Cooling problems????

[circumsizzle]

My '89 Dodge D250 LE 5.9 Cummins L6 is getting quite warm. It is the first time towing a heavy RV trailer. The temp guage is of the sort that has no actual temp number. My question is this: How warm is the second point just below the H at the hottest point on the guage, and is this normal after just tackling a steep hill towing a kinda heavy RV trailer?
This is my first time here and I look forward to picking ALL your brains in the future for upgrading my Cummins to get more torque. All advise will be GREATLY appreciated.

 

[MIDNIGHT RIDER]

>>> PIN THAT FAN <<<

If you are running a clutched fan, that is the likely culprit.

It does no good to buy another new fan-clutch; we tried no less than seven new ones and not a winner in the bunch.

For years and years, I have been PINNING my fan-clutches, making them fully-locked direct-drive = no cooling issues then.


Recently, from SUMMIT RACING, I found a direct-drive fan-hub and new blades that fit the Cummins.

This brand-new direct-drive hub and blades are laying un-opened in my truck as we speak.

I will post back after I get them installed.


Another likely culprit is the automatic transmission cooler --- providing the truck is an auto.

The cooler on a Cummins is down low on the Starboard side of the engine-block and engine coolant circulates through it.

I am uncertain if there is also a cooler within the radiator, but I kinda think that there is.

If it is an auto, plumb in a BIG remote-mount self-fanned transmission cooler, plus a remote filter-head, along with the factory issue coolers.

 

[MIDNIGHT RIDER]

>>> TEMPERATURE GAUGE <<<

Up high and aft, on the Larboard side of the engine, is the water-temperature sensor.

Plumb in a NPT TEE and nipple, such that the long leg of the TEE is lined up with the sensor hole.

Put the factory sensor in the short leg of the TEE and add a MECHANICAL temperature-gauge into the long leg of the TEE.

A normal Cummins will achieve 180* and stay there, all day and night, up hill and down, regardless of ambient air temperatures.

 

[MIDNIGHT RIDER]

>>> TRANSMISSION TEMPERATURE GAUGE <<<

I am uncertain as to the hows and wheres, as I only own one automatic Cummins truck and it is the wife's; but if the truck is an auto, you need to add a MECHANICAL transmission temperature gauge.

 

[circumsizzle]

Thanks SoSo much. I'll look into those.

 

[oly_fab]

Also if you look at your radiator, the inlet is on the top passenger side and the outlet is directly below the inlet. The radiators in the non intercooled trucks are downflow. So what happens is the coolant comes into the rad and flows straight down to the outlet never hitting the drivers side(some engineers are brilliant). Intercooled trucks the inlet is on the drivers side and the outlet is passenger side, and its a crossflow.....better cooling.

I have 2 90 nonintercooled trucks one a manual the other auto. The manual I have pulled 11% grades pulling my jeep on the trailer and the stock gauge goes to the "H", but once I top the grade it cools rite off. If your staying between the vertical lines between the C and H your within normal operating temps.

Stu

 

[Old timer 12v]

Midnight rider how do you pin the stock fan to cool better

 

[RetiringColt]

>>> PIN THAT FAN <<<

If you are running a clutched fan, that is the likely culprit.

It does no good to buy another new fan-clutch; we tried no less than seven new ones and not a winner in the bunch.

For years and years, I have been PINNING my fan-clutches, making them fully-locked direct-drive = no cooling issues then.


Recently, from SUMMIT RACING, I found a direct-drive fan-hub and new blades that fit the Cummins.

This brand-new direct-drive hub and blades are laying un-opened in my truck as we speak.

I will post back after I get them installed.


Another likely culprit is the automatic transmission cooler --- providing the truck is an auto.

The cooler on a Cummins is down low on the Starboard side of the engine-block and engine coolant circulates through it.

I am uncertain if there is also a cooler within the radiator, but I kinda think that there is.

If it is an auto, plumb in a BIG remote-mount self-fanned transmission cooler, plus a remote filter-head, along with the factory issue coolers.

Did you ever get the new system installed?