No issues with your heater core gunking up? If not, I'm going to get the parts very very soon... 101+ is B.S! and your future south than me

 

I do open the valve mid summer just to run some fresh coolant through the core. HOAT coolant doesn't seem to gunk up like the OAT type coolants.

MikeyB

 

the number six cylinder heating up has me unhappy with blocking the one hose, i am thinking your setup is the true answer, for someone who intends to keep their truck forever. (not get wrapped up in EPA stuff in a new truck)

my wife don't mind the passenger side being hot, but got family borrowing the truck this week, and the grand-babies are hot in the back.

 

My 2003 which has had updated hose/valve and another hose showing dye replaced and looked at numerous times since new. Last repair was summer before last. Chrysler still was warranting it as I kept a OPEN file on it from 2003 about ac. Last summer it was about a 6 to 10 degree difference from left to right. I let it be. This summer it is was a 10 to 12 degree difference left to right. So the other day I did a real scientific thing. I bought ONE can of freon with a hose already attached. I ran fast idle up with a stick to 2000 rpm. I shook ac can and had wife watch my two ac thermometer's. One in left vent,one in right. I added freon until both sides evened out at 40 degrees on recirc. Turned freon can off then. Its COLD and works great. If thats ALL I have to do once a summer then so be it. Lots cheaper and lots less headache then doing a bunch of ac/heater mods. By the way my 2003 only has 39,000 miles.

 

didja omit the first digit? 139k or 239k? get that thing out & about!

what diff does running up the idle do?

my guy today was done with mine, ready to disconnect, it took about half a can.

he cycled it off & on to equalize pressure across the system, it took a bit more,


then I hit the high idle, he turned the AC on, and it took the rest of the can

 

High idle to keep fan pulling air through the condenser and equalize pressures. Takes freon more readily. Only 39k. I hate driving a dually unless I gotta. Only times it goes out is with a trailer hooked. It will get used more as wife is now showing reining horses. Just bought a 3 horse with 10 foot LQ trailer.

 

Good to see you back. My truck took one can this year also. It is very cold now. New trailer is going to work that truck good....

 

Back just for that one thread. I'm on the Vette forum a lot now. LOL. Part of my bucket list. Ac in this will freeze you out! Feels like same volume as in the dually.Just a fraction of the area to cool.

 

Don't blame ya a bit....LOL

 

Must be nice... I'm going for the Z06...

I'm gonna take the out hose from the head and twist it to be the in hose... take one hose out completely. We'll see how it works on mine, and what is different on the wife's hemi... I might just be buying two 'U' shaped copper pieces to round them off...

 

I got a cable driven valve and a choke cable. Us poor ol' yankees have weird temperatures up here.

One of these days I'll cut it in.

That's 3/4 hose isn't it?

 

It's been a while since anyone has reported on this post. After reading all 31 pages, I thought it would be helpful if some of the original posters,or someone who has done this mod for some years now could report on the pros and cons!


I also notice that someone used 1/2" shut off valves with 5/8 nipples instead of 3/4" shutoff valves with 5/8 nipples. The 1/2" valves definitely take up less space in the engine compartment and are cheaper to boot. Now, the question is......Do the 1/2" valves going into 5/8" nipples restrict the flow enough to matter?

 

My installation looks exactly like the one in the photo you posted. After reading some of the posts from some of our more knowledgeable members (after I did the mod), however, I have elected not to shut off the flow to the heater core at any time. The flow through the heater core from the head is what cools that far rear portion of the head. Shutting off that flow eliminates the flow of coolant there and may cause undue heat stress on that end of the head and the components in it. Apparently there was some trouble with this in earlier models of the Cummins 5.9, so that rear coolant port was placed at the back of the head in that location to increase coolant flow there and alleviate the problem.

This used to be a common mod for pickups, back when they had no A/C, to stop the flow of coolant to the heater core in the summer time, to keep the cab cooler. Maybe it wasn't such a good idea then either.

Just going by memory, since I did the mod several years ago, but I think I got the essentials right on why I don't use it.

 

I'll second that. I did this mod a long time ago and I haven't turned that valve in years. Back when I first installed it I tried it open and closed and it didn't seem to make much of a difference to me (or my thermometer in the vent). I think a properly functioning AC system is worth more than what small benefit this mod may provide.

 

When I did the mod years ago I noticed a several degree variance with the valve closed. But without a controlled environment it's hard to correlate.

Personally it's a worthwhile mod for the hot south. Nice to be cruising through Texas on a hot summer day with the cab temperatures in the 60's.