416C Cat Backhoe, heater not blowing warm air, is there a switch?

[Dougie G]

Hi, I have a 98 416C IT backhoe. I purchased used. It was well maintained and runs good. My heater in the cab only blows cold air. There is a dial on the side panel for temperature control and a hi low switch for the fan. Trouble is it only blows cold air, even when the dial is on high. Its winter now and gets a bit cold in the cab. Is there a switch somewhere that could be shut off or could it be the thermostat is too cold for this climate. I have looked around the engine and above the rear differential and didn't see a ball valve or switch. I can see the cable coming from the dial that controls the heat, and it seems to be working like it should. The machine spent most of its life in a warmer climate. I don't have a shop manual any more, it was lost in our house fire. Thanks

 

[Ntenss1]

there is a toggle switch that has three positions heat, off and cool however on my 450 cat the dial for temp settings is connected to a cable, there is a cable stay that holds the sheath of the cable steady allowing the inner cable to move inside of it and move the blend door from hot to cold. the cable stay broke that holds the sheath and although the dial moved from hot to cold it didn't change the temp. its located directly behind the control panel housing the control knob. hope this helps

 

[Dougie G]

there is a toggle switch that has three positions heat, off and cool however on my 450 cat the dial for temp settings is connected to a cable, there is a cable stay that holds the sheath of the cable steady allowing the inner cable to move inside of it and move the blend door from hot to cold. the cable stay broke that holds the sheath and although the dial moved from hot to cold it didn't change the temp. its located directly behind the control panel housing the control knob. hope this helps

Hi, Thank you for replying. I was under the machine and could see the cable and the switch or 'blend door' and it seemed to be working as it should, moving the switch, on one of the hoses coming from the heater core.

 

[xgiovannix12]

are the hoses warm? maybe there is a shut off on a coolant line

 

[Dougie G]

are the hoses warm? maybe there is a shut off on a coolant line

The hoses are slightly warm, maybe needs to be heated up for a longer period. I only idled the machine for about 45 minutes, I didn't work it while checking the lines. It blows cold air after being worked all day. I did look for a shut off on the the coolant lines, I haven't found one yet.

 

[Tinkerer]

Not many diesel engines will get very warm from a cold start unless they have a load put on them. You could try putting a tarp over the radiator unless it has a summer fan (blows out).
BUT, keep a close watch on the engine temp while it is covered.
this thred may or may not help you. ---->https://www.heavyequipmentforums.com/threads/1999-cat-416e-it-no-heat-heater-valve-location.59531/

 

[AllDodge]

On the left side next to the injection pump is a small brass valve. Its a bit larger then what you find on the bottom of a radiator (T - type). This is used to close off coolant going to the heater in the summer. It needs to be opened

 

[Dougie G]

On the left side next to the injection pump is a small brass valve. Its a bit larger then what you find on the bottom of a radiator (T - type). This is used to close off coolant going to the heater in the summer. It needs to be opened

I did see this brass T valve. Is it open when screwed in or open when screwed out. I think it was screwed out. I did try screwing it in for a while and checked the temp, but it didn't seem to make much difference , but maybe it wasn't long enough, and maybe the machine needed to be worked a bit to warm up better.

 

[Dougie G]

Not many diesel engines will get very warm from a cold start unless they have a load put on them. You could try putting a tarp over the radiator unless it has a summer fan (blows out).
BUT, keep a close watch on the engine temp while it is covered.
this thred may or may not help you. ---->https://www.heavyequipmentforums.com/threads/1999-cat-416e-it-no-heat-heater-valve-location.59531/

I will look into this. Thank you

 

[AllDodge]

Open when screwed out , left loosey

 

[AllDodge]

If all the hoses are warm but the heater ones, then you probably have a clog

 

[Dougie G]

Open when screwed out , left loosey

I think it was mostly screwed out.

 

[Dougie G]

If all the hoses are warm but the heater ones, then you probably have a clog

The hoses didn't seem to warm up that good

 

[AllDodge]

If none of the hoses are getting warm then may need a thermostat. Since it was in a warm climate maybe it was removed, don't know. There isn't a switch, just a cable coming from the rotary dial which opens/closes the air door and the fan switch

Thought of something else, there is a mesh filter under the seat where the heater coil. If its clogged up you won't get much air thru though

 

[Dougie G]

If none of the hoses are getting warm then may need a thermostat. Since it was in a warm climate maybe it was removed, don't know. There isn't a switch, just a cable coming from the rotary dial which opens/closes the air door and the fan switch

Thought of something else, there is a mesh filter under the seat where the heater coil. If its clogged up you won't get much air thru though

I did check the the filter, it was clogged but it is still blowing cold air, so maybe there is no thermostat?

 

[Delmer]

Check the temp of the block after working it for a half hour, the block should be hot enough to not want to keep your hand on it for more than a few seconds, both hoses should be nearly as hot (the rubber will feel cooler to your hand so you might be able to hold them, but they should both feel hot). If the hoses aren't hot, take one off and see where the coolant runs and doesn't, not rocket science. If the heater core is blocked, figure out which way the coolant goes through it, and back flush with a garden hose. If it still won't flow water, then there's another valve in the line.

 

[Tinkerer]

I am quoting Nige's comment from the thread I posted a link to.
"There is no valve shown other than the control valve over the rear axle which is installed in the gap between the 2 hoses at the top left (ringed in red). I would check where the hoses come out of the engine block, shown as Area B, just to make sure that nobody has sneaked a shuftoff valve in there. If you find no valve then the next step would be to disconnect the feed and return hoses at the cylinder block and try to blow through one of them. It should blow coolant out of the other. If it doesn't then either your control valve that"
Did you look for that valve over the rear axle ??

 

[AllDodge]

Don't know about a rear axle valve for the heater, but SIS shows that valve at the block I mentioned

 

[Tinkerer]

I did see this brass T valve. Is it open when screwed in or open when screwed out. I think it was screwed out. I did try screwing it in for a while and checked the temp, but it didn't seem to make much difference , but maybe it wasn't long enough, and maybe the machine needed to be worked a bit to warm up better.

I would be taking that valve off and see why turning it doesn't make any difference in temperature.
Not the temp at the valve but farther away from it on/in the hoses.

 

[kshansen]

Like Delmer says make sure the engine is actually getting hot, not just a little warm to the touch but after working hard for half an hour you should not want to keep a bare hand on the side of the block.

This is one of those time a cheap IR temp gauge could pay for itself fast. Not sure if you guys have Harbor Freight up in BC but something like this: https://www.harborfreight.com/infrared-thermometer-93984.html

I have to remember to pick one up for at home now that I don't have access to the one we had at the shop!

If engine is getting hot but the heater hoses are just a little warm I would say as other have that something is restricting flow. Might just have to hook a garden hose to one of the heater hoses with the other end unhooked and go through the system one step at a time till you find the restriction, be it a valve not working or plugged core or kinked hose.