B6100 D650 cooling system

[4x4forks]

I have a Early B6100 with a D650 engine . It has a Siphone cooling system. Has anyone tried fitting an electric pump ?
What are the pitfalls, Is it any better as later machines have a belt driven waterpump.

 

[rentthis]

Is it running hot? If not, don't fix it.

 

[torch]

I don't think any version of the B6100 had a water pump.

 

[85Hokie]

as said ....if running hot - fix reason WHY. Other wise allow that hot water to rise and fall and cool! Works very well!

 

[procraftmike]

As others have said, the system works fine. I have a 1977, B7100 that uses this system and if the radiator is in good condition and you keep the front screen clear, the system works like it should.

One thing you might want to consider though, is to add a coolant temperature gauge. There are several threads on this site about it.

 

[4x4forks]

I have fitted a temp gauge and it is running hotter that i would wish under load. Cooling system is currently in A1 condition. They thought it would be better as newer engines all have waterpumps

 

[torch]

One advantage of the thermo-siphon system on a small tractor is that it is essentially free horsepower. Instead of a mechanical pump that requires engine power, the T-S system is powered by waste heat.

Ok, it's not a lot -- maybe 1/4 or 1/3 hp, but hey, when you've only got 12hp at the pto to begin with, every little bit helps!

 

[85Hokie]

I have fitted a temp gauge and it is running hotter that i would wish under load. Cooling system is currently in A1 condition. They thought it would be better as newer engines all have waterpumps

What is you temps top of radiator? More importantly - what are temps at bottom of radiator?

Top of block entering radiator should be 200+ F .......210 is ideal. This is a hard worked engine btw.

At bottom neck of radiator should be 70 F less - or 130/140...... If you do NOT have 50 degree drop, something aint good I have seen 100 F drops....

50/50 WILL not cool as 70/30 water to ethylene glycol.........so, unless you are going to spend temps in the teens (F) then you will like the 70/30 mix!

 

[4x4forks]

Thanks the information it is very useful. I am running a 70/30 mix.
I was seeing around 110'c which is about 230f top hose. Bottom hose was around 80c around 160f so radiator doing its job ok.

 

[4x4forks]

Update.
12v electric cooling pump fitted in replacement of bottom hose. Motor running on variable switch to adjust speed.
Will test under load shortly

 

[motorhead]

Update.
12v electric cooling pump fitted in replacement of bottom hose. Motor running on variable switch to adjust speed.
Will test under load shortly

Don't pump the coolant too fast because it will have a shorter time in the radiator which is your heat exchanger. I had the little B5100D and it had no water pump. I ran a 48", 3 blade 3 point mower and it did just fine. Keeping the RPM up so you have good cooling fan speed which is necessary for thermosiphon.
There is a saying about vehicles or equipment that never came with gauges.....
"You never worried about the **** until you put a temp or oil pressure gauge on it" Old AIR cooled VW's owners manual said that in HOT weather, the oil pressure light might come on at IDLE. It is okay as long as it goes off when the engine revs above idle. VW oil light switches didn't turn on until 2 psi of oil pressure.

 

[85Hokie]

Don't pump the coolant too fast because it will have a shorter time in the radiator which is your heat exchanger.

Excellent point!

THIS is exactly why pulling a thermostat out of system is a bad idea......TOO fast of movement does not allow cooling!

And for the record - 230 is a bit high on the top side....160 on bottom...still too hot.

Radiator is not doing the job there.......

Before changing all the plumbing ....I would remove all liquid......clean internal system several times.....change out with water to wash, and then replace coolant......

IF you pump water through and see a lower temp - that could be good and bad, if the water is moving too fast the reading of the water will be true - but cooling of the head/block will not be known.

report back your findings

 

[North Idaho Wolfman]

There are 2 sides to the coin on adding a water pump to an engine that does not have a thermostat.

One: Your not able to regulate the temp on the engine, so moving water around when it's not ready or warmed to operating temp is bad.

Two: Your moving the water too fast and it does not have time to cool.

I personally wouldn't suggest what you did because there is no way to properly control it, besides, there are millions of these thermosiphon cooled engines working in all sorts of conditions without issues.

It sounds to me like you might be compensating for a failed part, be it a blown head gasket, cracked head, leaking system, corroded system, or internally or externally plugged system.

 

[4x4forks]

UPDATE!
Well i have been rotavating with a 1200 in heavy clay. I have been watching the temperature very closely and checking the temp around the engine. Rear of the block front of block, head, sump, top and bottom hoses, Top and bottom of rad.
The result is I am running the electric water pump at around 1/4 of its max speed as it is cooling the system very well.
I am sitting the temp at around 95 degree celsius.
From my conclusions I would say this is defiantly a improvement from standard and works very well.
I know that there are many who would only consider a standard setup but I wanted to see if it could be improved upon.

 

[motorhead]

That's 203 degrees F. If you think it is better then that's good. My B5100D would bubble out a little coolant when I was running a 4 ft mower in 2 foot high brush under high load. Did that for years and it was a thermosyphon. It didn't have a gauge so there was nothing to look at to worry. I'm sure it was good and hot though.