Hi, I have a 1996 763F with around 1400 hrs on it. It has the factory cab heater mounted to the left of the operators seat and vents out from under the seat. The heater does not make the cab very warm and will not keep the glass defrosted. I had the bobcat dealer take a look at it and they ended up changing th thermostat. It did not really do much. Does anyone know of any issues with these types of heaters or any way I can make it better or add a second heater? any ideas, thoughts please let me know, Thanks
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antfarmer2
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Look for a mouse nest in it
TriHonu
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Yep, the heaters in the C and F series are not very efficient. G Series heaters can cook you out of the cab.
Check the damper air vane on the heater and make sure it is all the way to Inside Air. If you are getting too much condensation, you may want to move it toward Outside Air to pull more "fresh" ie dryer air into the cab.
Also check the cross-over tube. This is the tube that connects the two heater hoses at the top of the engine. There is supposed to be a restrictor in that 3 inch hose. The restrictor is just a slug of metal with a hole drilled through it. If someone removed it, the hot coolant will just leave the pump, get to the top of the engine and flow through the crossover tube and return to the block. I don't know why people remove them, but it happens.
I had thoughts of replacing the crossover tube with a valve so I could adjust the flow to the heater core. If the crossover tube was blocked off, all the coolant flowing through the heater hoses would have to pass through the heater core, instead of some of it bypassing through the crossover tube.
Some folks have added a 12v fan in the cab to keep the air moving.
After dealing with fogged up windows, and having a window partially opened to deal with it, I removed my door and just dress for the weather. The only time I put the door back on is if I'm blowing snow in the wind. Then the wiper pisses me off since I'm tall and it does not reach the top of the window.
Ok great thanks for the info. I will check that H fitting and may even cut in a valve. We have another blizzard coming in tonight so I will have to deal with it tonight 50+ mph wind should help defrost the windows! Thanks
antfarmer2
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I had a 66 VW bug I wired up a soup can with a candle in it got me by as a defroster lol
TriHonu
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Nothing like a VW air cooled engine in the winter. The only thing worse was a Corvair van; also an air cooled engine but with a much larger cabin space to try to heat.
As an additional thought, on the Bobcat, you might also try foam pipe insulation on the heater hoses if you can keep it far enough from anything hot. I don't know how much it would help, but with the amount of air the cooling fan generates it may be pulling a bit of heat out of the heater hoses. On the newer models M series they changed the cooling fan to a hydraulic fan on demand instead of the fan just running full speed all the time.
My other thought is whether your heater core is plugged internally, or externally (Antfarmers suggestion of mouse nest) or just plugged with dirt. You should check engine temp where the heater hoses leave the engine and compare that to the temp at the heater core. That should give you a starting point to determine if your core is not warm enough, or if you are not transferring the heat from the core to the air.
I installed the Bobcat heater that sits next to the seat in my '99 763F. Since i did not know the orifice size on the bypass/crossover, I installed a brass ball valve in the crossover area. I think that I've found the sweet spot that restricts the flow enough to send sufficient hot water to the heater core. I also installed brass ball valves in the intake and discharge hoses of the heater core lines. They serve 2 purposes. Number one is that I can isolate the heater core during Summer to keep the heat out of the cab as well as being able to shut off the core if it ever leaks. Number 2 is that I can reduce the flow through the heater core a bit and that seems to allow the heat to build up in the core more. I'm no scientist, but it seems to work. Not a blow torch of a heater, but better than an open cab in a snowstorm!
The problem is not a coolant flow issue but an air flow issue. The ductwork design of the c and f series restricts the low pressure blower motor. My solution was to ditch the factory ductwork, unbolt the blower motor and turn it 180 degrees. The blower now blows unrestricted toward the front of the machine. My 773f will now roast you out of the cab.
TriHonu
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Samsonite, you just rotated part 26 in the below diagram so it is pointing toward the door instead of down in to the ductwork?
If that is the case, I'll head to the shop and try it the next time out!
nobull1
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That is interesting about the heater. I am curious to hear what others have to say when they try it. The heater on these machines just suck. Brian
I bought a replacement cab heater from skid steerstuff.com. The model was 2004. Works great compared to the original bobcat factory heater the was ducted under the seat. I completely removed the crossover hose. The only problem is it only blows air at your elbow level. It does a good job of keeping the window defrosted.
