97 blazer heat blows cold

[97blazr2]

my 97 blazer zr2's heat blows cold air, new tstat heater core is fine, i heard it could be the trap door?? i have tried blocking the radiator but it still blows cold, the temp gauge i can go from cold to warm / warm to cold and it doesnt make the hissing noise that most other cars have. help its freezing here

[BlazerLT]

You sure the heater core is fine?

How do you know for sure?

Could be the blending door is stuck or defective and it is not vacuum controlled.

[97blazr2]

[quote=BlazerLT]You sure the heater core is fine?

How do you know for sure?

Could be the blending door is stuck or defective and it is not vacuum controlled.[/QUO

coolant is full in the radiator and at the proper level in the overflow, i got the car running and used a digital thermometer and tested both hoses at the heater core from under the hood the highest they got to was about 150F if i remember correctly with the heat off, then i turned the heat on and the hose going in stayed at 150 and the out dropped to 100F i believe

[BlazerLT]

What is the temperature on the gauge when the engine is completely warm?

1/2? 1/4?

[97blazr2]

Originally Posted by BlazerLT

What is the temperature on the gauge when the engine is completely warm?

1/2? 1/4?

1 small tick mark over 1/4

[97blazr2]

my girlfriend has a 95 s-10 and the temp is the same as mine and her heat is awesome. when i covered my radiator i only covered it about 1/3 also

[BlazerLT]

Originally Posted by 97blazr2

1 small tick mark over 1/4

Your thermostat needs to be changed.

Temperature should be one tick to the left of 1/2.

[DaveLance]

Why would the temp gauge stay near 210 (one tick to left of 1/2)? Wouldn't the temp drop down once the t-stat opens? I have a 195 degree t-stat in my '96 and when the engine is warming up I can watch the gauge go up to about the 210 mark (which I figure is 195 degrees) and then drop down to about one tick above 1/4. The only time it stayed near 210 was after I plowed through a snowbank and no air was getting to the radiator to cool down the coolant.

[DaveLance]

97blazr2, get your heater core back flushed.

[97blazr2]

i had the dealer change the thermostat when i brought it in to replace the idler arm, so they changed it and it stayed the same so then i changed it myself and still it wont get hot, that was only 2 months ago, the heater core hoses are at the same temp when the heat is off why would i need to flush it?

[DaveLance]

I was having the same problem of no heat even though the engine was running at the proper temp. The heater hoses were also hot to the touch (I don't know what temp). I had the core back flushed and now the heat works great.

[BlazerLT]

Originally Posted by 97blazr2

i had the dealer change the thermostat when i brought it in to replace the idler arm, so they changed it and it stayed the same so then i changed it myself and still it wont get hot, that was only 2 months ago, the heater core hoses are at the same temp when the heat is off why would i need to flush it?

Your engine is not getting up to temperature.

As I said earlier, it should be one or two ticks to the left of half when fully warmed up.

Make sure you use a 192f/195f thermostat when you do the change.

Also, check your blending door and I would have your cooling system flushed and your heater core reverse flushed.

BTW, your blending door is not controlled by vacuum.

[DaveLance]

97blazr2, your t-stat is fine. Do a search for "temp gauge" and check out a thread called "temp gauge" started on 11/19/2004 by davydawg. He included a pic of his gauge at normal operating temperature and everyone agreed that it was correct.

[blazee]

Originally Posted by DaveLance

97blazr2, your t-stat is fine. Do a search for "temp gauge" and check out a thread called "temp gauge" started on 11/19/2004 by davydawg. He included a pic of his gauge at normal operating temperature and everyone agreed that it was correct.

Are you talking about this thread????

http://www.automotiveforums.com/vbul...d.php?t=319304

Appearently you didn't read it! Everyone one said that it was close to theirs, but theirs were higher. And one guy said that when he tested it, that position is about 180 degrees. which is too low.

[blazee]

Originally Posted by ad6kb

looks pretty normal to me for a car that has run long enought for the thermostat to open. Especially if it is cold outside.

Especially if it is cold outside

Originally Posted by cubanlorenzo

that is where my blazer runs at

His is probably stuck. A very common problem.

Originally Posted by BlazayBlazerious

That's exactly where my 98 runs. Actually just brought it to my mechanic's attention because I could swear my old 98 ran one click left of center and the heat was not real warm on the newer one...turns out it was a clogged heater core. He said the thermostat was fine.

The new one is stuck. The old one was good. His mechanic is an idiot.

Originally Posted by DCIV

My Blazer is a 2000 and it runs a little warmer than that just by a couple notches and has from the day I bought it, never goes over the middle line but comes close if I run it really hard.

His is fine.

Originally Posted by BlazerLT

That reading is normal.

Turn your heat dial all the way to dead cold and watch the gauge go up a couple of notches.

BlazerLT is implying that it should be higher.

Originally Posted by molehole

I agree with BlazerLT, between 210-260 is like overheating territory. My Blazer never goes above the tick below 210. MRogers, you may some underlying problem that needs addressing or maybe the gauge is messed up. Just my 2cents

His is fine

Originally Posted by TonyMazz

This was where mine WAS at and I put a CarChip EX on it and measured the coolant sensor...it read 177 - 183.4 tops....which means that the car isn't getting up to temp. So I yanked the thermostat with a ac-delco direct replacement and ow it's just one tick under the 210 mark and coolant sensor reads 194 - 197.5 all the time.

While it was warm enough to go into a closed loop, it's still not up-to-minimum operating temperature...188 min - 206 max.

Self explainatory