what is up with it automatically putting on the AC when we hit AUTO??? what if its winter and we dont want the AC on when we have the TEMP set to 90???

any fixes or do you have to hit the AC button after hitting auto for the heat to work.

 

wayne you will order and replace it yourself? or just tell the dealership to replace it??

 

^ either or thermostats shouldnt be too hard to do on any car..

Okey.. AUTO = The climate control system will try to get the cab to that temp.
When you hit A/C you activate air conditioning (without it you'll get outside air) However, as long as in the climate control temperature is higher then ambient air temperature then it'll be on "heater mode".. so weather or now you have A/C on or off if the climate control temp is greater then ambient air then you get heater.

Thermostat problem = Hard to warm up engine or engine overheating (over heating is sometimes confused with a thermostat problem with radiator cap fails)
Heater Core Valve = When heater is on but no hot air or only warm air enters the cab

 

I'm going to replace it myself You can get a thermostat pretty cheap (~$20), so no sense in paying someone else to do it.

 

where did you buy it from

 

RockAuto, Stant part #14667. $18 and some change.

 

I had the same problem...Check your coolant level

 

Sorry for the late response, I've been out of town and busy for the past few weeks.

I changed the thermostat, but the problem persists. After I first changed it I drove around the neighborhood and the temperature gauge went up dramatically and stayed up close to the H, but the heat worked. I brought it back to the house, let it sit for a while then drove around the neighborhood some more. The temperature gauge would go up, then back down to the center, then up, then back down and would repeat this usually while accelerating or going up hills. The heat at this point began doing the same thing as it had before: not working under ~40mph.

I brought it back a 2nd time and checked the coolant levels. While running the engine, I poured some coolant into the radiator, and each time it would bubble and the coolant would suck down to where I couldn't see it any more. I kept pouring coolant in and waiting for the bubbles, then watching it settle down...and did this 4 or 5 times. I drove it around again and the heat worked at lower speeds, but still blew out relatively cool air while idle (though it was warmer than before).

I've been driving it for about a week now, and the situation is exactly the same as it was before I changed the thermostat: no heat under ~40mph. However, I did notice that when I go over certain hills, the temperature gauge climbs to about 3/4th the way up the scale, stays there for a little while, then falls back down to the center. It only does this on mildly sloped hills, and while accelerating up/down them.

A friend of mine said that it might be bubbles in the coolant lines, or that a hose might be collapsing somewhere. He was convinced it was a thermostat problem as I described the situation, until I told him that I had replaced it, haha.

 

Just FYI.

My heater blows hot air no matter if I sit idle or if I'm at speed. I'm pretty sure of this because I was sitting in the park n ride waiting for my bus for about 10 min and it was nice and toasty. It was 31F outside.

Here's a question. When you're stationary. Have you tried to bring the revs up to about 1500-2000 rpm while in neutral? I'm not sure if the water pump on our VQ is electrical or mechanical. That should help by eliminating variables.

 

I haven't tried that, but I have tried driving around in a lower gear so the RPMs sit around 2,000, even though I'm going only going ~20mph.

I'll bring it to 2k while in neutral and leave it there for a while, and I'll let you know if I get any change in the heat.

 

I am having the exact same issue, and still trying to figure this out also

 

I revved the engine in neutral up to ~2k and the heat started to kick in. So, I began driving around in a lower gear so that my RPMs stayed around 2-2.5k, and the heat seemed to work just fine regardless of the speed.

However, at one point I went down a slight hill and the heat stopped altogether, no matter how fast/slow I went. It later kicked back in but I don't know under what circumstances, exactly.

 

bump...

I'm having the exact same problem. KEEP us updated.