2nd Gen Non-Engine/Transmission Another winter w/ no heat!

[Beach]

This is my third winter now with very minimal heat. Either I get frustrated, or don't have time to mess with it. I finaly dug a little today! Heater core line's are both hot, blower work's, thermostat good w/ 190 operating temp. , and now I pulled the blending door servo off and the door does move easily so I guess that wasn't the problem. Last winter I flushed both heater core line's and it flowed fine . I also pulled the blower out today. I reached in to remove any debris, nothing. The one thing that seemed odd was when I put my hand up inside on the fin's, they weren't hot!? Is that the A/C condensor right inside the blower opening? The heater core appear's to maybe be toward's the blending door in the middle. I don't really know what's inside the whole compartment. I'm pretty frustrated and ready to pay for the repair. Any suggestion's on this. Oh yeah, I'd say the temp coming out when I leave the blower on the low setting is around 50deg. Thank's for any help on this never ending battle!

 

[Hammer]

Are you sure the control switch on the dash is not bad?. If the air door and the engine temps are normal then it has to be switch related and not allowing the proper adjustments as you twist it one way or the other... ... . andy

 

[Beach]

Do you mean the temp switch and the blending door operation? I layed under the dash and operated the temp from cold to hot, back and forth and watched the motor turn the shaft on the blending door before I took it apart. It appeared to work fine. Is that what your referring to or is there some thing else I'm missing?

 

[Crash&Burn]

The part of the air condioner in their would be the evaporator, not the condenser:-laf

 

[wcjp]

Have you checked for a vacuum leak? Some of the HVAC controls are vacuum operated. The vacuum Tee feeding the HVAC is about the middle of the truck on the firewall near the hood.

 

[Jim Fulmer]

Another odd issue

I hate mine too in the winter, it take for ever to warm up verses my gasser truck.



Yesterday I notice by accident that if you are running in A/C mode either through the vents or bi-level that you will have heat that you can use long before the water temp gets up. I've had my truck for 6 years and this was the first tiem I noticed this or tried it.



Jim

 

[Beach]

I checked for vaccum leak's tonight, and found none. I added a little coolant and it seemed to give me a little more heat. I can run the blower all the way and it stay's maybe 55-60. It's better than where it was. The blending door didn't seem to be stuck and it moved freely by hand so I reinstalled the servo motorfor it. That has to be the stupidest design ever. Three holes that hold it in place with a tap and two screw's. One of the screw's being in the back where you can barely get to it with a 90 deg. phillip's. Why didn't they put the tab in the back and the two screw's in front where you can get to it..... stupid! Anyway's the test will be tomorrow when it's colder. It's about 40 now so we'll see! Thank's

 

[DLMcpherson]

I had a 94 Diesel, and finally found that there should have been a "poppit" in he water pump by-pass line on the front of the block. (a small finger-size hose about 4-5 inches long) The fitting is screwed into the housing (brass) and the small hose attaches it to the head? i think. This works kinda like a check valve. Before repair, coolant by-passed the thermostat and the engine wouldn't warm up.



fixed my cold butt right up!!:-laf



hope this helps !!

 

[DonFitzwater]

I never get any heat unless I run my engine at a high idle speed. 1500 rpms seems to work very well, even at -40. My last 97 12 valve made very poor heat after a few years and after some cleaning, troubleshooting, cursing and freezing my nads off I replaced the heater core and wammo, I had great heat. I also run my truck with the cold front zipped up when it's 15 degrees or colder out. Engine rpm usually is the fix for low temp output though. Goodluck!!!

 

[KarlC]

Before I'd take it to a shop I'd really flush the heater core out good. Take both heater hoses off and use a garden hose with a nozzle like you'd wash your truck with so you'll get a mix of water and air bubbles. Go easy at first so you don't blow up the core if there's a restriction. The bubbles will help loosen dirt stuck in the core. Flush the water both ways back and forth until it looks clear when you look at what's coming out in a glass. Then blow both ways with air, then more water, then air again. It has to flow really freely. If there's any kind of restriction the water will flow through the bypass or radiator instead of the heater core.



If you can, hook the garden hose to hot water (drain of a water heater) and run hot water through the heater core. Then turn on the key and run the fan with the temp dial all the way up and see if the air comes out hot.

