that doesnt work i think a mechanical temp gauge under the dash would be a good idea, because they dont lie

Also i was told Boric acid, i think, you can get it in roach pellets crush them and dissolve them and run water with it for 30mins in the system, and it will take the crudd out of the system, anyone heard of this or better yet done it?

 

I personally believe you have a transmission problem. It sounds as if your torque converter is slipping at lockup, when your temps start to rise around/above 2500 RPM. Does the tack rise slowly or does it fluctuate up and then fall back, a slipping transmission will cause higher than normal temps, Since you towed quite a distance with out a cooling fan. The radiator also cools the tranny fluid. Try these suggestions, may or may not help. Grant

 

transmision is perfect, maby the syncros arent and the clutch is worn but thats it, and rpms rise and fall steady just as steady as i tell them too, and the transmision is cooled from air under the truck its not connected to anything cooling related, thanks for the suggestion

 

OK i just check the serp belt and i can twist it 360 and pull it back about 2 1/2-3 inches, how much should the belt pull back/twist with how much force? it might be fine and im just mr. manly
maby the belt stretched or the tensioner is going...again, I do have a brand new belt hanging in the garage so i can check for stretch if i SHOULD, cause its a PITA
also i moved the truck (ran for 1 min) shut it down cold, and popped the rad cap and it spit coolant out, also i drained some and its the red/rusty color, but is not rusty i thinks its from the green and red coolant mixing
clutch fan wires are fine, and i pulled the condeser off and am cleaning it and the intercooler

also new temp sensor later, for gits and shiggles

 

Sorry my mistake assumed auto