Dodge Cummins Diesel Forum banner

1 - 20 of 84 Posts

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #1
So I would have put this thread in regular drive train, but I have several performance mods.

Here it is, I changed my thermostat once to a generic Autozone one. Towed my toy hauler to camp and it spike 230 degrees.
Figuring it was a junk T-stat, I ordered Cummins spec Stat from Thoroughbred diesel. Installed and same problem.

I already changed my Radiator to an all aluminum 3 core, with twin 1250CFM fans. Along with new water pump
Flushed radiator 2x and ensured proper mixture of fluid, even a little lean with more distilled water than fluid.

After all this while towing the same route as before I am running 230 degrees. My boost is 30lbs and EGTs are 1100.

I was going to re-torque my head to see if there's and issue (did this on chevy 350's all the time). And replacing my Sensor as well.
My mods are simple but there nonetheless
4k springs. (never rev past 2250rpms)
#10 fuel plate AFC tuned
Timing advanced but unkown timing (done before I purchased)
I am sitting at 383 hp and 893 torque. Dynoed 4 months ago

Any other thoughts, I am thinking I may have gotten a botched radiator and can't rule out a new component
 

·
Registered
Joined
·
588 Posts
After all this while towing the same route as before I am running 230 degrees. My boost is 30lbs and EGTs are 1100.
30 lbs/1100 degrees constantly, on level ground? Them's uphill grade numbers for me and my 5er, and 230 degrees is not surprising at that point if you're running that much power for a long period of time. You towing @ 80 mph or something?
 

·
Registered
Joined
·
17,072 Posts
Even with my 4 row, icebox radiator I'd be overheating if I sustained 30 psi of boost and 1100 EGT. Your electric fans probably draw less air than the stock fan BTW. Do you have a fan shroud and do you still have the front spoiler?
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #6
30 lbs/1100 degrees constantly, on level ground? Them's uphill grade numbers for me and my 5er, and 230 degrees is not surprising at that point if you're running that much power for a long period of time. You towing @ 80 mph or something?
Clarify, thats when I am towing up hill on a grade 2-3 miles less than 5% speed is somewhere between 55-60 and RPMS are between 1750-2000 depending on speed. ETC on mormal grade i am down to 650 EGTs and 2-5 psi on boost. My toy hauler only weighs max 10k its never been to that capacity weight configuration has been roughly8k
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #8
No mechanical fan? Or are the electrics supplemental?

Deleted the original fan, and upgraded with two electric fans with a fan shroud surrounding both fans. I will get a link as well to show pictures. they are on as soon as the truck turns on, i didn't bother with a temperature relay.
 

·
Registered
Joined
·
588 Posts
Clarify, thats when I am towing up hill on a grade 2-3 miles less than 5% speed is somewhere between 55-60 and RPMS are between 1750-2000 depending on speed. ETC on mormal grade i am down to 650 EGTs and 2-5 psi on boost. My toy hauler only weighs max 10k its never been to that capacity weight configuration has been roughly8k
But you are seeing the 230 degrees consistently on both level ground and uphill grades? Or just on the uphill grades? And only while towing?
 

·
Premium Member
Joined
·
419 Posts
Deleted the original fan, and upgraded with two electric fans with a fan shroud surrounding both fans. I will get a link as well to show pictures. they are on as soon as the truck turns on, i didn't bother with a temperature relay.
Electric fans may be a performance upgrade in that they don't take as much HP from the engine to turn as a mechanical fan would, leaving that extra HP available for use at the wheels, but I doubt they are a cooling/ airflow CFM upgrade.
They're far more likely to be an airflow CFM downgrade from the stock mechanical fan with the one possible exception being with the truck stopped and the engine at idle. And even then if the mechanical fan clutch locks like it should when temps get high, the mechanical fan may win at idle too.
.
.
.
 

·
Premium Member
Joined
·
539 Posts
In my opinion there's no 'may' about it.
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #12
But you are seeing the 230 degrees consistently on both level ground and uphill grades? Or just on the uphill grades? And only while towing?
No it cools down significantly when not towing uphill, once I start a climb, the temp gauge goes to 230 redline quickly, when I am not towing it never gets above 190.
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #13
Electric fans may be a performance upgrade in that they don't take as much HP from the engine to turn as a mechanical fan would, leaving that extra HP available for use at the wheels, but I doubt they are a cooling/ airflow CFM upgrade.
They're far more likely to be an airflow CFM downgrade from the stock mechanical fan with the one possible exception being with the truck stopped and the engine at idle. And even then if the mechanical fan clutch locks like it should when temps get high, the mechanical fan may win at idle too.
.
.
.
I bought two mechanical fans from NAPA, I did this first because I couldnt hear the fan/ hurricane noise from under the hood when it overheated when towing the first time, like you should hear. I bought one it didn't change anything figured it was a new bad clutch fan and returned it got another one and still no change in spiking temps. I have heard of upgrading to the 3rd gen fan but never researched it, to see the difference.

this is the radiator fan similar setup I have on my truck right now

https://www.ebay.com/itm/3-Row-Radiator-Shroud-Fan-FIT-1994-02-95-97-Dodge-Ram-2500-3500-5-9l-Cummins-L6/323805874393?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649
 

·
Registered
Joined
·
87 Posts
the water pump would be my next big suspect in this case... after that it would be water jacket clogged up with rust or something if it had been run by a previous owner without proper antifreeze mixed in.
 

