Heater seems to not be as hot as it should

[TB]

Out of all the trucks/cars i've had, it seems that the heater in my 01 XLS doesn't want to get as hot as I think it should.

Also, it may just be in my head, but it seems like if you're driving, the heater will blow warmer air. When you come to a stop and just sit there, it gets cooler. Not cold, but just not as warm.

Is there anything I should be checking? The truck runs fine and engine doesn't run hot or cold.

Could it just be that i'm not used to an SUV and that there is more cabin to heat?

 

[gijoecam]

Stopped at idle, the water pump on the engine isn't moving as much coolant through the heater core, and the engine isn't producing as much heat as it is when you are accelerating or maintaining speed. It's not uncommon for the temp at the ducts to be a little bit lower at idle.

Now, if it's actually getting cool, I'd be looking to see if the heater bypass valve is opening all the way... That could obstruct the coolant flow to the heater core and cause a similar condition.

-Joe

 

[TB]

Forgive my ignorance, but where might I locate this bypass? Will I see it if I open the hood?

Thank you.

 

[KPT]

Its on the left side of the engine as you're looking at it. Follow the two hoses coming out of the heater core.

 

[TB]

Its on the left side of the engine as you're looking at it. Follow the two hoses coming out of the heater core.

Thank you! That was my plan.....but i'm more of a suspension figure-er-outter than under hood person.

 

[Hitchhikingmike]

Could also be your thermostat? But if your thermostat was staying open then you engine would be running cooler and you would probably see it on the gauge.

 

[TB]

Could also be your thermostat? But if your thermostat was staying open then you engine would be running cooler and you would probably see it on the gauge.

I figured the OE gauge was just a "dummy gauge" and just read either ON or OFF.

FWIW, the needle goes just up to the front of the symbol...almost or barely touching it.

 

[KPT]

FWIW, the needle goes just up to the front of the symbol...almost or barely touching it.

That's the problem. Replace the t-stat. The only dummy gauge is the oil pressure.

Edit: I may have read that wrong. The temp gauge should be about in the middle when the engine is warm.

 

[TB]

Sounds like a cheap fix and I was going to replace it anyway when I did a flush. You guys are much appreciated!

The needle certainly isn't in the middle like on my Mustang.

 

[chapsdeva]

It sounds definitely like your thermostat. Mine was doing the same thing as far as only having warm air and the guage barely getting off cold. Replaced the stat and now I have HEAT!!!!!

PS..You are like me...Have and Explorer AND a Mustang (07 GT!!

 

[TB]

It sounds definitely like your thermostat. Mine was doing the same thing as far as only having warm air and the guage barely getting off cold. Replaced the stat and now I have HEAT!!!!!

PS..You are like me...Have and Explorer AND a Mustang (07 GT!!

Hope thats it. However, after browsing around it looks like thermostats are 15$ to 40$! Damn!

While i've got you guys here, is there any benefit to going with a 180 degree vs. the OE 195?

I like cars that "everybody has". Makes diagnosing problems alot more easy!

 

[96eb96]

Hope thats it. However, after browsing around it looks like thermostats are 15$ to 40$! Damn!

While i've got you guys here, is there any benefit to going with a 180 degree vs. the OE 195?

I like cars that "everybody has". Makes diagnosing problems alot more easy!

I would go with the OE, especially if you want hot heat. It also helps burn off all the moisture in the oil. Computer cars work better with temps in the 190s.

 

[TB]

Thank you again, and will do!

 

[Hitchhikingmike]

That's the problem. Replace the t-stat. The only dummy gauge is the oil pressure.

Edit: I may have read that wrong. The temp gauge should be about in the middle when the engine is warm.

Yes the engine temperature gauge is not a dummy gauge and is a REAL gauge. If your thermostat is functionally correctly, the needle should be spot in the middle!

 

[TB]

Yes the engine temperature gauge is not a dummy gauge and is a REAL gauge. If your thermostat is functionally correctly, the needle should be spot in the middle!

This remove/install looks fairly straight forward after popping the hood. My plan is to pick up the 'stat on the way home from work and let the truck sit 'till the weekend. Then i'll clamp the upper rad. hose with my big C-clamp and some pieces of wood to keep the spillage at minimum, then R/R the old and in with the new.

It's supposed to be back up in the high 50's/low 60's by Friday....so the icicles hangin' from my nose won't effect the job. It was 10 degrees last night.

 

[TB]

Well, I got anxious to have heat again so I picked up the new Duralast OE 195 thermostat and installed it a few hours ago.

It's the same exact problem. The needle just goes up to the first of the symbol and stays there while blowing only VERY mildly warm air from the vents. However, if you hold the rev's at like 3500-4000 rpms, you can easily feel alot more heat come out of the vents. Still not as warm as it should be in my opinion, but it does get noticeably warmer.

I can turn the hot/cold dial and it gets real cold when turned on the cold side, then goes warmer(like maybe room temperature)when turned all the way in the red.

The heater hose going into the cabin is VERY hot, but I have no idea if this means anything or not.

Is there anything else it could be or sounds like?

 

[waxtrax]

It could be the blend door malfunctioning and not closing all the way. There is a sticky on fixing blend door issues here:

http://www.explorerforum.com/forums/showthread.php?t=183742

I would of course verify the problem as a blend door issue before doing the quick fix. Try and inspect the issue with the blend door before you start cutting away at the box. It can be difficult to get in and look but if you remove the blower motor you may be able to visually inspect the function of the blend door to see if it is a pin missing as one of the posts suggests.

Good Luck!

 

[TB]

I've tried operating the cold/hot knob, and it works. It'll get real cold if you turn it to the cold side and you can hear it moving when you turn it back to the hot side.

The more I think of it, the more I think it is that HCV. It uses vacuum and when I hold the truck at 3,000+rpms, it will get hotter. Gotta be some connection there.

 

[corkey]

i had the same problem with my Ex it was kind of hot when running at at bit higher of rpms and would cool off too much when going slow,, i checked the heater contol valve and it worked okay, and than changed the thermostat too, still not hot enuff, , so , i took the hoses off of the heater control valve and flushed the systm back thru the hoses, both ways,, till the water i was using came out,,,i even took off all the rad hoses and made sure i flushed that too, and than flushed the heater core, both ways,, in both hoses,, i than put all the system back together,, and filled with new coolant that tested to -45,with a hydrometer , and there it was , guage went up the to middle of the range ,instead of just moving up a bit, and now the heat is almost too hot,, lol, might have been just the old coolant , or maybe blockages in the system i flushed out,,

 

[TB]

i had the same problem with my Ex it was kind of hot when running at at bit higher of rpms and would cool off too much when going slow,, i checked the heater contol valve and it worked okay, and than changed the thermostat too, still not hot enuff, , so , i took the hoses off of the heater control valve and flushed the systm back thru the hoses, both ways,, till the water i was using came out,,,i even took off all the rad hoses and made sure i flushed that too, and than flushed the heater core, both ways,, in both hoses,, i than put all the system back together,, and filled with new coolant that tested to -45,with a hydrometer , and there it was , guage went up the to middle of the range ,instead of just moving up a bit, and now the heat is almost too hot,, lol, might have been just the old coolant , or maybe blockages in the system i flushed out,,

Crap...sounds like some work, but i'll try it.

Thank you very much for the reply!