Im brand new to this site so Im not really sure how this works. I have a 95 12 valve with 300,000 miles on it. On long steep runs pulling a 8,000 trailor, my eng. temp gets pretty warm, near 220 degreees. I try not to let my EGT's go above 1300 deg., so I usually run the hills at about 1200 degrees. When I got my truck, it had 250,000 miles on it and I instantly put in a #5 TST plate, im not sure if it ran hot or not before I put the plate in it. Is it most likely it overheats cause of the high mileage, or can the #5 plate be contributing to the overheating? I am not by any means easy on my truck, I run the living hell out of it. On the flats it runs fine, Ill pull 20,000 pound trailors around the farm no problem, but Im also not running very fast or pushing it hard with load like that. Any thoughts would be greatly appreciated.
first place is the check the thermastat and coolant condition. i dotn have any 12 valve experience, but the plate adds more fuel, so could add more heat. you watch your EGT's so you should be good there. just a thought i guess.. Grant
Yep, Id check the thermostat out first. Also take a look at the fins in your radiator to see if many of them are plugged up with dirt/road debris/bugs the usual garbage. 300k miles is alot of time on the road. Next, check your fan clutch operation, if it doesnt engage when the temp starts to climb your coolant temps will continue to rise when they should level off. What temps does the truck run at around town?
Like already mentioned change the thermostat and make sure the radiator is clean. On your truck you have the older copper/brass type radiator and I'm not familiar with them in the 12v's much myself. If the radiator is clean and a new stat doesn't help I'd pull the radiator and have it rodded out, or just replaced.
Thanks for the response guys, really appreciate it. Ive replaced the thermostate and fan clutch already and it helpled a little bit. The radiator isnt in great shape after I looked real hard at it, so Im guessing thats probably the main cause. Thanks again.
Is the truck an automatic? If so, you're probably pulling grades with the torque converter unlocked which builds tremendous heat that gets dumped into the cooling system through the radiator tank tranny cooler. If it's a 5 speed, ignore the above and rework/replace the radiator. Rusty
Please spend some time rereading the forum. It is impossible for a Cummins to have any trouble at all pulling a grade. It is simply impossible.
I have been reading this post and can't believe that no one is seeing the #5 plate and the 1200 - 1300 degree temps? this is what is heating your rig up? Bring your EGT's down with a turbo charger upgrade, intake and exhaust upgrades or a smaller plate, more air equals less EGT's which equals lower engine temps. Check out my signature, I have pretty much the same rig, and when I put our Super-B turbo charger on it, I brought my EGT's down from 1200 to 1000 degrees, problem solved! Eliminate the source of the heat, there is no point of having all that fuel/HP if you can not use it. Hope this helps.
So what your saying is that a #5 at 1200deg is gonna cause 220 temps pulling a hill. Well I should see 330degs then with a 210pump #10, 370's, 3gsk's and a HK35/40. Not to be an "A" hole but when I'm pullin' 1200deg I never see 200deg or anything over 2500rpm
CumminzRig can you hear your fan clutch engauge. The stock fan is pretty loud and you'll know when it comes on. Pull the radiator and have it cleaned by a radiator shop. It probably has deposits on the tubes inside and restricting flow. Other than that do the obvious and the change coolant (for red) an the thermostat because it's cheap. Hows the fan belt. There is a little arrow on the belt tensioner to let you know it's limit but you've gotta look for it.
