Low Coolant = Low Cabin Heat?

[mtofell]

So, my coolant level was down 2-3 quarts due to the radiator drain valve rattling loose/slightly open (at least I hope that's it - but another topic). I initially noticed the heat output being bad - lukewarm at best, then, the same day, noticed a small puddle of coolant under the front/driver tire and found the leak (fender liner had to come off for anyone in the same boat). I topped it off last night and drove 10-12 miles and it didn't seem to help.

Has anyone had low coolant = low cabin heat? If so, did it come back immediately once you topped off? I fear I might have air trapped in the system and/or the feared clogged heater core that seems to plague these trucks.

Truck is 2014, 6.4 Hemi, 2500. 140K, engine (and radiator fwiw) replaced about 25K ago at the dealer. I never saw a low coolant warning and am a bit surprised at it was at least an inch below the "low" mark on the reservoir.

 

[crash68]

It's most likely trapped air in the heater core. Although the HD trucks do seem to have more issues with the heater cores plugging up, the first symptom is low to no heat on the driver's side, check the heat output on the passenger side.
I don't believe the gasser trucks have the coolant level sensor like the Cummins trucks do.

 

[Burla]

Year one casting sand, you can try running RMI 25 with heater on as much as possible, if this is sand it will be dislodged in Overflow tank for removal. Coolants don't have detergents, RMI 25 is a type of detergent, it's not a lye cleaner which can corrode, it is the opposite.

 

[mtofell]

Update - drove +/- 30 miles this morning and it seems a bit warmer. I didn't have my thermometer with me yesterday but checked today and it's running right around 100F - consistent across all the front vents. Still pretty low compared to what I've seen online where guys were getting about 140F. Yesterday when I was +/- a gallon low on coolant there was almost no heat at all.

After driving today I checked the coolant level and it was back down about halfway between max and min so I'm thinking the air in the system thing is likely. I'm now almost the entire gallon of coolant in. Do you all think over time the air will just work itself out?

And good news - no more leaking. The drain valve at the bottom of the radiator being loose looks like it was the culprit. Thanks Ram dealer (the radiator was swapped out with the engine since it got smashed pulling the engine).

 

[crash68]

Do you all think over time the air will just work itself out?

It should as the HD 6.4 has a pressurized coolant tank which acts like a degas tank which coolant flows through it. You'll probably want to open the pressure cap once the system cools to help burp out excess air.

 

[mtofell]

Another Update - Heat never came back and it looks like I was plagued with the all too common clogged heater core. I guess it was triggered by running low on coolant?

Anyway, I flushed the heater core and am 100% back in business.

I flushed with a combo water/air gun I got on Amazon for $20 and it worked great. At one point I could feel pressure build back into the hose and I can only assume there was a big chunk of crud trying to work itself out. I was using one of those fabric ultra-expanding/contracting garden hoses which worked great as it backing up is extremely obvious as the hose starts to grow.

I wasn't really even looking for sand junk but did notice in the sink after dumping the initial pan that I had a bunch (see pic). After the coolant was worked out of the core I just let it empty onto the driveway. I'm a bit of a special case as my engine was replaced at the dealer with a new factory one so I'm unlucky enough to have two loads of casting crap in my heater core.

Thoughts from the job:

The factory hose clamps SUCK and are a nightmare to get off. I fought it from the top for far too long before just pulling the fender liner and getting it from the side. Once I did that it was super easy.

Even with the clamps removed the hoses are a PITA to work free without damaged them. I'm at 145K miles and 10.5 years so I guess that's to be expected.

I ended going with 90 degree elbows for my flush hose to truck heater hose transition. Also, went with 1/2' elbows and they fit beautifully into the 5/8" (inside diameter) truck heater hoses.

I flushed for about 10 minutes in each direction, going between air and water. I set the compressor at 40psi and water whatever it comes out of the sprayer at. Fwiw, the opening on the sprayer is quite wide which results in pretty low pressure. I thought of going longer but with the one big chunk episode I was confident and also didn't want to stress the core any more than necessary. And with traditional clamps on and the hoses freshly removed, the job would be super easy to do over. By far the worst part is re-installing the fender liner.

Overall, super thankful for the info here and on the net and it's a pretty easy job. I'm really not great working with cars/trucks anymore but got through it (did a lot when younger but was luck to have a company owned truck for 20+ years and never touched it). If you have a decent set of tools and even some basic mechanic skills you can get through it.

 

[Burla]

Nice good job, did you flush so you could see debris? See sand?

I'd run rmi25 through that, makes the system like new.

 

[Gwerner74]

Glad to hear that worked for you as I'm about to the same thing this week. Same symptoms as you on my 2015 2500. Max 100 degrees out of the vents right now and I'm tired of relying on the heated seats and wheel to keep me from freezing in the winter. Great tip about pulling the fender liner, I was not looking forward to fighting with the hoses up at the firewall.

