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Good Evening Everyone,

 

I'm new to the site but have been reading up on some great articles and opinions for some time now.  I'm in the process of updating and replacing the heater core and AC guts under the dash, along with a new LMC dash top (yeah i know, everyone's wallet just cringed a little).  For all but a short time, I know how its been taken care of since new.  So, i'm willing to replace whats needed and upgrade what should be.  The AC has been leaking in there for some time and i figured a new heater core is just common sense when everything is apart.  My questions are, has anyone needed to replace the blend doors due to breakage (age, not mishaps with stuff getting in the heater box), or thought it a good idea to replace the plastic parts with metal or aluminum?  I know the blend door motor connector is a big one, but what about the other components?  I'm not looking to pick winners or losers of suppliers but Blend Door USA seems to offer a well made kit for the second gens.  At $325, its not cheap but may save pulling the dash later on.  I'm having it done (time and ability constraints) but I know the factory foam will be brittle and dirty at the least.  I say this as I haven't seem them out just yet but foam bits are blowing out of the vent doors.

 

This is the big project for now and i'd like it to be a "one and done" job.  Any thoughts or experience is a great help!!  I know 3rd gens seem to have this trouble worse, but i would imagine a rig almost 20 years old can be expected to need this attention at some point.

 

The next thing is possibly a fuel pressure gauge to see how my dealer conversion lift pump is doing......may not want to know!! :thud:

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I did mine including an LMC dash pad replacement about 7 years ago. The only Hvac hard parts I replaced was the connector from the blend door to the motor. Also the evaporator and heater core. I also replaced the foam with like replacements from the hardware store. Still working fine. I think you would have to see what you see when it's apart.

 

If you have the in tank pump get a gauge now. It may hold a year or more or fail tomorrow. 

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I just places an order for gauges for a gent in Ontario. @mr.obvious.

 

Going to be installing ISSPro EV2 gauges (Boost, Pyro, and EGT). He's also running a intank fuel pump. :duh: We both know the fuel pressure is sub-par with a intank lift pump.

 

As for dash you can extend the life of the plastic by using Armor-All. The trick is to wash the plastics all off and the spray the Armor-All on and leave it cook in the sun. It will change from whitish to clear shine. This keeps some of the oils in the plastic for a bit longer. Mine is cracking but I'm holding it at bay for now. Eventually I'll need to do a dash top replacement like @dripley has. 

 

As for the HVAC system I've replaced the evaporator and heater core once. Blend door is still fine. Then vacuum motors still working fine. A/C works good. The heater works awesome even in subzero. 

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Thanks!!  Yeah any replaceable seals, gaskets and foam is a good idea.  I’ve seen foam kits for the OEM hvac doors, may be an opinion but need to see what i’m working with first i reckon.

 

The dash almost made it 14 years before any cracking, it only got bad in the last year or so but no holes, just a couple of long cracks by the windshield.  Thought about protectants and put some on awhile back, but a towel lived on the dash for years. 

 

I’ve read the horror stories of the in-tank carter conversion pump, this one has been in since 2004.  I drive it like a Mack so WOT isn’t often, maybe this has helped?  Spoke to a gentleman i know with 2 second gens, a 12 valve and a 24 valve.   Both have around 270,000 miles and mostly open road and farm duty.  The 24 valve is still on the factory vp44 and block mounted lift pump (don’t know if replaced).  I guess some people get lucky?  Knowing my luck, once i know the psi, she’ll throw a dreaded code :cry:   

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The foam kit is not a bad idea. The oe stuff has got to be shot. 

 

My dash made it 11 years before a hole started. Mine sits in the sun pretty constant.

 

I had the intank pump also. Worked good for about a year before low pressure started causing problems. My oe vp died at 75k, the next I replace at 217k and the one I currently have is at 257k and still going strong. At 474k the truck runs pretty darn good in my opinion.

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13 hours ago, Mopar1973Man said:

I just places an order for gauges for a gent in Ontario. @mr.obvious.

 

Going to be installing ISSPro EV2 gauges (Boost, Pyro, and EGT). He's also running a intank fuel pump. :duh: We both know the fuel pressure is sub-par with a intank lift pump.

 

As for dash you can extend the life of the plastic by using Armor-All. The trick is to wash the plastics all off and the spray the Armor-All on and leave it cook in the sun. It will change from whitish to clear shine. This keeps some of the oils in the plastic for a bit longer. Mine is cracking but I'm holding it at bay for now. Eventually I'll need to do a dash top replacement like @dripley has. 

 

As for the HVAC system I've replaced the evaporator and heater core once. Blend door is still fine. Then vacuum motors still working fine. A/C works good. The heater works awesome even in subzero. 

the statement about armor all is somewhat funny to me, every dirrty never to be wiped dash that i have seen is in perfect condition, every dash i see that some tries to care for has cracked...just how it is.

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Mine went 7 years ago and it saw little armor all. My truck sits on dusty job sites jobsites constantly. The armor all seemed to be a dust magnet after using it so I stopped for the most part. I just use a wet rag to get the dust every 4 weeks or so. Maybe I did not let the dust get thick enough to bock the sun.:shrug:

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Not the UVs that kills the dash. Its the out right surface temperature that is cooking the oils out of the plastic. Then just takes vibration to crack the plastic.

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It seems to depend a bit on how the truck has been maintained, operated and stored. I see some guys open the HVAC up and it is packed with trash and all the foam is deteriorated.  I literally just finished replacing my evaporator heater core and all doors with the blend door kit..  Only reason for the excursion was to finally address a slow refrigerant leak that I could never locate via dye and UV light (sniffer found the evap at fault right away)... that and a temp probe sleeve fell into the system and was stuck in my mode door so I always had some air going to the floor.  My truck is a 98.5.  273k miles on it, single owner, and is generally garaged.  My evaporator was spotless except for one corner, and maybe a quarter inch along the bottom.  All the doors were perfect except for the reculate door foam facing the exterior.  I was quite shocked it was in such good condition.  Blend door is really nice stuff, no issues with it.  Had I known my system was in good shape I would have left it alone.  I don't know that the 2nd gens are so prone to damaged doors or broken blend door collars, but I don't surf the forums much anymore either.  I recommend using an OEM heater core.  Seven or so years ago I replaced my original with one of the parts store aluminium jobs.  Heat never felt the same after that.  Picked mine up off Amazon for around $152.

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On 7/8/2019 at 9:03 PM, Mopar1973Man said:

As for dash you can extend the life of the plastic by using Armor-All. The trick is to wash the plastics all off and the spray the Armor-All on and leave it cook in the sun. It will change from whitish to clear shine. This keeps some of the oils in the plastic for a bit longer.

Funny you say this....   When searching about ABS plastic repairs, some of the auto restoration sites said that 'Armor-All' accelerated the problem.  Remember that 'Aero 303' was one of the recommend products to use every 30 day to protect the plastic.   Agree that 200F+ temp on the dash does contribute to the problem but also UV exposure.    Have seen plastic not in direct sun become brittle.  

 

Bob G.

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On 7/12/2019 at 10:36 AM, JD435 said:

When searching about ABS plastic repairs, some of the auto restoration sites said that 'Armor-All' accelerated the problem.

 

I personally consider that old wise tale...

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