New truck '01 Dodge Ram; Old truck '99 Dodge Ram; both 318's

I have been trying to fix the heat on my truck lately. The air in the old yellow ram got really hot. On a winder day I couldn't leave it on full blast all the way to work, I had to turn it all the way down or even off. Well a coworker made mention at lunch a couple weeks ago when it was cold out that my truck didn't get very warm. She was right, it was only like luke warm air. So first I replaced the radiator cap, no change. Then I figured maybe the heater core and stuff had gunk in it. So I bought this cleaner stuff by Prestone that you empty the radiator and pour this in, and then fill it the rest of the way with water. You log 3-6 hours on the vehicle, then flush it out. Well I put the stuff in Sat. By sunday, the heat was hot! Just like the old truck. I was happy. I ran about 5 hours total over the last few days. Wed night I then backflushed the entire system. There was just like dark brown water pouring out for like 5 minutes. I then drained the water out and put in the antifreeze per the instructions; one bottle full, then fill the rest of the way with water. Run the truck for ten minutes, let cool, then fill the rest of the way with more anitfreeze. Now, my heat is back to luke warm again. UGH!!

Last night I replaced my thermosat with a factory 195 one (I can only assume the old one was also 195). No change. Before this while driving home from work, I did notice that the air was warm (not hot) when my foot was on the gas, but when I was coasting or idling, it was cooler. I also checked the fluid mixture before I replaced the thermostat, and it was only good to ten degrees above zero, so it wasn't even a 50/50 mix yet.

I'm pretty much at a loss now, and I like my windows to defrost.

 

feel the heater hoses going into and coming out of the heater core,they both should be real hot. If one is hotter than the other ,then I would say your core is plugged up.If there both cool I would say your coolant level is low or there is air in the system. also check your fan clutch

 

put in the antifreeze per the instructions; one bottle full, then fill the rest of the way with water. Run the truck for ten minutes, let cool, then fill the rest of the way with more anitfreeze. Now, my heat is back to luke warm again. UGH!!

where did you get these instructions? ive always used straight 50/50 and i just looked in the haynes manual and it says to fill with 50/50. if your mixture is wrong your heat wont be right.

and i think that your temp on the truck should have been higher for your truck to be running for 20 minutes without having air flowing through the radiator. but im not too sure. you'ld have to check with some of the other guys around here for that

 

I got the instructions off the back of the Prestone Antifreeze bottle.

I'll check the hoses tonight when I get home.

How do i check my fan clutch?

 

youre mixture is supposed to be 50 50. since not all radiators are the same i cant imagine how those instructions could apply to all vehicles. if i were you i would drain and do it again with 50 50

 

When it starts to get cold around where I live (32-40 degrees), my truck will not be any warmer then that after a 20 minute idle. Back in May, on a field trip for school where I had my truck. I started it up, then the professor decided that he wanted to have a discussion...30 minutes later in sub freezing (like 20-25, I'm not sure because we were 45 miles from the nearest thermometer) my truck was still lower on the temp gauge then his.

 

you already found your problem... the brown gunk coming out is not all the way out. what i'd do is drain it again and flush it several times with fresh water until that water comes out clean. Then to give it more help... add the cleaner again to it (optional) and run it again for 3~5 hours then repeat the flushing cycles until all you get out is clean water. THEN fill up with the antifreeze and DISTILLED water. tap water was used previously and thats why you have crap in there to begin with.

 

Well, i did flush it until all the brown gunk was gone, whaich is what the directions told me to do.
The old truck wasn't bothered by tap water though. I'll have to give distilled a try.

 

Haven't done the distilled water thing yet, but I did check the heater hoses today and they are both warm, jsut like the radiator hoses. Warm. No one knows how to check the fan clutch?

 

symptoms of failure is noisy operation, loosenes, vibration and evidence of silicone fluid leaks.

rock the fan back and forth to check for bearing play.

turn the blades by hand and make sure it turns freely

inspect for substantial fluid leakage from the fan assembly, a deformed bi-metal spring or grease leakage from the cooling fan bearing. replace the fan clutch if any of this happens.

now warm the engine to operating temp and turn truck off. disconnect the battery. turn the fan by hand. you should feel some resistance. if it turns freely replace the fan clutch


got this all from the haynes manual.
i still say your problem is all in your mixture... whether you have distilled water or not. i dont think youve got it right.