Cold Heat, HIGH Engine Temps
#11
01-22-2013, 08:11 PM
Champion
Agreed with what dh provided.
To add to Sooper, if you don't have a deeeep socket for the Engine Coolant Temp (ECT) Sensor, then you need to remove the alternator to access it. The heater core hose is located right next to it (~1" OD tube).
But I wouldn't venture to this yet until burping is complete.
I ended up having a shop flush my heater core and no problems. If you have leaking inside the passenger floor and/or coolant smell INSIDE the cab, then the heater core MUST be replaced. Hope for just doing a flush which is just disconnecting both inlet/outet and using your garden hose.
As for the blend door failing, the indications is using the temperature control and it not registering. Meaning you set to cold, and while driving you brake, you all of a sudden of heat!! As said the door is not operating b/c of a plastic hinge piece broken.
So you buy this heatertreater part to replace (metal) as he mentioned:
http://www.heatertreater.net/index.html
Here is a video I made on what a PITA to access the screw for the blend door cover.
To add to Sooper, if you don't have a deeeep socket for the Engine Coolant Temp (ECT) Sensor, then you need to remove the alternator to access it. The heater core hose is located right next to it (~1" OD tube).
But I wouldn't venture to this yet until burping is complete.
I ended up having a shop flush my heater core and no problems. If you have leaking inside the passenger floor and/or coolant smell INSIDE the cab, then the heater core MUST be replaced. Hope for just doing a flush which is just disconnecting both inlet/outet and using your garden hose.
As for the blend door failing, the indications is using the temperature control and it not registering. Meaning you set to cold, and while driving you brake, you all of a sudden of heat!! As said the door is not operating b/c of a plastic hinge piece broken.
So you buy this heatertreater part to replace (metal) as he mentioned:
http://www.heatertreater.net/index.html
Here is a video I made on what a PITA to access the screw for the blend door cover.
The burping is an important step, and likely to fix your problem.
Another option, one that I tried once on a whim that fixed a fellow's issue...same as yours...was simple. Replaced the wonky temp sender. It's cheap, and fairly easy to get to behind the alternator. I replaced it and the fluctuating temps stopped.
The loss of heat in the cabin is most likely a clogged heater core, but the blend door operation might be compromised. There is a motor that spins and stops with resistance and as it wears it stops controlling the door itself.
You can test it by getting on the floor and watching the motor / door connection as you change the temp on the dash. Watch it turn and stop as you change the temp. If it keeps spinning and spinning...it needs to be replaced by a metal one...which can be found on Ebay.
The bad news is that if the heater core itself is clogged or even leaking in the case...it needs to be replaced and that requires a complete removal of the dash from the truck, and that is NOT an easy task.
Another option, one that I tried once on a whim that fixed a fellow's issue...same as yours...was simple. Replaced the wonky temp sender. It's cheap, and fairly easy to get to behind the alternator. I replaced it and the fluctuating temps stopped.
The loss of heat in the cabin is most likely a clogged heater core, but the blend door operation might be compromised. There is a motor that spins and stops with resistance and as it wears it stops controlling the door itself.
You can test it by getting on the floor and watching the motor / door connection as you change the temp on the dash. Watch it turn and stop as you change the temp. If it keeps spinning and spinning...it needs to be replaced by a metal one...which can be found on Ebay.
The bad news is that if the heater core itself is clogged or even leaking in the case...it needs to be replaced and that requires a complete removal of the dash from the truck, and that is NOT an easy task.
#12
01-25-2013, 11:06 PM
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To start with, I have searched, and havent been able to find the same issue. But I feel like (maybe more so just hoping) that this is a relatively easy fix and I'm just an idiot.
98 1500, 5.9L with 150k. Just finished the plenum less than 3 months ago. Replaced the T-stat, water pump, belt tensioner, belt...etc
I live in Iowa, and its cold as **** here right now. The temp gauge before would get to about half way to the middle, so 1/4. Im at work right now and not looking at the truck to know what the actual number is.
Now, it runs ALL OVER THE PLACE. For a few days I was thinking it might be the fan clutch. The temp would skyrocket while I was idling, but rarely hit the red. (i think it hit it once) Then when I would start driving it would cool off. Meanwhile, still blowing cold air.
Now its doing basically the same thing, but it will skyrocket when im driving too. Then when i give it some gas, I hear the water sound in my dash, the temp drops back down to the 1/4 mark, and the air turns nice and warm.
Does that make any sense to anyone? I wanted to try and get a video of the temp gauge while I was driving but havent had a chance to do it yet.
I apologize ahead of time if I missed something on here where this is a common issue, or for just being a dumbass. But any help would be appreciated.
Thanks!
98 1500, 5.9L with 150k. Just finished the plenum less than 3 months ago. Replaced the T-stat, water pump, belt tensioner, belt...etc
I live in Iowa, and its cold as **** here right now. The temp gauge before would get to about half way to the middle, so 1/4. Im at work right now and not looking at the truck to know what the actual number is.
Now, it runs ALL OVER THE PLACE. For a few days I was thinking it might be the fan clutch. The temp would skyrocket while I was idling, but rarely hit the red. (i think it hit it once) Then when I would start driving it would cool off. Meanwhile, still blowing cold air.
Now its doing basically the same thing, but it will skyrocket when im driving too. Then when i give it some gas, I hear the water sound in my dash, the temp drops back down to the 1/4 mark, and the air turns nice and warm.
Does that make any sense to anyone? I wanted to try and get a video of the temp gauge while I was driving but havent had a chance to do it yet.
I apologize ahead of time if I missed something on here where this is a common issue, or for just being a dumbass. But any help would be appreciated.
Thanks!
#13
01-26-2013, 04:53 PM
BTW, a trick I use on most of my engine builds...is I drill a trio of 1/8" holes through the brim of the T-stat. These tiny holes not only allow a TINY bit of fluid to flow which speeds up transmission warmup time but it also lets air pockets bleed away and into the radiator where they are bled out of the system.
#14
01-26-2013, 05:56 PM
#15
01-26-2013, 05:59 PM
#16
01-26-2013, 10:45 PM
A lot of air can get trapped in the the heater core...which causes severe loss of heat in the winter. I does sound like you are sucking in air from somewhere.
Is the coolant level dropping as you burp air? Is there coolant under the passenger side carpet?
Does the exhaust smell sweet or have a white smoke to it?
#17
01-27-2013, 03:25 PM
Block test negative for combustion gasses. Negative on the wet carpet. Exhaust is white but not a lot and smells more of gasses then coolant(plenum not fixed yet, waiting for warmer weather). Initial burp coolant drop was significant. Now it just drops maybe an half inch to an inch. That is with lightly reving the engine. If I rev it hard it will spit coolant out, maybe I got a blockage. I have done the flush and back flush with the tee in the heater hose attached to a garden hose. Temp gage rides up on max 260 but doesn't go into red. Might be a bad gage. I have replaced both temp sensors as well, new pump and stat.
#18
01-27-2013, 08:01 PM
#19
01-28-2013, 08:30 AM
I doubt the gauge is bad. When they go bad they read consistently incorrect instead of fluctuating.
I agree with the air bubble but definitely do the heater core back flush, and definitely use a system cleaner designed to dissolve buildup in the heater core that hinders flow. Prestone makes a good one found at chain stores and it's easy to use.
You'll need to burp again. If you're up to it, maybe pull the T-stat...check it in a pot of boiling water with a thermometer, and drill the tiny holes while you have it out. The holes can help a lot with the air bubble problem for temp readings because the air pocket can't sit right under the T-stat anymore and it self bleeds over time as you drive.
