
Article at Barrington Diesel Club
Engine Fans and Fan Shrouds
Initial basic steps.
Paying attention to the condition of fan shrouds and the fan position in relation to the shrouds will solve many overheating problems.
The images on your right are out of my very old Detroit Diesel Training manual. Still, principles are principles; 2+2 will always equal 4.
It is very important not to have gaps between the fan shroud and the radiator. The shroud must completely seal off the radiator so that all the air
goes through both the radiator and the shroud mouth. Any gaps whatever may cause overheating problems.
Attention to these points have helped me solve many heating problems in the past, and if you want you can download the whole excerpt, which we've put into a pdf document.
Both Customer and Cummins Small Cam engine Boiling!
Hey you! Come fix your engine - it's boiling!
The customer complained bitterly 'You did my engine. We stored it for a couple of months until we needed it -
Now we put it in and it's overheating! -
Come fix your engine!


And he caused big problems. Much of the engine had to be stripped before we found the problem. But still, I feel and empathy with mother nature when I imagine the course of his death and witness the last of his remains.
My ADE 407 is Overheating - Jay says - Give me pointers, Please!

The motor is a ADE 407T. At the very least, would you be able to flag common issues that cause these motors to over heat so bad....I really am trying to help here, My brother stripped and replaced a couple of components this week, there was one pistons ring that had snapped and it was replaced etc. I was glad to hear when he told me yesterday that the motor is running so smooth and quiet, but after doing some work and exposing the truck to some load, the over heating is back.
Hi Jay,
I've tested many diesel engines in my life but only very rarely was a fault outside of the cooling system the cause of an engine overheating.
Re: Overheating ADE 407TI am not aware of any general problem with overheating on any ADE engine. I have had occasions in the past, when after overhauling and testing an engine, we would give it back to the customer and it would be overheating in his machine or truck, and then we would have go to investigate, often the original cause of failure would be discovered at this stage.
Here are some of the things we've found when correcting overheating in the past:
- fan damaged
- fan reversed
- fan slipping
- fan belt loose or wrong size or slipping
- fan drive pulleys badly worn
- radiator blocked or restricted (measure temp in and temp out, approx 10 degreesC variance required)
- fan cowling damaged or missing (equals no pull or push of air through the radiator)
- fan position incorrect e.g. not in radiator cowling (position depending on fan type, but at least one third in)
- fan too small for radiator cowling (equals no pull or push of air through the radiator)
- thermostat removed or faulty (equals water, or not enough water, getting to the radiator to be cooled)
- water pump problems - not working properly, incorrect impellor, incorrect clearances (check flow).
- cooling system restriction, water flow blockage
- hose or pipe restriction or blockage
- radiator cap faulty
My Detroit Diesel 6V-53 has a serious overheating problem!
Could that lead to the overheating?
and what could be the cause of that and the overheating? Radiator is OK, V-belt & fan OK, Oil pump has been replaced.

A common problem casuing 6V-53's to overheat is the wrong rotation impellor in the water pump. I've seen it many times. Have you recently overhauled or changed your water pump? Did it overheat before?
Re: 6V-53 Oil supply to rockers
Oil supply problems have nothing to do with the water cooling, you have two distinct problems.
Make sure your oil galleries are open by blowing air through them, and especially check if your cam bushes did not spin and block your oil gallery. I can give you more info, depending on your reply.