2nd Gen Non-Engine/Transmission Procedure for changing the Heater Core on my 01?

[hammersley]

I understand it's a nightmare - ... ... has anybody done this?????? Also is there a way to check it before you go into it?? I mean I have the slightest smell of antifreeze but none on the floor... ... I'm thinking that it's just the smallest amount that is sent through the heater air system -- but not enough to get out..... is there a place to "Drill a hole" into the plastic housing to see??????

 

[Thomas]

Issue 46 of the TDR is a must-read. Joe Donnelly wrote an extensive description of the Heater Core Replacement process—it starts on page 12. His sequence of operations and fastener-location chart will likely save you (and me) hours of frustration.

I purchased a new heater core for my 2000 Ram yesterday and will be doing the R&R soon. I too noticed the dreaded slight coolant odor in the cab one evening last week. Some time later, I thought my windshield looked a bit foggy. Turning on the defroster fogged up the windshield. At that point I knew what the problem was.

To convince yourself that the heater core is the problem, pull the heater hoses at the engine and installed a jumper hose. See if the problem goes away. Then re-attach the heater and see if the problem comes back. I was able to see slight wisps of condensed steam coming from defrost and dash vents.

The leaking coolant never made it to the cab floor. It seems to drain via the same path that the water that condenses on the A/C evaporator takes.

 

[georgej]

Quick question guys . . Did the coolant leaking out the AC drainhole leave any kind of trail? I/ve been trying to find a coolant leak so far without success!

 

[Thomas]

After re-connecting the heater (to convince myself that the heater core is defective) I have coolant on the passenger-side upper and lower suspension arms and the outside of the frame, inboard of those suspension arms. There is a bit of coolant under the truck as well.

 

[hammersley]

I have this issue also..................

After re-connecting the heater (to convince myself that the heater core is defective) I have coolant on the passenger-side upper and lower suspension arms and the outside of the frame, inboard of those suspension arms. There is a bit of coolant under the truck as well.

OK - I'm getting stumped on this - Need Help... ... ...



Some background... ... My carpet - on the passenger side and drivers side is wet! Really wet. I had a camo rubber mat installed OVER the carpet - so it wasn't obvious - But I started to smell something that I thought was Antifreeze. NOW don't immediately think - OK it's the dreaded Heater Core..... it may be - but listen to this...



1. The carpet has clear water - not sticky - not colored and doesn't smell like Antifreeze at all... it does smell liek mildew though. .



2. The window doesn't steam up like they do when a heater core really leaks.....



2. Whenever I stop my truck - it leakes water - I guess from the condensor - because it runs down the control arms and onto the ground.....



I don't understand the entire procedure - is it possible water is coming from the AC system and dripping onto the floor???? NOW I have looked and I see no obvious water path - nothing dripping and running a hose for a half four - pulling the carpet back to bare floor led to No Identifiable leak... ... . BUT I didn't have the car running... . Is there a way to check - I mean could water be built up in the HVAC system??? Is there a drain the could be plugged???? HELP... ... ... ...

 

[hammersley]

Help I can't find my issue 46

of the TDR with Joe Donnelly's article on changing the heater core... . And for some reason it must be to late because I can't find him to email him... ... . maybe he has the article... ...

 

[Thomas]

. . . I mean could water be built up in the HVAC system??? Is there a drain the could be plugged???? . . .

You would definitely know if the heater core was leaking.

It sounds to me like the evaporator condensate drain tube isn't doing its job. Bits of leaves & other debris can come in with the fresh air and eventually keep the condensate that freezes on the evaporator from dripping out the drain tube. Take a look at firemanemt's posts in this thread: https://www.turbodieselregister.com/forums/showthread.php?t=77464

Do a search using evaporator+drain+tube and you can read about other problems a few have had with drain.

I'm betting on the leaves and debris clog. You should find the end of the drain tube near the accumulator (the small tank) on the passenger-side firewall in the engine compartment.

Good luck & have fun!

 

[hammersley]

Thanks

Great Post -



what is this that is referred to???



Be sure to check the CHSML before you go through to much trouble with the A/C Drain.



