How's this for a heating issue??

[Fastbird]

I've noticed this the past couple of weeks with our 00 LS. The heat works, but only when you're physically pushing the gas pedal or if you've got it maxed out. If you let off the pedal the air goes cool. I have a feeling it's a vacuum related issue, but was wondering if anyone was familiar.

 

[Rastlin]

Re: heating problem

Yeah, I just noticed the same exact thing in my 2000 LS... I have the V6 with the 5-speed manual and the heating will only work if you are running the engine at at least 2700 or so RPMs... preferebly at 3000+. I have just posted a thread to see if anyone knows a fix for it. If you find something out please let me know. (I will do the same).

 

[beaups]

sounds like air in line or coolant isn't flowing at low rpm's. my guess is either:

1.) Thermostat bad (stuck mostly closed, higher rpms allowing some flow to get through)

2.) air in lines somewhere

3.) pump failing and no flow at low rpm's

 

[2001LS8Sport]

sounds like air in line or coolant isn't flowing at low rpm's. my guess is either:

1.) Thermostat bad (stuck mostly closed, higher rpms allowing some flow to get through)

2.) air in lines somewhere

3.) pump failing and no flow at low rpm's

I'm guessing you would have engine cooling issues...or at least notice something out of the norm if this were the case. I think you're on track with your vacuum concern. When you have your foot in it, there is no vacuum and that may allow a door to open or close. Finding it could be a real bitch though....

 

[Rastlin]

Re: heating problem

I just got mine to work!!! check the coolant levels in both tanks. If they are fine take it in and flush the system. Hopfully that will fix it... (it did for mine ) ... if it wont... I would check the Auxilirary Coolant pump... or thermostat.
The low coolant level makes sence since at the higher RPMs you are rasing the pressure and the level goes up to give you some flow thorugh the heating core.
Good Luck!