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2018 ram 2500 6.4 cooling issues.

ClayG34

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My fans weren't working....at least not at the right time. I couldn't figure out what was causing it so I replaced the fan also I bought a unit from autocoolguy for my fan control so that I could easily monitor my fan operation. I know these trucks are designed to run with a 216° thermostat (damn) but its low 70's outside ambient temps and summers coming. My oil is hitting 222° range and thats during a 30 minute drive. My worry is I will have to haul a 30' bumper pull in a month or so. Please someone tell me something that makes me feel better about these temps. 220° oil temps under light driving is worrying me to death. Coolant temps since I've don the fan controller and new thermostat have yet to reach full operating temp (216°) that also worries me that the thermostat has yet to open.. any suggestions? Please brothers.
 
My fans weren't working....at least not at the right time. I couldn't figure out what was causing it so I replaced the fan also I bought a unit from autocoolguy for my fan control so that I could easily monitor my fan operation. I know these trucks are designed to run with a 216° thermostat (damn) but its low 70's outside ambient temps and summers coming. My oil is hitting 222° range and thats during a 30 minute drive. My worry is I will have to haul a 30' bumper pull in a month or so. Please someone tell me something that makes me feel better about these temps. 220° oil temps under light driving is worrying me to death. Coolant temps since I've don the fan controller and new thermostat have yet to reach full operating temp (216°) that also worries me that the thermostat has yet to open.. any suggestions? Please brothers.
I also drilled a 1/8" hole in the old thermostat and it worked great for a 30 minute drive but after it starts past 186° it keeps climbing. Now I have a dorman thermostat new and my fan controller is working perfectly. After driving a week with my new fan system I have only seen a high temp of 208°. I'm wondering if the fan system is keeping it so cool that the coolant is barely getting to temp and opening the thermostat, because it will hit 208° and start dropping to about 197° and then start the climb with it lingering at hotter temps each time it trys to level out.
 
Do they have oil coolers? If so the oil will run inline with whatever the coolant is running.
 
I do have an oil cooler. My temps after running for a while are usually 10° to 15° some times maybe even close to 20° difference higher than coolant temps. Most of the time under normal driving conditions im around 10° to 12° difference.
 
The only issue i see is the coolant not hitting the op temp id say you have a dud thermostat.

You will be fine at hotter temps as the cooking system works very well on these trucks your oil temps of 220° is not bad at all
 
Man I've gone through some thermostats. And I worry about that also. And im going to stop freaking out about the 220 oil temps. I'm just wondering how its going to handle towing in 80° or 90° temps. Its crazy how many of these thermostats are bad straight out of the box.
 
Man I've gone through some thermostats. And I worry about that also. And im going to stop freaking out about the 220 oil temps. I'm just wondering how its going to handle towing in 80° or 90° temps. Its crazy how many of these thermostats are bad straight out of the box.
Have you tried a thermostat other than dorman?
 
Yea I've had a motorad and a mopar. May not have been the thermostat at that point though. I was chasing all kinds of issues. I had to do a head job because it overheated and when the mechanics dug into it they found a ton of stop leak. They said the other owners must have dumped at least 2 bottles into it. I'm thinking maybe the stop leak might be the culprit getting in the way of the air bleed valve on the thermostat. It seems to be getting better every time I do something to it. I drained and refilled my coolant a week ago and got some bits of trash out of the system and the mechanics that did the heads flushed multiple times and got rid of a lot of it.
 
Stop leak is the devil. Plugs up not only leaks but small passages well. May want to try a heavy dose of quality system cleaner like sew:

1676740932374.jpeg
 
Stop leak is the devil. Plugs up not only leaks but small passages well. May want to try a heavy dose of quality system cleaner like sew:

View attachment 52147
Yes sir it is. Worse invention ever made. I want to just replace everything at this point. But I may try to do a chemical flush first. Its not running too bad now.
 
What is the original symptom? You say the fans weren't engaging at the right time? What makes you think this? Was the engine actually overheating? 220ish oil temps during normal driving are totally normal for a 6.4 Hemi - absolutely nothing to worry about. Same with coolant temps.
 
