Hey guys I'm new here I've been working on a bobcat 753 there is no heat in the cab however the hoses going to and from the heater core are mostly cold so on these ones there's two hoses one from the thermostat housing in one from I believe the water pump or in that area now those hoses come off and there's a split looks like an H two t splits connected together now those hoses are hot before the split and then a couple inches after the split and then they just start getting cold I have taken out the heater core I've flushed it through the inlet and then again through the outlet still nothing I blew out the hoses going from the heater core not attached to the rest of it just the hose is by themselves still nothing any idea would be greatly appreciated
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cdmccul
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- Jun 18, 2013
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Sounds like that "H" is a diverter valve... Is there a box or a control cable on that, or are there a couple ball valves on it?
Maybe you're just low on coolant? The water pumps can't pump air, so if you're low, that might be a problem.
Maybe you're just low on coolant? The water pumps can't pump air, so if you're low, that might be a problem.
So definitely not low coolant I made sure I filled it up topped it off rather. But that H is just hoses and two t splits so it makes it look like an H there are no valves on it there are no cables nothing just hoses t split and hose clamps. Also my boss who owns it had contacted I think bobcat I'm not sure and was asking to get you know a housing for the heater core cuz it's rotted out and I guess he mentions the issue and said that those tea splits are supposed to be there which doesn't make sense to me I mean it does recirculate if the heater valve is off but it is literally hot at that split on both hoses and then about a couple inches down further you know going towards the cab is cold one of them will heat up a little bit but it's like a 60° difference. The coolant seems to be getting in the core heater core but not a lot but there's still not working I flushed out the heater core the other day on both the inlet and outlet ends of the heater core I blew out the hoses from inside the cab those were not connected at the split put it back together topped it off still no heat I even changed the two hoses at the split so the inlet and outlet I reversed them to see if that was the issue but still nothing.
I'm starting to think that maybe it's the water pump or possibly the thermostat but I'm pretty sure the heating system bypasses the thermostat.
The only other possibility that I could think of would be if there's air in there in the system but from what I read at least on a Toyota forum that it usually works itself out within a heating cycle or two I mean I let this thing run for at least an hour 45 minutes to an hour still nothing.
Lowe.Buuck
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Check for a shut-off valve in the heater hoses and also check if the orifice is still in the crossover tube.
Pinch the hose in the middle of the "H". You should feel an area that you can't collapse.
There is supposed to be an orifice in that hose. People have been known to remove that orifice without knowing why it is there.
You can see the part on the www.bobcatpartsonline.com if you look at the Heater Plumbing Kit parts diagram.
Pinch the hose in the middle of the "H". You should feel an area that you can't collapse.
There is supposed to be an orifice in that hose. People have been known to remove that orifice without knowing why it is there.
You can see the part on the www.bobcatpartsonline.com if you look at the Heater Plumbing Kit parts diagram.
As far as that oarfish you speak of when I take the tea off one side there is coolant that comes out through that middle hose or where the orifice should be should there be cooling coming through there when I take the hose off??
Also you mentioned a shut-off valve in the heater hoses what do you mean by that the only valve that I see is the one that's inside the cab where the hoses enter the cab that valve does work it's not stuck or anything.
And back to that orifice if it's not there obviously it should be but what is the purpose of it and cannot stop the hot coolant from going to the heater core
Also you mentioned a shut-off valve in the heater hoses what do you mean by that the only valve that I see is the one that's inside the cab where the hoses enter the cab that valve does work it's not stuck or anything.
And back to that orifice if it's not there obviously it should be but what is the purpose of it and cannot stop the hot coolant from going to the heater core
If I was to bypass that split take that take both t splits out and just make it all one in other words one line going to the heater core and one line coming from the heater core would that work yeah I know it's not supposed to be like that but would that work
thwerench
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Not too sure what those two "T" fittings are in there for, but if bobcat says............., I think if it were mine I'd try to bypass them and see if you get heat just to confirm that the coolant is actually being circulated up there
Yeah that's what I was going to do later to see someone suggested or said that there is or supposed to be an orifice in that small hose that connects to two t-splits together so we're going to see what what happens
So so I have currently got the bobcat running and still not getting hot cooling for the heater core as you can see in the photo I bypassed that split I put a valve in it so I can manually turn off and on right now the valve is off the one I put in so that the coolant will go to the heater core correctly now if you look at where the air filter canister is the hoses start to dip down and then down by the battery it starts going up into the cow right where the canister is it's getting warm but not hot I get more popcorn for the down the hose now than I did before before I bypass the split. I might actually have those two hoses backwards still but either way it should still get hot coolant to the core heater core. also the hose that has an f on it is much cooler than the other hose marked b. also if you zoom in on the photo you can see a zip tie under their breather canister that's where the hot coolant basically stops.
I wonder if there's air in the line preventing the hot coolant from going to the heater core
So I took temperature readings before the valve it's 140° closed and 144° open that's on the thermostat side also on the thermostat side after the valve it is $125° open and 139° closed the hose that is going into the block before the valve is 141° closed and 145° open after the valve it is $127° open and 109° closed the valve itself is between 120 and 122° open and closed the hoses going into the cab literally going into the cab with a water valve is are basically cold they're like between 55 and 60°
thwerench
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I think the next step would be to disconnect the return hose at the valve you've installed to see if the coolant is actually being pumped from the engine through the core and back to the engine
With the engine running. Above idle. You should see coolant circulating. Make sure it's above idle
With the engine running. Above idle. You should see coolant circulating. Make sure it's above idle
Well I think it'd be two cents but I don't know how to really check to see if your water pumps actually working or not I mean it's not overheating the bobcats not overheating so you know and the the police spins you know it's not tight it doesn't make noise I mean it's not loose I don't believe it's bad I'm pretty sure it's good but you never know
Is water/ antifreeze returning in the radiator, thermostat opening and closing, my be open all the time just not heating up ' ,just my two cents
Good questions how can you tell if the thermostat is opening and closing and antifreeze returning to the radiator or in the radiator I mean is there actually a way to tell.
Although when I checked the temperature with my heat gun when the valve is open and temperature is consistent from the hose that's coming from the thermostat housing back into the block so I assume that it is circulating however I'm not entirely sure if it's stuck open or not
Although when I checked the temperature with my heat gun when the valve is open and temperature is consistent from the hose that's coming from the thermostat housing back into the block so I assume that it is circulating however I'm not entirely sure if it's stuck open or not
I think I would verify that there is a 180 degree F thermostat in the system, I believe most machines of that age use. and they can get weak and open to early. you never know maybe it has a 160 in there ,to me it looks like you are running to cold with those readings you gave. diesels need to run around 180 for better effeciency. Now I think 195 is used in new stuff.
Later on today when I go back to the garage to do that I got to basically burp the line so I got to remove the return side and while it's running just to see if I'm getting fluid you know cooling up there up to the heater core
