743 Heater - not blowing very hot air anymore...

Help Support SkidSteer Forum:

ylsf

Active member
Joined
Dec 17, 2007
Messages
39
Hello everyone, We are having an issue with our cab heater on our 743 bobcat. Photo attached: http://img98.imageshack.us/img98/3473/img0899bc.jpg The hoses running to the heater seem "warm" or "hot", the fan is working but it doesn't seem like there is a lot of heat being generated. Is there some kind of thermostat or something that controls the flow of liquid to the heater? Trying to figure out where to start to look at this issue otherwise will have to think about making a service call..
img0899bc.jpg
 

OldMachinist

Well-known member
Joined
May 24, 2006
Messages
2,748
The backside of the heater core maybe clogged with debris or critter nests and not allowing air flow.
 

skidsteer.ca

Well-known member
Joined
Jan 20, 2006
Messages
3,853
The backside of the heater core maybe clogged with debris or critter nests and not allowing air flow.
Sometimes the cores get coated with crud and scale on the inside to and don't transfer heat very well anymore. Canyoufeel any differencein the in and outflow hose temps?
Ken
 
Joined
Dec 6, 2010
Messages
22
Sometimes the cores get coated with crud and scale on the inside to and don't transfer heat very well anymore. Canyoufeel any differencein the in and outflow hose temps?
Ken
You can flush out the heater core on any vehicle.. make a fitting with a T, one side hooks up to a ball valve and a coupler to your air line. the bottom of the T is hooked up to a water line, and the third side has a barbed end to go to a heater core hose. push water through it and then give it a blast of air. the shock and turbulence will dislodge alot of crap, swap the sides and do it from the other direction. I have to do it each year on my old diesel land cruiser. makes a huge difference. no chemicals, no hassle.
 

Kermode

Well-known member
Joined
Dec 15, 2009
Messages
134
You can flush out the heater core on any vehicle.. make a fitting with a T, one side hooks up to a ball valve and a coupler to your air line. the bottom of the T is hooked up to a water line, and the third side has a barbed end to go to a heater core hose. push water through it and then give it a blast of air. the shock and turbulence will dislodge alot of crap, swap the sides and do it from the other direction. I have to do it each year on my old diesel land cruiser. makes a huge difference. no chemicals, no hassle.
Have you checked the coolant level? Low coolant can make a heater blow cold air when there isn't enough to go around. Also, check that the lines haven't got pinched. On my 853, one of the valves that controlled the flow of water to the heater core was stuck in the half off position, even though the indicator showed on. Once that was replaced I was amazed at how well the heater worked. Check the flow of hot water through the core.
 

RickS250

Member
Joined
Jan 22, 2011
Messages
12
You can flush out the heater core on any vehicle.. make a fitting with a T, one side hooks up to a ball valve and a coupler to your air line. the bottom of the T is hooked up to a water line, and the third side has a barbed end to go to a heater core hose. push water through it and then give it a blast of air. the shock and turbulence will dislodge alot of crap, swap the sides and do it from the other direction. I have to do it each year on my old diesel land cruiser. makes a huge difference. no chemicals, no hassle.
SORRY right up front! Do yourself a favor and DO NOT blast air into a heater core! The coolant system is no more then 16 PSI and even if you have both ends open you could get more then that in the core! I have a Radiator shop and I would take both hoses off the motor and flush with a garden hose both ways, it would be better if you could use hot water! Run the water into a bucket just to see what you get out it might shock you what comes out. You don't want to flush it back into the motor either or your just fighting yourself later. Maybe its time to flush the complete coolant system. But like someone said check your coolant level first and make sure that it's full then see if there is good air flow also. I'm GUESSING that the heater core is going to be alum fins with copper tube and if I'm right and its by your feet the alum fins might be getting bad and falling out or just plugs tight. Like I said before SORRY but I have seem heater cores radiators and oil coolers that people have tried to clean/flush that were junk after they were done.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,834
SORRY right up front! Do yourself a favor and DO NOT blast air into a heater core! The coolant system is no more then 16 PSI and even if you have both ends open you could get more then that in the core! I have a Radiator shop and I would take both hoses off the motor and flush with a garden hose both ways, it would be better if you could use hot water! Run the water into a bucket just to see what you get out it might shock you what comes out. You don't want to flush it back into the motor either or your just fighting yourself later. Maybe its time to flush the complete coolant system. But like someone said check your coolant level first and make sure that it's full then see if there is good air flow also. I'm GUESSING that the heater core is going to be alum fins with copper tube and if I'm right and its by your feet the alum fins might be getting bad and falling out or just plugs tight. Like I said before SORRY but I have seem heater cores radiators and oil coolers that people have tried to clean/flush that were junk after they were done.
I was always told to use a graden hose. I did the same fo my car, it had all sorts of crud stuck inside it, i too was told to use a bucket to see what trash came out, it was alloy oxide from when my head got eaten out..... I flushed the engine as much as i could, but there is always some stuck around the cylinders that just won't move. The problem left with the car when it was sold :)
RickS250 - On a side note, is it possible to get a cap for an old style non recovery radiator to convert it to recovery? My dad says you can't, but surely there is a way?
 

RickS250

Member
Joined
Jan 22, 2011
Messages
12
I was always told to use a graden hose. I did the same fo my car, it had all sorts of crud stuck inside it, i too was told to use a bucket to see what trash came out, it was alloy oxide from when my head got eaten out..... I flushed the engine as much as i could, but there is always some stuck around the cylinders that just won't move. The problem left with the car when it was sold :)
RickS250 - On a side note, is it possible to get a cap for an old style non recovery radiator to convert it to recovery? My dad says you can't, but surely there is a way?
When you say recovery are you talking the overflow tank? If the radiator is a brass and copper radiator not a plastic and alum, Yes the filler neck can be replaced with a overflow tube. The problem would be finding a home for the tank.
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,834
When you say recovery are you talking the overflow tank? If the radiator is a brass and copper radiator not a plastic and alum, Yes the filler neck can be replaced with a overflow tube. The problem would be finding a home for the tank.
Yeah, i was looking to add an overflow tank. Its an old compressor and i'm sure its probably not needed but this way it at least has a full belly of water, no air.
I was hoping there was a cap or a way to make the standard cap seal on the neck to make it pull water up from the overflow tank. It uses the larger style caps, 52mm sealing face?
 
Top