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Cooling Problems on my 2007 2500 LBZ

Marauderer

Marauderer

Grumpy Old Cur***geon
Messages
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127
Location
Powder Springs, GA
It started early last year whenever ambient got over 80*F coolant temps start really going up while towing a 10K load.

So, what I have done to date is flush the radiator, replaced the coolant, added water wetter, replaced the standard thermostats with the lower temp ones ( I used Mishimoto's) and am still having problems. I have also vented it multiple times. The radiator is the original and is coming up on 10 yrs old. I know Mike has flushed his as have several others on the forum with success.

I am thinking of ponying up for the Mishimoto radiator, hoses, and a Merchants water pump and be done with it. The truck only has 130K mi. on it.

Any suggestions or positive comments would greatly be appreciated.
 
Did you pull the radiator when you flushed it and thoroughly clean the stack Barry?
I'm about ready to do that on mine and have all new hoses ready. Glad to see you back around
 
I did not pull the radiator. I drained it, refilled with flush and ran it for 100 mi, drained the flush, clear water twice running about a hour each time, then fresh AF and fill. I worry about the plastic radiator cracking as they seem to be prone to doing that after 5-7 yrs.
 
Put ac delco stats back in it unless you like wasting fuel and sending it out your tailpipe. AVOID THE MISHIMOTO RADIATORS AT ALL COSTS! There was a post in the ladt week or so about this, but they have been failing left and right. There made overseas, shipped to the states, mishimoto marks them up to $700+(the factory in china that builds them was selling some on ebay and amazon for $135-200), but they do offer the lifetime warranty on them. You can do the merchants pump, but in all honesty the plastic impeller pumps haven't given much trouble with impellers spinning.

Do the basic repairs and maintence a 5+ year old truck needs. Pull the radiator out and clean the cooling fins out, pull the intercooler out and clean it out, clean the condenser and trans cooler while the stack is apart. New ac delco stats. New fan clutch(hayden 2886 or kennedy). PUT THE INNER FAN SHROUD BACK IN! Yes many used to say it wasn't needed, but this has been proven wrong by several now that it is needed. Fill it with a 50/50 mix distilled water and quality dex cool coolant.

My bet is your stack is plugged. With dexcool I've rarely seen the cooling system get plugged up, even 10 year old trucks with 250k miles on the dexcool still are normally clean inside. The stack gets plugged up easily though, and is often overlooked.
 
Marauderer said:
I did not pull the radiator. I drained it, refilled with flush and ran it for 100 mi, drained the flush, clear water twice running about a hour each time, then fresh AF and fill. I worry about the plastic radiator cracking as they seem to be prone to doing that after 5-7 yrs.
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You RARELY hear of the duramax radiators failing. With the way they mount to the intercooler, they don't get flexxed, and seem to last. Flushi g the cooling system I bet did nothing other than flush out the brown embitterment that falls out over time. I bet the flush looked nasty, but there was probably nothing plugging anything. The cooling stack is probably 75% of the cooling issues.
 
Stack is a reference to the radiator, condenser, and transmission coolers stacked together. Can't get them clean in place.
 
Got it!! I will do it as soon as I get home. We are in Fort Worth, TX and will get home Saturday afternoon. I should have it done sometime next week. Lots of YouTube and other threads on doing it. I am excited now!!
 
Sorry Ferm,the new dexcool is still dropping minerals out of suspension. Just helped a friend flush his 2012 this morning. He has never taken it anywhere except the dealership, until telling me what they were going to charge to flush it for him. We ran to oriellys and did it in the front yard. No where near the psyhotic nightmare mud of dexcool of yesteryear- but I will still throw away any given to me for free. 98,000 on his truck btw. Unless there is gaskets or something known to come apart making a sludge in the dmax?

To be fair, I am enjoying a free meatball samich for it- so maybe not all bad!
 
Marauderer said:
Got it!! I will do it as soon as I get home. We are in Fort Worth, TX and will get home Saturday afternoon. I should have it done sometime next week. Lots of YouTube and other threads on doing it. I am excited now!!
Click to expand...
Yeah, I was just watching a YouTube vid (Finnegans Garage, Mike Finnegan from Roadkill). He bought an 06 LBZ Dually and it was getting hot, he flushed crap out of the stack and it fixed his issue. I really need to clean ours, it's never been apart and our truck sees all kinds of shit that'd plug up a radiator...
 
Therm, I have always kept the fan shroud installed as I understand the increased efficiency you get having it in. I am also going to replace the serpentine belt and the idler pulleys. I know all belts and pulleys are not the same. Recommendations??
 
I've had great luck with gates belts. Used to buy them at carquest because of the lifetime warranty, but advance bought them and is closing em all down. As to idlers, I either buy a quality brand, but I've been known to do nust the bearing if it's a metal idler.

As to dex-cool and mineral fall out, I have yet to see it in a duramax. I've worked on em 10+ years old with the factory dexcool in them, and the coolant looked good enough to put back in still. I just changedmine because it was 7 years old, and what came out looked as good as what I put back in it. My neighbor's 03 1500 with a 4.8l still has the factory fill in it. He's cheap and said he won't change it until it looks like it needs it. Not a trace of anything anywhere inside his degas bottle, just orange dex-cool. My grandparents lexus is the same. It's a 03 and came factory filled with dex-cool. Still looks new, and my grand father refuses to change clean anti-freeze. Everybody curses dex-cool in GM's, but Toyota has used it for years now(dyed it purple in later years), and I've yet to hear somebody complain about it in one of them.
 
Well, I finally got the stack out today. I know I am slow so bear with me
20170419152237-X3.jpg


It looks like it was at least 1/2 clogged. Tomorrow I will be working on replacing the water pump and getting ready to reassemble after cleaning the cores on all three heat exchangers.
 
The pic doesn't show how much the radiator is clogged. When I shine the flashlight and look a lot more is clogged.

Tanner, I know you carry some pretty big loads. I don't remember you having cooling problems???
 
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