·
Registered
Joined
·
17,072 Posts
I bought two mechanical fans from NAPA, I did this first because I couldnt hear the fan/ hurricane noise from under the hood when it overheated when towing .......
Parts store fan clutches are famous for not fulling engaging. The little extra cost of OEM is far less than the cost of what you bought.
 

·
The Uppity 12v Admin
Joined
·
8,215 Posts
Electric fans are much more efficient and mine work as well as I personally need them to, but they are absolutely not an upgrade in terms of raw airflow.

Stock mechanical fans are purported to move "over 10,000 CFM" and draw "more than 25 hp" out of the crank with the clutch fully locked.

My Volvo electric fans are capable of moving almost 7,000 CFM with a draw of about 1.75 hp out of the crank. An unloaded truck doesn't need a fan at all unless you're sitting in traffic and ambient temps are high. Mine barely turn on in normal driving. When they do, it's one fan on low speed which draws .65 horsepower out of the crank for (generally) 30 seconds or less. In my opinion that's much better than a mechanical fan that always draws a couple horsepower unlocked whether the airflow is needed or not.

My Volvo fans can handle a sustained 25-30 psi in 80-degree temps at lower elevations. This is also with a coolant filter which diverts flow from the radiator. I have not tested it with the filter valved off. I rarely run the truck harder than that in a sustained load scenario so it works for me.

Putting your mechanical fan back on with a genuine Mopar clutch will get you the best performing cooling system possible. 400 horsepower at the wheels is at or past the limit of a 2nd-Gen cooling system in good working order depending on environmental conditions.
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #17
Electric fans are much more efficient and mine work as well as I personally need them to, but they are absolutely not an upgrade in terms of raw airflow.

Stock mechanical fans are purported to move "over 10,000 CFM" and draw "more than 25 hp" out of the crank with the clutch fully locked.

My Volvo electric fans are capable of moving almost 7,000 CFM with a draw of about 1.75 hp out of the crank. An unloaded truck doesn't need a fan at all unless you're sitting in traffic and ambient temps are high. Mine barely turn on in normal driving. When they do, it's one fan on low speed which draws .65 horsepower out of the crank for (generally) 30 seconds or less. In my opinion that's much better than a mechanical fan that always draws a couple horsepower unlocked whether the airflow is needed or not.

My Volvo fans can handle a sustained 25-30 psi in 80-degree temps at lower elevations. This is also with a coolant filter which diverts flow from the radiator. I have not tested it with the filter valved off. I rarely run the truck harder than that in a sustained load scenario so it works for me.

Putting your mechanical fan back on with a genuine Mopar clutch will get you the best performing cooling system possible. 400 horsepower at the wheels is at or past the limit of a 2nd-Gen cooling system in good working order depending on environmental conditions.
Found a guy on Craigslist that has a cooling shroud and fan, ( i threw my stuff out and returned the cutch to NAPA) so this weekend I am putting the shroud back on and fan along with an OEM clutch from DAP. I will see if it returns to normal, I replaced water pump as well. if it still heats up then I will get the block cleaned and flushed.
 

·
VA Chapter VP
Joined
·
1,329 Posts
Discussion Starter #18
Dauntless89, would you suggest an auxillary cooling bypass radiator placed elsewhere on the truck along with original cooling fan setup? Since I am at the max hp for 2nd gen cooling design.
 

·
Registered
Joined
·
588 Posts
Since I am at the max hp for 2nd gen cooling design.
Except you're not, really, unless you have the pedal all the way on the floor when you're towing up those hills. I suspect you may have a clog somewhere in the coolant system and you're not getting full flow. An aux cooler _might_ help you a little bit, but if you're not flowing enough, extra rad surface area isn't going to help much. Have you tried taking it to a shop for a coolant flush, where they got the special chemicals and pumps and can power it through in reverse to knock stuff loose?

I guess I gotta ask too, your electric fans are hooked up to pull air backwards through the radiator right? At highway speeds your fans shouldn't be really doing much of the work anyway, but if they are wired backwards and fighting the airflow, that would be a problem. I would really also suggest not running them 100% of the time, but that's another issue.

Somebody asked a little bit further back in the thread if your lower air dam is removed, as well? That helps create a lower pressure area behind the radiator. There's a rubber flap at the bottom of the radiator kinda inside the bumper as well that could possibly have rotted out or been removed.

One last suggestion is to make sure your intercooler and A/C condenser aren't totally clogged up with dirt or bugs or anything. They do get that way :)
 

·
Premium Member
Joined
·
4,668 Posts
Throw a coolant filter on it. You will be amazed the trash that gets picked up in "clean", well maintained cooling systems.
 
1 - 20 of 84 Posts
Top