ok i work for the marine corp in a " Crash barn" ( a garadge for fire trucks) that has no heat in it so i am pretty well dressed to go into work. There was one day we had to go work out in the morning and we were told it was in a gym so i figured t-shirt and shorts, i would be fine. went out started m truck and started driving, it usually warms up quick so i just left the heat on low and defrost. i noticed about 5 miles down the road that i still have no heat. i looked at my temp gauge and she it warm but there is no heat. still after i got to work... no heat. WHAT IT WRONG? and how can i fix this kinda not so litttle problem?

 

It could just be the **** on the switch. The plastic on mine broke where it slides over the stud for the switch. The **** didn't come off but you could turn it but it wasn't turning the switch. Pull the **** off and see if the plastic is cracked.

 

Welcome to the club. There are several similar posts here and no clear answer. I have no heat and have tried flushing the heater core, replaced the water pump, replaced all the hoses, replaced the thermostat, thermostat housing and the ignition coil (a result of letting the alternator slip out of my hands) still with very little heat. My next challenge will be to replace the heater core. After that, I will buy a small 12v heater.

 

before you spend all day changing the heater core. Someone mention flushing CLR in the heater core. I tried it this weekend cause after numerous back flushes of the core I still had no heat for a few years now. He mentioned leaving it in the core only not the engine (although I don't see why not and I may try it again one since I continue getting rust coloring in my antifreeze if I let it cycle through the system.) for only 5 minutes first time and the 15 minutes second time. I did it for a hour first and then flushed with hose in the other direction and then left it in for 1 hour and back flushed for 15 minutes or so at low to medium pressure from hose. I now have great heat.

Some other guys mentioned this to me too and it's safe. Better than changing the core anyday. Also cost much less.

 

That is not a bad idea. I think I will give it a try. It should be pretty easy to do. That sure beats tearing the dash apart.

 

I am having the exact same problem w/ my truck. Sorry to quasi hi-jack your thread, but it didn't seem to make sense to start a new one.

'99 Ram 1500 Sport - No Heat
- temp **** turns freely
- heater core recently replaced (had heat after core fix, then lost it)
- have tried burping cooling system several times

From searches I have found mixed answers, but no real how to's for a fix. VERY OPEN TO SUGGESTIONS, its freakin cold driving around with no heat!!!

Possible causes I have read about:
- Blend Door not operating
- temp **** broken (behind the cosmetic part you see and touch)

Does anyone have any info on how to check, test, and/or fix those items?

Or do you have any other ideas I could try???

Thanks!!!

 

Well, pull the **** off to see if it's broken. That's a start.

 

Here's how I did it. Disconnected both sides of heater core from engine to isolate. Using hose and fittings on the end that would fit inside heater hoses tightly (I actually had to use duck tape on some smaller hose I had around to make it a tight fit. Or you could use garden spray pump to adapt would be best. And pump CLR directly into heater core til CLR comes out the other end of the hose. You'll want to attach a hose into that to to keep away from engine parts like ALT and electrical parts pointing into a bucket. Once you see CLR color come into bucket, let it sit for what ever time you want up to 15 minutes for the first flush. Then stick a garden hose into other hose and push water back the other way for 5 or 10 minutes or clear. Then repeat process with longer times for both processes. Flushing real good when done. At least 15 minutes for me. Reconnect and try your heat. Might want to do radiator if it's suspect too.

Personally, I don't see why we can't flush through engine and whole system at once. But I don't know what the coolant flow through engine involves. CLR or Limaway is pretty strong stuff and will eat away a some materials I'm sure. So until I find out from someone who knows about coolant systems on engines, I'll hold off. I bought a gal of CLR, but only had to use half. I also have 2 heater cores, but only needed to clean one since the rear heat is OK for now. But I think it's a good idea to have done both and radiator. Next time. I wasn't sure it would work.

 

I remember my dad using Drano drain cleaner when I was a kid (in the 1940's). Don't think i would want to do that now with all the aluminum and composite materials in today's engines.

 

Thanks for the tip. I tried it this weekend. It made a marginal improvement. I got 125 degrees out of the vents on the low setting on a 45 degree day. The temp out of the vent dropped to 100 degrees on the high fan setting. I guess if I want to stay warm, I will have to keep the fan low.