well....I had heat yesterday morning.....500 miles pulling a trailer....an no heat....well a little when I am driving...none when I am parked....thermastat issue? or something more...thank god it's summer...(well almost)

 

Might be your water pump keep an eye on your temp guage

 

overflow was empty.....filled it.....level is still the same.....engine temp running normal...

 

air in the cooling system and lack of coolant will cause poor cabin heat.

and yes, the thermostat might be sticking open or the radiator cap might not be properly pressurizing the system. have you been able to determine where the coolant is leaking from?

 

Sounds like a classic example of low coolant. But don't just check the overflow bottle, because when there is a cooling system leak, the overflow bottle will not give you an accurate reading. The cap will not pull the coolant back in.. because it's 'sucking wind' through the leak.

You can verify this by refilling your cooling system properly. To do that, take a moment and read this post about the proper way to refill your cooling system and be sure the air gets out.

 

I don't know...honestly I have put..well going on 70,000 miles...and I don't recal ever checking the radiator....and with the amount of things that have happened to it....I can't imagine no one has ever checked it.....the truck has never run hot....even when I added coolant to the overflow.....it was only running a smidge hotter than it was before....and that's cause I was pulling a trailer.....nothing is dripping....I am not realy convinced it's a leak....like I said....there are no other symptoms....it seems like it's kind of a fluke thing....I will know more when I look it over better this weekend.....it's a mystery....oh however....my oil was down almost a quart when I went in the the oil change,....that was new...my truck has never realy been low....hmmm.....oh no...she's getting old.....

and for all those people that don't know...it's a 2000 4 door blazer with a little over 110,000 miles...

 

I found my formerly favorite quick lube place only filled the oil up to the ADD mark on the dip stick. They had me thinking I was "loosing" oil also.

 

well it was the first time in almost a year....so I don't think that's the issue either.....lets face it....vehicles loose mre oil as they get older...

 

Keep an eye on the temp gauge. If it does not get to around 200* then you have a thermostat that is stuck in the open position. I recently replaced my thermostat because of a lack of heat and that fixed the problem. I also flushed out the heater core and replaced the radiator cap. I replaced the cap because of mileage on the car and when I bought it. Since caps are not that expensive it was a good time to replace.

To flush out the heater core remove the hoses and attach proper size garden hoses and run water through in both directions until the water runs clear, there may be rust clogging the heater core also causing a loss of heat...

 

correct me if I am wrong...but I don't think my truck has a heater core....didn't they stop putting those things in vehicles a while ago? I am still thinking it's the thermostat....it dosen't ever get that hi...100 is the first number right.....210 is the middle.....it stay half way between the two...but then it's not even remotely close to warm outside....and I noticed the heat gets warmer when I am driving...colder when I am stopped at a light or something....it does make a little heat...just not as warm as it should be....I heard a chirping from the belts this morning too..I think I just need to give the girl a full fledged tune up....look her over...she's do....I will let you all know what I find out...