Heater issues

Dittmerdiesel · Oct 19, 2012

I just had almost the exact same problem. Wasnt blowing hot and there was a slight coolant smell. The heater core was bad and leaking. Replaced it, and now good as new!

6speedsd · Oct 20, 2012

I assume the whole dash has to be removed to change a heater core right?

Dittmerdiesel · Oct 20, 2012

Yes, it does. I had a relay bad as well that was causing problems.

6speedsd · Oct 21, 2012

Just seems weird to me that sometimes it blows toasty warm then others just mildly warm. Figure if heater core was clogged I wouldn't get heat at all, or very little. Same thing with blend door. It never just blows cold air. It always blows at least mildly warm. But morning when it's in the 30's, mildly warm doesn't cut it! Especially when I have my 2yr and 6mth old boys in the truck with me.

lenzhotrod · Oct 25, 2012

Simple test on the heater core is hold both lines to the core. If one is hot and one is very cold your core is plugged.

6speedsd · Oct 30, 2012

Ok, the control valve that's in the upper hose...is the plunger supposed to be in or out when the heat is on?

907DAVE · Oct 31, 2012

I am shocked no one has said head gaskets yet!

Heater performance is the first sign of failure.

907DAVE · Oct 31, 2012

Does the heater produce more heat at idle than at cruising speeds?

If the answer is yes, start saving up.

6speedsd · Oct 31, 2012

No just the opposite. More heat at cruising speeds. I'm pretty sure it's my heater core. I read somewhere about flushing it with CLR. Unhook both hoses, flush with water, then pour CLR in and let it sit for a few hours. Might give that a try this weekend.

Dittmerdiesel · Oct 31, 2012

If your heater core is clogged, then you might want to flush the whole system. If it clogged once, then it has a good chance of clogging again. Flush the system and add a coolant filter if you don't already have one.

907DAVE · Oct 31, 2012

Just for giggles try running the engine with the degas cap off until the thermostat opens and see if you get any "gurgles" during this period.

Dittmerdiesel · Oct 31, 2012

^^ Im assuming this would tell you that the hg's are blown?

6speedsd · Oct 31, 2012

System was flushed back in May when I put a new oil cooler on. Could have washed some debris in there when I did that. Didn't own the truck last winter so I don't know if it had any issues then or not.

Really don't think I have a HG issue. Never had symptoms of that at all. No reason to start thinking that now.

6speedsd · Nov 3, 2012

Started pulling hoses today to flush the core. Pulled the control valve in the upper line and started looking at it. Rubber diaphragm had bunched up, keeping the valve from opening fully. Went to dealer and got a new one. Truck seems to blow hotter air now for sure. But still cools off when idling. Letting it cool back down and going to give it a good flushing anyways to see if it helps any more. Making steps in the right direction anyways.

e.nickkk · Nov 3, 2012

my heater core was plugged up also I used the (Works) from walmart it clean out a bunch of crap and works fine now

6speedsd · Nov 3, 2012

Pulled the hoses and sprayed water back through it. Washed the nastiest brown water you've ever seen out of it. Kept flushing until I got clean water, then poured it full of CLR. Letting it sit now for a bit. This should do the trick. As nasty as that water was, flow couldn't have been very well.

6speedsd · Nov 3, 2012

Put it back together and cranked it up, heater full blast. Started blowing heat before the temp needle even started moving. Before it had to be up to op temp before I got heat. So that definitely helped. Supposed to be high 30's Monday morning so we will see how well it works then.