Coolant flush on the LMM
- Thread starter Dean E
- Start date
I was able to take to a GM parts guy. It appears that the only sell the fitting as a unit. What he gave me was 15797464. Looks like NAPA has a equivalent available for much cheaper. I would really just like to do the o ring but looks like that is not going to happen. Dean
It is surprising how much stuff can make its way through the other devices and end up on the radiator. I think you will be happy with the work that you have done.
I thought about that and would not have problems if the o ring was in a compression type of application. Being a slip fitting and the fact that the old seals are deformed from age I thought this would be the safer route. I hate to have to go back and redo things because something started leaking. Dean
Don’t remember what kit I have but one of my oring kits had the right side o-ring to put in it. 50k miles and no issues.
I’d rather change the whole unit like you did though. I wouldn’t do what I did again
I’d rather change the whole unit like you did though. I wouldn’t do what I did again
I was able to reach out to a dealership parts guy that was super helpful. He is the one that told me that this was sold as a fitting. He also had references to NAPA parts that showed two different units. a NOE 7305635 and a NHD 73051091 with both referencing the GM number 15797464. When I talked to NAPA in town they stated that one was a Original Equipment number and the other was a Heavy Duty number. Not sure what a HD unit would give you other than just costing more. That standard unit lists for $23 while the HD goes for $58 each. I got a couple of the $23 units coming. Should have them by Tuesday and be able to put everything back together next weekend. In the mean time I will be changing the thermostats. I doubt there is any issues with the ones I changed 3 years ago but the ones I have now are genuine GM units and with everything removed and the coolant drained it is kinda of a no brainer to change them out. I'm also making an air nozzle so I can blow out the backside of the heat exchanger. There is a little trash on the front of it but nothing like what I had on the radiator. Looking forward to getting it all back together and having my truck back. Dean
I have been aviation maintenance my whole life (36 years and counting), done engine rebuilds on cars and motorcycles. Not afraid to tackle most things as long as you don't need a bunch of specialized tools to do it. I'll never say that I have seen it all and know it all, I learn something new about everyday. Today was no exception! I never would have thought that much garbage could have made it to the radiator considering that you have the heat exchanger and AC condenser in front of it. Lesson learned! Dean
The heat exchanger is not as bad but it is still dirty. I can only hit the upper portion with my air nozzle and hose with the fan and lower shroud in place so I fabricated extension with a #4 aluminum line and a 90 degree end so I can clean the lower portion with some back flow.
Here is a snapshot I got from the GM parts guy I talked to on Saturday. He showed the NAPA parts listing equivalent. As you can see there are two different numbers for NAPA that reference the same GM number for the couplings for the radiator that go to the tranny cooler.
I ordered the OEM unit (standard duty). Not sure what the difference is between two but they both reference the same GM number. The standard one matches the ones I took out of the radiator perfectly. Maybe the HD unit has a longer warranty, but the price was about double to the HD ones. One thing I found on the web today is to ONLY take out one fitting at a time. If you take out both the cooler unit can drop into the plastic case and you can spend hours trying to get it to line up to get the fittings started correctly in the threads of the cooler. Don't know how true this is but I was not going to chance it. All ready to drop the radiator back in the truck now.
Interesting enough I did find out with a magnet that the original GM units are aluminum and the NAPA ones I got are steel. Dean
I ordered the OEM unit (standard duty). Not sure what the difference is between two but they both reference the same GM number. The standard one matches the ones I took out of the radiator perfectly. Maybe the HD unit has a longer warranty, but the price was about double to the HD ones. One thing I found on the web today is to ONLY take out one fitting at a time. If you take out both the cooler unit can drop into the plastic case and you can spend hours trying to get it to line up to get the fittings started correctly in the threads of the cooler. Don't know how true this is but I was not going to chance it. All ready to drop the radiator back in the truck now.
Interesting enough I did find out with a magnet that the original GM units are aluminum and the NAPA ones I got are steel. Dean
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Yes, having the cooler fall down into the bottom of the radiator is very real. But it will likely be stuck to the tank and stay in place. But worth doing one at a time and not risking it
Are they plain steel or stainless? I don't think I'd worry either way as there are both steel and aluminum in the coolant system. So unlikely to corrode or cause issues
I would say anodized steel. I agree, I'm not worried about corrosion. BTW what NAPA charged me for the fittings was the much closer to the cost price not the list. For that money it's very cheap insurance. I should be able to put everything back together this weekend. Thanks for all the help! Dean
Well I got the couplings installed for the tranny cooler and put everything back together. Started the engine and let it run for a while getting up to temp. Everything looks good so far. Went ahead and did a bunch of routine maintenance since everything was opened up. Oil change, lub and tire rotation. Here I got a bit of a surprise! Took off the rear wheel to move it up front and found this. WOW. did not notice and vibrations out back and not sure it has been this way but I'm glad I found it now. I think this is the tire that I took a nail in about a year and a half coming back from fishing in MN. Seemed like a good plug, no further leaks but not sure when it start to come apart. I have been a fan of the Falken Wildpeaks, good tread life and don't howl going down the road. Remaining tires have about half life left on them. Debating to change out two of them or just do all four with new TPMS sensors. Got an Autel programmer so sensors are about $120. The sensors I have in there right now are about 7 years old. Dean
Yeah, it is probably the way I will go. When it comes to my Duramax I usually do not take the cheapest way out. I have been in aircraft maintenance my whole life. Even though there is some good life on my other tires I will likely change out all 4 with new TPMS to make sure I wont have any issues going down the road. When I did my last tire change I had a shop in St Louis do a reconditioning on my 17 inch aluminum rims. They did a great job on my stock rims. My original rims had clip on weights on them. This works but usually damages the finish on the rims and allows corrosion to get under neigh the clear coat, which was the shape mine were in. This shop bakes the finish off then paints the recesses of the stock wheels. bead blasts them they then machine the finished aluminum areas of the rim and bake on a new clear coat. Makes the factory rims look like new! I just need to make sure the shop that does the work protects the finish and uses stick on weights on the inside of the rim to balance them. Not a job for a high school kid that does tire changes for a shop during the summers! Dean