I have a 2001 ram 1500 4x4 with the 5.9L. It's about 5 degrees outside today and my engine temp is halfway between 130 and 210. I have a KAT heater plugged in and I let my truck warm up this morning and the cabin heater isn't very hot compared to normal. The truck has always ran a little cooler, is that bad? Would it be a bad thermostat?

 

Bad, or wrong thermostat. Pick up a stant superstat, 195*. It's a bummer to change, especially in the bitter cold weather.... Got a warm place to work?

Burping the cooling system can be a real bear too...... Getting the front, passenger side as high as you can helps. The heater core is, unfortunately, the highest point in the cooling system..... so, just loves to trap air in there, and significantly reduce it's effectiveness.

Welcome to DF!

 

I will try that, thank you for the help

 

I'm having a similar problem - 2000 Ram 1500, 5.9L V8.

Air in the cab is only lukewarm, and only on "1" heat setting. Any higher setting will blow cool air.

Coolant tested at roughly 180 degrees, thermostat replaced twice. It's ACTUALLY 180 in there. We can't see suction in the radiator, the coolant just sits there. It'll run for an hour and never budge over 185.

Top and bottom radiator hoses are both hot.

Water pump replaced

Radiator replaced

Coolant system flush (both ways) 3 times

Heater core blend door moves properly.

It's been burped by a radiator shop, and 3 times by my mechanic.

My mechanic is running out of ideas. Any thoughts?

 

Pull one of the heater hoses apart at the joint above the passenger valve cover. Take the other hose off at the steel pipe going into the water pump. (have a cork handy for that pipe, you can simply clamp off the other hose, engine side, please.)

The short hose is the inlet, long hose is the outlet. Run water into the heater core from the outlet side hose, keeping the inlet hose up as high as possible. Pour water/coolant in until it comes out the other hose.

Hold the outlet hose up as high as you can get it, and reconnect the inlet hose, keep as much fluid in it as possible.

Fill the outlet hose as much as you can, and hook it back up.

That *should* improve the heat.

Option 2:

Cut the outlet hose right by the heater core, shortly after it makes its 90 to run behind the engine. Install a "flush kit" capped T. Pull the radiator cap, start the motor, loosen the cap on the T until you see coolant flowing out steady. (loosen, NOT remove the cap......) Screw the cap down tight, replace radiator cap, let the engine warm up, and see if it is any better. (according to theory, it *should* (there we go again with that word) dramatically improve heater output.

It's a right bear to get all the air out of the heater core.......

 

Run the front end up on ramps, or jack it up as high as you can, run with the radiator cap off till bubbles stop. That's the best way to bleed that I know. That gets the radiator higher than everything else. If you're still running cold, then air is not the problem.

Bad thermostat is very high on the list, but if you change that with the right temp thermostat and it still exists....

A blocked heater core is possible too, in which case flushing with a radiator flush solution is prudent, followed by flushing and back flushing with a water nozzle alternating it on the heater hoses. I actually filled my heater core with the solution via the heater hoses and left it in there for an hour or two. I then flushed with water hose, blew that out with my mouth on one hose, filled with distilled water and blew that out too, followed by coolant. Heat is VERY hot.

If after all that, the truck is still running cold, it's time to block the radiator partially with cardboard so you can get heat and until you can figure it out, but don't overheat the truck. The dash temp gauge is not the most reliable thing.

 

I'm not trying to be a jerk but how do you know? Unless you remove it and check the coupling between the motor and the door itself, you cannot be sure.

 

For those of you with heater problems, a good place to start is with an infrared thermometer. It's a huge time saver and takes a lot of guess work out, plus you can use it for a bunch of non-automotive things. The one I use at work is a version of the 42 dollar Master Cool, that I paid way too much for off the tool truck.

https://www.amazon.com/s/ref=sr_nr_n...41120011&ajr=2

 

OT but, in another thread, someone else mentioned an IR thermometer as a way of troubleshooting a clogged cat (not the four-legged kind). Any truth to this?

 

By the time the clogg starts screwing things up, measuring temp is usually a mute point lol. Do they make a IR that goes that high??


Talking the upstream O2 out is a great way, but a loud way... or take it out and use an Exhaust Back Pressure Tester




BTW, this is how you clear a clogged cat.