What is the original symptom? You say the fans weren't engaging at the right time? What makes you think this? Was the engine actually overheating? 220ish oil temps during normal driving are totally normal for a 6.4 Hemi - absolutely nothing to worry about. Same with coolant temps.
No the fans apparently quit working while I was hauling my camper. After hauling it home I tested the fans and realized they weren't working. 220 isn't that hot but when I'm unloaded and its in the 50's and 60's that kinda concerns me as to what it's going to do when I hook up a 8k camper to the back of it.
 
No the fans apparently quit working while I was hauling my camper. After hauling it home I tested the fans and realized they weren't working. 220 isn't that hot but when I'm unloaded and its in the 50's and 60's that kinda concerns me as to what it's going to do when I hook up a 8k camper to the back of it.
Thats normal temps though and unless you are hitting 110+ degrees outside temp the oil/ coolant temps usually still stick at the same temps they are when its 50 degrees outside thats called operating temp and there is nothing wrong with that. You need to fix the fans though before hauling in high temps
 
Thats normal temps though and unless you are hitting 110+ degrees outside temp the oil/ coolant temps usually still stick at the same temps they are when its 50 degrees outside thats called operating temp and there is nothing wrong with that. You need to fix the fans though before hauling in high temps
10 4 that makes me feel a lot better. Just way hotter than I'm used to.
 
It weirded me out at first too. But I consistently see 220 degree oil and coolant temps unloaded just cruising down the highway with 30 degree ambient temps. Just know they have seriously overbuilt cooling systems capable of bringing things down in a hurry.
 
Yea bro and that does make me feel a lot better. I guess what has me worried is the unknowns. Stop leak in the system. But you guys telling me that those temps aren't too bad makes me feel 10 x better. Especially in 30° temps. What's odd is I noticed my truck seemed to get to 185 190 quicker on 30° days than it does on say a 50° morning. A computers. Oh well either way as long as my fan controller doesn't cause issues I will keep it like It is. A as for now I am loving my autocoolguy fan controller I guess mainly because I can confirm they are pushing when I get out of the truck.
 
@ClayG34 I had the same thought as you about the cooling system the 1st time I pulled heavy (~21k lbs truck and trailer). The oil temp kept rising and what I deduced pulling a few long grades with the truck is this:

Because the Hemi is warm blooded it doesn’t turn on the fan on hardly at all until your oil temp hits 250. ( I think must run an aux fan or at a really slow speed up until 250, which you won’t hit unless you are pulling a pretty steep long grade.) Once the oil temp hits 250, the big boy fan (crazy loud) turns on and the temps quickly drop down to the 215 range and will stay there through the rest of your pull. I first experienced this pulling HWY 14 heading west up into the big horns. This calmed my nerves about the cooling system being able to keep up.

Not a huge fan it gets to 250 before kicking in but with how loud it is, I can see that Ram doesn’t want it turning on too frequently, most people would think there is something wrong with the truck because of the noise level.
 
@ClayG34 I had the same thought as you about the cooling system the 1st time I pulled heavy (~21k lbs truck and trailer). The oil temp kept rising and what I deduced pulling a few long grades with the truck is this:

Because the Hemi is warm blooded it doesn’t turn on the fan on hardly at all until your oil temp hits 250. ( I think must run an aux fan or at a really slow speed up until 250, which you won’t hit unless you are pulling a pretty steep long grade.) Once the oil temp hits 250, the big boy fan (crazy loud) turns on and the temps quickly drop down to the 215 range and will stay there through the rest of your pull. I first experienced this pulling HWY 14 heading west up into the big horns. This calmed my nerves about the cooling system being able to keep up.

Not a huge fan it gets to 250 before kicking in but with how loud it is, I can see that Ram doesn’t want it turning on too frequently, most people would think there is something wrong with the truck because of the noise level.
250 is nothing for a good synthetic oil. The 6.4 in these trucks have oil squirters pointed at the bottom of the pistons- I can guarantee those pistons get hotter than 250
 
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