You don't find and fix that leak the whole system will ruin because of moisture.

 

If it was only that easy. I have had the dodge at 2 dealers, 1 AC shop and 3 other auto places. NO one has found the leak .

 

If it leaks as bad as you say it should not be a issue to find even for a inexperienced tech.Even SLIGHT leaks eventually show up with dye.If its not under the hood which should be easy to check then its the evaporator.Theres going to be AC oil all over something if it has been leaking a while.If its a MINOR leak.One that will hold a vacumn for 25 minutes plus then you could try RED ANGEL leak stop.(look it up)but its only for very very minor leaks.

 

its got a good leak. I bought a black light, and have been looking for it, its got dye. but i can not seem to find it. But i am no pro, I guess the next option is just buy a new truck

When i go home in three weeks ( 500 miles away) I am going to leave it at the shop that seems to have done the best work on it, and just leave a blank check and say get after it. . .

 

so after reading this thread, i finally added a valve on the pressure line. some people say that the auto trans need that flow from the return line for cooling. but when i look at the line, its already getting flow from the block. so i dont see that being an issue, or back pressure. thoughts?

 

Cylinders 5&6 at the back of the block are what needs that cooling flow. The heater return does go to the tranny cooler.

 

what direction is the water flowing then.... seams to go to the "back" of the engine to me.... and crosses over...... twords the cab. it connects to that pipe right after the "heat protected" 2 inch piece of hose.

 

You're right Ducman. I just went out to look and that heater return joins up with the little piece of foil-covered hose you mentioned and then goes around back of the block to the tranny cooler. At first I thought it was going in there and then back towards the front of the engine, but it ain't so.

So yes, blocking that line could reduce flow to the tranny cooler. I think it will still flow plenty from the other one it tees with coming from the front through that little foil-covered piece. I'd be more worried about flow through the back of the head with the heater bocked.

I ran mine closed for some testing last month and did not see any difference in trans temp. But I have a filter bypass on that line, so not really going affect it that much. I believe flow through the filter line is probably much less, but who knows?

 

Actually I've only had the 1st Gen a bit over three years now and the 3rd gen only a year and a half, so the "years of diesel experience" don't really amount to a hill of beans!

 

2004.5 here... do i need to just plumb this deal to stop flows to the heater core, but install a diverter valve or T in order to maintain the flows and just bypass the heater core? Thoughts?

 

Kjw,

You can do it either way. I haven't add any issues with just blocking off the heater core.

MikeyB

 

The problem is you won't know you had any issues with it until you pull the head and find scored cylinders in the back of the block.

 

Why's that? There are plenty of 5.9L's used in industrial applications that doesn't even have a heater core. Coolant flow in the head is front to rear, so diverting some of the coolant at the midway point wouldn't make a difference. Think it would make the coolant cooler at the rear?

MikeyB

 

ya, i agree with MikeyB.

 

most of our industrial 6bts have a coolant bypass lines that run from the rear to the lower block by water pump inlet. those are 6bts & 4bts in hyster forklifts, water pump applications and case backhoe's. they don't have a heater core but they do have that coolant circulation

I will have to agree that without some sort of water circulation in the rear of the block the inflow of water from the water pump will only cool effectively the front half of the block.

used to be a problem on I6 gasoline engines, even the old desoto and chrysler & dodge hemi's from the late 50's the rear of the engine ran significantly hoter than the front. the solution back then was simple provide a path via a small 1/2 water line from the top rear of the head to the suction side of the water pump and that created the circulation through the engine to help cool the rear of the block. International also employed somehting similar to this on their industrial 345's and 392's. something that was not used on the scouts or small pickups but was used on cranes and loadstars that employed those engines.

So You wouldnt catch me blocking off water to my heater core without having a bypass system to maintain circulation