 

[mtofell]

did you flush so you could see debris? See sand?

I'm not sure if I saw any running through the hoses as I was doing the job. I purposely bought clear hose in hopes but it was hard to distinguish between air bubbles and sand/debris. Also, in reports I read online, people weren't able to see or recover much of anything so I didn't have high hopes. Finding the crap in the sink afterwards was kind of on accident.

Great tip about pulling the fender liner, I was not looking forward to fighting with the hoses up at the firewall.

When I first looked I thought it would be easiest to get to the hoses right at the firewall but I quickly abandoned that. Those factory clamps are just a nightmare to deal with. Maybe I don't have the latest/greatest tools for them?

Anyway, I just can't see how this is possible w/o pulling the wheel well guard and going from the side. Once that's out of the way everything is just right there. If you're sourcing supplies I bought 5 feet of clear hose and cut it in half for 2.5/each. It worked but I'd go for 8' for 4'/ea side if I had it to do over. I ended up getting wet from the hose flopping around. 4'/ea side and I'd have been able to pin it on the ground with my foot.

I hope I didn't beat up the hoses too bad getting them free. I guess time will tell but so far everything looks good and no leaks. They looked okay but between the dents from the factory clamps and the damage I did twisting/freeing them with pliers I'm going to keep an eye on them.

 

[Wild one]

I'm not sure if I saw any running through the hoses as I was doing the job. I purposely bought clear hose in hopes but it was hard to distinguish between air bubbles and sand/debris. Also, in reports I read online, people weren't able to see or recover much of anything so I didn't have high hopes. Finding the crap in the sink afterwards was kind of on accident.



When I first looked I thought it would be easiest to get to the hoses right at the firewall but I quickly abandoned that. Those factory clamps are just a nightmare to deal with. Maybe I don't have the latest/greatest tools for them?

Anyway, I just can't see how this is possible w/o pulling the wheel well guard and going from the side. Once that's out of the way everything is just right there. If you're sourcing supplies I bought 5 feet of clear hose and cut it in half for 2.5/each. It worked but I'd go for 8' for 4'/ea side if I had it to do over. I ended up getting wet from the hose flopping around. 4'/ea side and I'd have been able to pin it on the ground with my foot.

I hope I didn't beat up the hoses too bad getting them free. I guess time will tell but so far everything looks good and no leaks. They looked okay but between the dents from the factory clamps and the damage I did twisting/freeing them with pliers I'm going to keep an eye on them.

You need a set of these.
Even these ultra cheap versions will work on most hose clamps.

Amazon.com

Amazon.com : Hose Clamp Pliers

 

[Gwerner74]

You need a set of these.
Even these ultra cheap versions will work on most hose clamps.

Amazon.com

Amazon.com : Hose Clamp Pliers

What kind of sorcery is this? Ordering a set of these immediately.

 

[04fxdwgi]

What kind of sorcery is this? Ordering a set of these immediately.

You will not regret the purchase. I found them really useful on my 26HP Zero turn mower and my 454 Mag boat motor. Neither has room to get hands and pliers in to remove the factory clamps.

 

[EdGs]

I will third that recommendation on the pliers.

Up there with the Gearwrench tool for the spark plugs.

 

[bacaruda]

Think you could flush core from hoses on water pump?

 

[bacaruda]

Second try, can you flush core from hoses at water pump?

 

[Wild one]

Second try, can you flush core from hoses at water pump?

Is the 09 in your avatar the truck you're asking about?
On it yes you could flush it by disconnecting the hoses at the water pump,on a later truck with the 8 speed transmission not so much

 

[Gwerner74]

Nice good job, did you flush so you could see debris? See sand?

I'd run rmi25 through that, makes the system like new.

So on this RMI-25. I'm attempting to flush my plugged heater core on Saturday, and assuming it works my thoughts would be to do the following.

- Add a bottle of RMI-25 to the existing coolant.
- Drive for a couple hundred miles (maybe more needed?) to let the RMI-25 do its job.
- Drain and flush the entire coolant system.
- Add a bottle of RMI-25 to the new coolant.

Does that make sense, or am I wasting my time with the plan to drive a couple hundred miles with the RMI-25 before flushing the rest of the system?

 

[04fxdwgi]

Second try, can you flush core from hoses at water pump?

Be real careful. The operating pressure on the vehicle is like 17 psi MAX. Some water supplies exceed 60 psi.

 

[bacaruda]

ok on pressure, we have well pump don't know psi. I was going to try spray nozzle
though. Might run some of that -25 for a bit first.
Thanks

 

[turkeybird56]

well pumps are 40-60 psi. This could vary depending upon pressure switch cut-off (on pump), and pressure tank setting.