I have a 03 3500 5.9 diesel that has been down for a few days i think i need a new heat exchanger but for the time being would like to bypass it and need to know exactly how to do this any help would be great thank you

 

you would just run the lines back into each other but prolly burn your trans up

 

Why is it down and why do you think you need a new heat exchanger?

 

my radiator and overflow where full of tranny fluid and trans has no sign of water in it all lines look good so im thinking it must be the heat exchanger

 

Yep, that be the old leaky heat exchanger, alright. No problem bypassing it, maybe a little sluggish in cold weather. Biggest issue is getting the cooling system cleaned out. Run a mild detergent solution in there and change it every day for a week to get rid of the tranny crud. Then flush/rinse it real good before adding antifreeze back in.

 

when bypassing cooler do i just plug outlets on cooler and can i use regular clamps and hose? need more detail thank you

 

It's half inch line so just get a 1/2" hose coupler and see it the innie and outie from the exchanger will reach each other and clamp them up. As far as plugging the old exchanger I guess that depends mostly on if it leaks cooland back the other way after it's disconnected. If not, I wouldn't worry about it, but I suspect it will.

 

you have been a great help thanks i will let you know how everything turns out again thanks

 

Just remember the purpose of the exchanger is to warm the trans in cold weather. The cooler is up front of the radiator. It might start acting funny, shifting late or something like that if you run it without the exhanger in very cold weather. It also acts to share the cooling capacity of the entire system including the engine in hot weather, so keep an eye on the temp gauge. You might see higher than normal engine temps towing heavy without it.

 

Actually, The heat exchanger also helps with the cooling too. I didn't believe it for a long time but it does.

#1 The coolant isn't hot coolant from the engine. It's from the radiator. Which isn't the same temperature as the engine unless your thermostat is WFO (which could happen)

#2 Water to Water heat exchangers transfer heat much faster and more efficiently than water to air. Even though the coolant is hot it pulls a LOT of heat out of the tranny fluid and then the Water to Air cooler in front of the radiator is able to get it cooler yet.

If you pull the Heat exchanger don't be surprised to find that during a long pull your tranny temps get higher and higher and the fluid takes longer to cool down.