Merrick Cummings Jr



Also - I'm going to look for this hose - any photos of it??????

 

[Thomas]

CHMSL = Center High-Mounted Stop Light. I believe the CHMSL is notorious for being an entry point for water. If the source of your water is not the HVAC afterall, the CHMSL is probably a good place to look.

If you do ever plan to tear the dash apart PM me for a fastener sequence/location/size list. My 2000 should be the same as your 2001.

 

[Glen Pratt]

Just a suggestion. If you do end up doing the heater core you might as well change out the A/C evaporator while you have everything apart. It would suck to have to the same thing over again to replace the evaporator at a later date.

 

[hammersley]

OK - the outlet I founf - on the firewall - letting water out just fine -

BUT the HVAC system itself has moisture on it - sort'a like condensing - but obly on the part to the left of the fan - it is moist and water coming off it. I have never noticed this before. How do I getb at this problem - is there something amiss inside this unit??????

 

[KEnglish]

Mine had the same symptoms. Like others have suggested, extend the condensation drain with 5/8 heater hose with a preformed 90 and a hose clamp. About $5 and it completely cured my problem. Good luck.

 

[hammersley]

How does extending the

hose help???? And am I looking at the right spot - I mean the water comed out a tube that is below the accumulator - Fig 20 section 24:22 of the Shop Manual - on the firewall... ... it sticks out maybe 1/4 inch or so - an it appears to some out parallel to the ground... ... . how woul extending a hose help here - I on't understand or am I at the wrong place???? Water does come out here... . AND why does my HVAC unit get wet on the inside--bottom????

 

[rono]

Is there a way to get a copy of the article from issue 46 on line?

Ron

 

[super38]

Seems there is a lot of confusion as to where the drain tube is, could someone post a photo?





James

 

[hammersley]

That would

be nice to see the photo... ... .

 

[Thomas]

It's not a photo but the attached should get you looking in the right area.

Look for a plastic tube about a half inch ID extending horizontally through the firewall a short distance. It's several inches below the attach point of the clamp at the bottom of the accumulator.

Some have slipped a hose over the tube and extended the hose downward, perhaps for some scavenging effect?

. . . Water does come out here... . AND why does my HVAC unit get wet on the inside--bottom????

As you know, the water that condenses on the evaporator eventually drips off the evaporator and comes out the tube. If the area underneath the evaporator in the plastic HVAC housing had a debris accumulation, some water might be retained beneath the evaporator. With the A/C system running, it's possible this water would freeze, causing water to condense on the outer surface of the housing.

All of the air, along with leaves, dust, pollen & pine needles that comes through the HVAC system passes the evaporator.

 

[hammersley]

It's not a photo but the attached should get you looking in the right area.



Look for a plastic tube about a half inch ID extending horizontally through the firewall a short distance. It's several inches below the attach point of the clamp at the bottom of the accumulator.



Some have slipped a hose over the tube and extended the hose downward, perhaps for some scavenging effect?







As you know, the water that condenses on the evaporator eventually drips off the evaporator and comes out the tube. If the area underneath the evaporator in the plastic HVAC housing had a debris accumulation, some water might be retained beneath the evaporator. With the A/C system running, it's possible this water would freeze, causing water to condense on the outer surface of the housing.



All of the air, along with leaves, dust, pollen & pine needles that comes through the HVAC system passes the evaporator.

Great illustration - but I'm a little dense on the part I underlined above... . can you explain the air passing a bit better... ...

 

[GAmes]

I don't have any leaks, but I do have a cooling problem I believe is caused by 10 years of crud build up in the HVAC. If I go thru Joe's precedures in issue 46 will I be able to clean all the components inside?

 

[Thomas]

The illustration is stolen from your FSM!

The attached shows (from the top) the path of all air coming through the HVAC.

Air enters the system from the cabin or the grill at the base of the windshield, depending on the position of the recirculation door. All of this air passes through the condensor. Trash can enter either way, but most will come in from the outside.

Refrigerant runs through the condensor whenever the HVAC system is running.

The blend door controls what percentage of the conditioned air passes through the heater core.