Miniature railway loco with 2.5 "Banana" Engine Overheating

[VikingSpirit]

Hello all,

New to this forum, but hoping you nice folks can help me out of a bit of a pickle.

Here at the Wells and Walsingham Railway, we have a small Diesel Shunting Locomotive that is running a 2.5 DI (non turbo) "banana" engine through a hydraulic drive.

The engine has been fully serviced with fresh antifreeze, new temperature sensor, new thermostat, fresh oil and new filters all round.

However we are having a problem with the engine running very hot. It has yet to actually boil over, and there is no sign of damage, but the temperature gauge (which has been verified as accurate by dunking the temp sender in a freshly boiled cup of water), says that on warm days the coolant is reaching 120 degrees.

I have heard that these engines do tend to run hot, but can't find any info on how many degrees is too hot?
The engine has a large radiator with fan of about a meter square providing the cooling, but the problem is that the locomotive only ever does a maximum of 9 miles an hour, so the airflow over it is never going to be as much as if the engine were fitted to a transit as Ford intended! This is made even worse when the loco has to run backwards, since there is only a radiator at one end.

As well as finding out the safe temperature limit for the engine, I could also use some ideas for how get the engine to run cooler, preferably without spending mega-money significantly redesigning the cooling system if at all possible.

Is there a thermostat that opens at a lower temperature available for these engines?

thanks in advance

TJ

[twin wheel camper]

Why not pull the thermostat out of it?
Have you changed the water pump maybe it's not pumping the coolant around the system properly.
If it has as you say a big radiator and a fan meter across I don't think cooling it should be a problem unless it really being hammered to drive the pump.
Is the fan a engine driven fan or a electric fan ? If engine driven maybe the engine isn't running at a high enough rpm to drive the fan to provide enough cooling.
I use the same engine to drive a big commercial pressure washer and run it with 2 electric fans 1 running constantly and the other on a thermastat if it gets hot but it's not often it's needed and it's mounted inside a box body so getting no air at all from moving. Mind normally runs at less than 80 degrees and it running 12 hours most days non stop and even on 20+ degree days it has never even went near 100 degrees so I think 120 degrees is way to hot and won't last much longer if you don't get it running cooler I wouldn't be happy unless it stayed under 95 degrees hth

[ake]

I'd also advise an electric fan, and probably throw away the stat.

[VikingSpirit]

thanks for the reply twin wheel camper,

Its good to know that these engine can run cool even when not moving anywhere.

You are right in that the fan is engine driven on our loco, so may not be running fast enough to keep everything cool. Do you run without a thermostat on your pressure washing rig? I'm reluctant to pull the thermostat out completely as the engine does a lot of relatively short runs, so feel its important that the engine warms up quickly / properly (although I suppose too cold is better than too hot)

[the_big_fact_hunt]

air flow shouldnt be an issue as they have been used in narrowboats, , sound very much like an electric fan is needed

[dumper]

You can also try the non water antifreeze as it runs hotter with boiling

[jonochap]

It may be worth checking the water pump as well, the overheating could be a symptom and an electric fan may just be covering it. Is the engine serviced regularly?


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[MinorMatt]

These engines don't run hot in vans...

I haven't got a fan on one of mine at all and its never approached overheating (even in heavy traffic). I would imagine that a hydraulic drive will impose more load than a gearbox in neutral though?

I would also suggest an electric fan would work best.

[DodgeRover]

Is the thermostat working? 120 is way way too hot.

[dumper]

Allso is the rad cor clean it can be just dusty and still stop engine cooling right try washing the fins out with a pessure washer and also flushing out the rad as well

[smokeytransit]

Blocked radiator?