Experiencing Luke Warm heat in subzero winter temperature
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From: Rhode Island
Experiencing Luke Warm heat in subzero winter temperature
I have a haunting issue for my 2017 Ram 3500 6.7 Cummins Longhorn Laramie(100,000 miles) when it comes to supplying warm (hot) air in the cab during subzero temperatures:
In the winter months when I am operating on the highway in subzero weather, the heat is luke warm when set to "Hi". I have flushed the heating core numerous times going back and forth with a air compressed water. I did see little results, but that was when temperatures where above freezing.
The coolant temperature hoovers around 194 degrees F.
-Would a winter front grill cover would resolve the issue by raising the coolant temperature thus providing warmer or hot air?
-Any other suggestions?
In the winter months when I am operating on the highway in subzero weather, the heat is luke warm when set to "Hi". I have flushed the heating core numerous times going back and forth with a air compressed water. I did see little results, but that was when temperatures where above freezing.
The coolant temperature hoovers around 194 degrees F.
-Would a winter front grill cover would resolve the issue by raising the coolant temperature thus providing warmer or hot air?
-Any other suggestions?
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From: Clayton MI
If the engine is getting up to temp, the cover won't make any difference at all.
Ya gotta remember though, that the air is heated by passing thru the heater core, the colder the air coming in, the colder the air coming out is going to be. If there is an air pocket in the heater core, then it isn't going to heat the air as efficiently as it should, thus, you get poor performance. If it gets cold enough though.... it really doesn't matter, the heater simply won't be able to warm the air enough to get you toasty warm in the cab. My old Dodge Conquest had that issue. If it was below zero, (F) you could see out the windshield, or, you could have warm feet. You could not have both. My 98 Ram is pretty much the same. Even with that mondo 8.0 liter engine warming the coolant to 195 degrees, heater performance in truly cold weather is abysmal.
Ya gotta remember though, that the air is heated by passing thru the heater core, the colder the air coming in, the colder the air coming out is going to be. If there is an air pocket in the heater core, then it isn't going to heat the air as efficiently as it should, thus, you get poor performance. If it gets cold enough though.... it really doesn't matter, the heater simply won't be able to warm the air enough to get you toasty warm in the cab. My old Dodge Conquest had that issue. If it was below zero, (F) you could see out the windshield, or, you could have warm feet. You could not have both. My 98 Ram is pretty much the same. Even with that mondo 8.0 liter engine warming the coolant to 195 degrees, heater performance in truly cold weather is abysmal.
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From: Rhode Island
Oh No!!! There is no hope other than to hope I have air in the heater core? It's at least a possible remedy, but I will review how to bleed correctly the heater core / coolant system due to possibly leaving air in the system the last time I did it.
What about changing the thermostat to a thermostat with a a higher temperature setting?
Also, I read if the bleed door is stuck open, that may cause the temperatures not to rise properly due to letting in to much cold air that mixes with the warm? I will have to research how to check if my bleed door is working correctly.
What about changing the thermostat to a thermostat with a a higher temperature setting?
Also, I read if the bleed door is stuck open, that may cause the temperatures not to rise properly due to letting in to much cold air that mixes with the warm? I will have to research how to check if my bleed door is working correctly.
Last edited by booch014; Jan 17, 2024 at 04:34 PM.
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From: Clayton MI
Changing the thermostat would make a bit of a difference, but, I bet he PCM wouldn't like it....
If you have one of the camera's on a stick, (don't recall the technical term for 'em.) could snake that down in and inspect the heater/evap core, see if they are getting plugged up with crap....
If you have one of the camera's on a stick, (don't recall the technical term for 'em.) could snake that down in and inspect the heater/evap core, see if they are getting plugged up with crap....
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I know I dont have the diesel engine,,, but I changed my thermostat from a 192 to a 203 one and the truck seems to run better as it is actually getting to the operating temps,,, seems that the 192 wasnt warming up enough and computer was saying engine is cold and adding fuel Stock thermo got engine to 188 F new one now gets to 202 F
Last edited by outlawstorm; Jan 21, 2024 at 04:01 PM. Reason: add
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From: Iowa
If you're pretty sure there are no air pockets in the heater core, then make sure the degas bottle is at least to the full mark, and maybe even a bit higher. As mentioned, if the coolant is getting to temperature avoid anything that might block the flow of air across the radiator. The best those can do is allow the coolant to get up to temperature a minute or two sooner. The worst though is they can restrict airflow enough to allow the engine to overheat. If your thermostat is working properly, there's really no practical benefit to blocking the air into the front grill.
When searching for air flow issues, you probably will want to search for "blend door" rather than "bleed door." Also, if your truck is equipped with a cabin air filter, check that or just plan to replace it. And I think HeyYou was trying to remember the technical term "borescope" or "endoscope."
If you have an IR thermal camera or IR thermometer that can help to confirm whether the coolant into the heater cores is at the correct temperature and if the coolant is flowing through the heater core appropriately. When you flushed the core did the pressurized water seem to flow through it pretty freely? Also, those cores use rather thin aluminum so you probably shouldn't flush them with much more pressure than what the cooling system is designed for (see the pressure cap rating) to avoid locating the weak point in your heating system.
-Rod
When searching for air flow issues, you probably will want to search for "blend door" rather than "bleed door." Also, if your truck is equipped with a cabin air filter, check that or just plan to replace it. And I think HeyYou was trying to remember the technical term "borescope" or "endoscope."
If you have an IR thermal camera or IR thermometer that can help to confirm whether the coolant into the heater cores is at the correct temperature and if the coolant is flowing through the heater core appropriately. When you flushed the core did the pressurized water seem to flow through it pretty freely? Also, those cores use rather thin aluminum so you probably shouldn't flush them with much more pressure than what the cooling system is designed for (see the pressure cap rating) to avoid locating the weak point in your heating system.
-Rod