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Hate to post a stupid thread (Heater core lines)

Nick 6.5

Nick 6.5

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Location
California
like the title says I really didn't want to post this thread. But I'm having issues with my 02 lb7. I tore the truck apart 3 years ago and seem to have lost a couple coolant/heater lines. I did an egr delete. And can't figure out how the hell the lines are ran. I have the single hard line coming out of the t stat that feeds the heater core after the egr delete. But have no idea where the heater core return line goes. Any input (with detailed pics) would be extremely helpful!! I've tried to look at prints and parts layouts but I can't seem to find out.
 
Is there a nipple attached to the raditor, above the big return hose that hooks to the waterpump.
Other wise the heater hose would be hooked to the waterpump, down low on the passenger side of the wehicle but above where the big hose attaches.
 
The only nipple I have is at the very top of the radiator on the passenger side directly above the Trans cooler lines. And I also have 1 line that T off the lower radiator hose.
 
Just went out and looked at My truck, 2000 K3500.
The heater hose is in the top of the radiator. It would be Your call to whichever position to hook the hose to. they both would do the same thing.
The one to the lower radiator hose would provide some draft as that would be the suction side of the cooling system.
 
You cannot compare a duramax to a 6.5l, completely different cooling system routing. I forgot you had a Cali engine. Origanally there was a short tube that came out of the tstat housing, a short hose hooked to it and routed coolant to the egr cooler, then the coolant exited the egr cooler at the rear back by the turbo, and went into the heater core above it in a gmt-800(gmt-400 has the heater core hookup down lower behind the accumulator). The the coolant exited the heater core, hooked up to a metal tube mounted on the passenger side of the engine above the exhaust manifold just behind the FICM, ran around the front of the engine, and the lower radiator hose has a line that comesoff of it just before the water pump that connects to the return tube. GM stopped returning the heater core return to the radiator with the duramax(which was a big mistake imo), and only has the 1/2" tube that goes to the degas bottle for burping air out of the radiator. I don't have any pics of a cali emissionsengine heater hose routing, but if you look at your tstat housing, you should either find a short tube that comesoff of it with a 5/8" hose barb on it, or a 5/8" id hole in the housing where the tube goes. You can use the short tube and run flexible heater hose, just make sure and use the blue silicone hose because of the heat that is in the valley. And also get some 3/8" silicone hose, and redo the coolant hoses for the turbo as the rubber hoses are known to fail as they don't like the heat they're exposed to in that balley with the turbo there.
 
Inwas trying to run the lines like factory duramax routing to eliminate issues of replacing hoses down the line. I do have the 5/8 hole in the t stat housing. I also did find the original egr feeder tube toady with the o ring seal. I understand the tstat steel line feeds the heater core. And my understanding is the small 3/8 nipple on my radiator goes to the smaller line on my coolant tank. But my problem is the return. I do have the line that T off in the lower radiator hose before the water pump but I thought that's went to the larger connector on the coolant tank? I also do not see a metal tube that goes around to the front of the into the engine. There isn't any kind of fittings in the duramax water water pump that MrMarty was talking about? The only other tube I see is off the thermostat bypass that feeds the turbo cooler line. It just seems to me that I'm still missing a line or something. Should I just try to splice a T for another line into the lower radiator hose? So if have 2 lines on the return?
 
I believe I figured it out. I checked the part number on my lower hose and it's match for the 6.5 lower hose with 1 T. Either I messed up or the parts guy did. I just ordered a for sure Dmax lower hose with 2 Ts on it.
 
I need to pay more attention to the original post when I read them.
Your truck is an 02 and so I do not think that any of the information I laid out will apply to Your truck.
I apologize for any confusion.
 
Hope you got it figured out. You have a lot of guys dream truck right there. Mine to. A 400 series truck with a duramax in it would be sweet as a daily driver and tow rig. Keep up the good work and MAKE SURE to post a video of that thing running. Some pictures of the truck would be nice to.
 
MrMarty! No worries at all I appreciate the input either way! It's nice to know you have a community of knowledgeable people that can help you out when your stumped! (Even tho I may have been an idiot on this one. Or the guy a parts plus)
And Jaryd thanks!! This truck is worth no where near what I've put into it tho. I have reciepts for 19k now. It's been a 4 year project almost. And j actually am setting it up for to tow my 30' goose. I'm hoping for 25-26 mpg unloaded with a light foot with the upgrades. This whole build I was following pretty close to the ferminators build with some changes that I felt necessary for my needs. He's been a huge help. And I will post what I have
 
That sounds like it is going to be a very capable unit.
I did not know coolant lines went to the EGR and the turbo too, I have never seen that befor.
 
I HIGHLY doubt you will never see 25-26 actual mpg. The best I have seen has been an lbz running 60-65 in 6th gear with an econ tune on street tires, and that was almost bumping 23. Best I ever got was 22, but I might could have bumped close to 23, but I'm running 3.42 gears, short/light pizza cutter tires, and was running 65. 70 used to get me 21, but with b20, my new Cooper tires, and sac injectors, I can just bump 20 on the interstate(it is SO hard staying out of the go pedal with how it spools and wants to launch with the sac's). Not trying to burst your bubble, just being realistic.
 
MrMarty51 said:
That sounds like it is going to be a very capable unit.
I did not know coolant lines went to the EGR and the turbo too, I have never seen that befor.
Click to expand...
When you run alot of egr flow, you must cool the gasses, otherwise you will heat the intake charge, and counter act the NOx reduction that the egr flow is trying to achieve. And since the turbo is mounted in the valley tucked up in close to the firewall, it is liquid cooled to help keep the heatdown some(and it also greatly reduces turbo cooldown times to reduce oil cooking in the turbo on ahot shutdown).
 
THEFERMANATOR said:
I HIGHLY doubt you will never see 25-26 actual mpg. The best I have seen has been an lbz running 60-65 in 6th gear with an econ tune on street tires, and that was almost bumping 23. Best I ever got was 22, but I might could have bumped close to 23, but I'm running 3.42 gears, short/light pizza cutter tires, and was running 65. 70 used to get me 21, but with b20, my new Cooper tires, and sac injectors, I can just bump 20 on the interstate(it is SO hard staying out of the go pedal with how it spools and wants to launch with the sac's). Not trying to burst your bubble, just being realistic.
Click to expand...
Hey no worries! I'd still be happy with 20. Was just hoping for more haha. And I can't wait to start to drive mine so I can hear the turbo spool haha
 
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