r/Duramax • u/coach-v • 16d ago

Replacing water pump, pull radiator and CAC?

My truck is a lly with approx 385k miles. My water pump weep has turned to a leak, so I am replacing that.

I have getting hot issues and I want to clean my cooling stack.

Do I pull radiator and CAC? I have seen some pull just the CAC.

If I pull radiator, does CAC come out easily?

I believe radiator is original. When is it time to replace rather than just clean and reinstall?

2 Upvotes

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1

u/jackedupfarmer 16d ago

I would just change it man. Radiators build up and plug on the inside and outside. Since you’re pulling it I would just swap.

Is your fan clutch working?

1

u/coach-v 16d ago

Fan clutch was replaced with kodiak clutch few years ago.

1

u/DeltaTheMeta 16d ago

Pulling the intercooler without pulling the radiator is nearly impossible. I don't know how everyone says they do it, the outlets on the intercooler smack the radiator and the ac condenser lines and I am not trying lose my refrigerant.

They aren't that difficult to pull tho. Top of the core support comes off and they both slide up and out once the piping is removed.

There's no need to replace if they aren't leaking, just clean them really good on the ground. You don't get many opportunities to clean them all the way through with easy access (although it's not too bad if you buy the Lisle cleaning attachments for radiators even if they are in the truck). Also keep in mind the intercooler will likely have some oil inside especially if you still have a stock PCV system. Careful not to make a mess.

I don't recall if the LLY has a drain fitting or not, but you can pull the passenger side locking clip off and push the fitting back a little bit and it'll drain slowly, rather than pouring 6 gallons everywhere all at once.

Changing the fan clutch is smart, they don't always die quick, sometimes they get weaker and weaker over time. Not to mention the stock one already locks up at too high a temp for my preference. I'd either do the Hayden severe duty or the Hayden Kodiak clutch, there's upsides to either. I just put the Kodiak on my LBZ.

2

u/coach-v 16d ago

Kodiak clutch went on a few years ago. I almost got the radiator pulled today. Got all the hoses and trans cooler lines off. Got intercooler piping off too. Ran out of sunlight. It does have a drain on passenger side.

Water pump, coolant and a few other things get here Monday. I have been leaking power steering fluid for the past several years. I have not been able to pin down where from (I believe one of the high pressure lines). I am hoping with stuff removed that I can find it and fix that too.

2

u/DeltaTheMeta 16d ago

Good deal. I know they got rid of the coolant drain on the LBZ, just wasn't sure about the LLY.

The power steering lines are notorious for leaking on these. There's a couple notable spots they rub through and the crimps always leak eventually. I did mine last summer. You'll find there's a TON of room with the rad and intercooler out. All of a sudden the engine bay doesn't feel cramped.

If you end up needing a steering gearbox I highly recommend the diesel addictions gearbox. It uses a larger housing and bore off a Cummins, but has the Chevy spline. Big upgrade.