 

[JMetzger]

I have seen a lot of heater cores plug up internilly. Water will still flow through the in & out but will not pas through the core. Happens a lot if the cooling system is not kept clean

 

[Jim Fulmer]

Q: Will your trucks pump out heat instantly in A/C mode with the thermo turned up to max heat. Mine did this the other day but I don't think I have ever tried it before.



Jim

 

[Beach]

My heater core is real hot to the touch on top where the lines go in. The black casing around it down by the floor is really warm to. I wonder if it's plugged with debris. I reached in when I had the blower out but I thinkI was feeling the evaporator not the core. Is there a way to access the core from a vent or the top ofthe dash. Maybe I could put a small brush in and loosen the debris and then use a shop vac with a small hose to clean it? I'm up to trying anything. I'll try flushin the core again really good. Thank's guy's for any and all help. I appreciate it!

 

[RAlberg]

Did you take the thermostat out? Mine was a 98, a corner of the rubber gasket was loose and stuck in the thermostat so it wouldn't operate properly? I don't know if yours even has a gasket, just another idea.

Bob

 

[Mudinchev]

Dont feel alone I am having heater issues my self, I think mine is a vacume problem though. It has been 2-3 years since I replaced mine, but what a PITA that was. If memory serves me right you can get to the top of the core but you have to remove the dash to do it. It does sound like out side of the core might be plugged, I cant remember how much room there in there to clean it but if your creative I think you can. IF YOU replace it Napa's core has swivels on the inlet and outlet lines to make installing it a lot easier. To use a factory core you will have to dismantle your AC system to remove the whole air box. I ended up crimping and bending the lines on the bad factory one to remove it and was able to pull the air box back far enough to swivel the lines on the Napa core to snake it back in the hole and leave the AC unit intact. FYI unless you already know this, there is one nut behind the computer mounted to the fire wall that needs to be removed before you can pull the air box away from the inside to gain access. Seems to me just finding all the fasteners was a PITA.

 

[CCahill]

Beach,

I'm having the same problem as you... I'll be watching the thread to see what you find... . good luck !!!

 

[Beach]

For those of you that have no heat like I did, after three winter's, or 2. 5 winter's, I now have heat. I found a guy thru a buddy that replaced my heater core, which was partially plugged and replaced my evaporator which was leaking also. I decided to pay to have it done since I would not have had the patience for pulling my dash. I just picked up my truck yesterday and can now turn my heat down because it get's too hot. Sound's dumb but it's like a new vehicle again and now I'm not cold anymore. I think I got lucky, this guy did everything for $700! I've heard it can cost $1,000-$1,300. I did'nt think my heater core was plugged but I guess I was wrong. Good luck to those without heat and look around for a good price if you decide to pay! Thank's for all help on this issue I had. Now I need to fix my rusty door's! Thank's again!

 

[JWine]

my truck has had the same luke warm for 2 winters I flushed it with a garden hose, water ran clear and free still no heat, took it to a shop for rearend work,had them flush heater core only with a cleaning chemical works really well now. Mechanic said some cores get blocked and the collant goes in and right backout not flow the length of the core

 

[hilda]

This is my third winter now with very minimal heat. Either I get frustrated, or don't have time to mess with it. I finaly dug a little today! Heater core line's are both hot, blower work's, thermostat good w/ 190 operating temp. , and now I pulled the blending door servo off and the door does move easily so I guess that wasn't the problem. Last winter I flushed both heater core line's and it flowed fine . I also pulled the blower out today. I reached in to remove any debris, nothing. The one thing that seemed odd was when I put my hand up inside on the fin's, they weren't hot!? Is that the A/C condensor right inside the blower opening? The heater core appear's to maybe be toward's the blending door in the middle. I don't really know what's inside the whole compartment. I'm pretty frustrated and ready to pay for the repair. Any suggestion's on this. Oh yeah, I'd say the temp coming out when I leave the blower on the low setting is around 50deg. Thank's for any help on this never ending battle!

Beach





My money is on the blend door. I fixed mine about 6months ago. A quick way to tell Remove the blend door motor and turn the door one way or the other drive around for awhile. One direction will Give you heat the other AC. Check my earlier posting for the thread. You should have 12 volts to the blue wire at the blend motor plug.





Hilda