Best Method for Coolant Flush/Fill ?

[TIM Z]

Having only Done coolant changes/flushes on gassers,

Im wandering whats the best way or whatever way you guys do this on the Dmax.

Going to flush out the pink and put some green and distilled water in.

Thanks in advance

 

[lotsofmiles]

seems like i couldnt find a whole lot out about this topic.

I gave up and took it in.

 

[bullfrogjohnson]

I just drained the whole system then kept refilling water. Then I would let the engine run till the thermostat opened up and then drained with water until everything was clean. Then refilled the whole system with distilled water and green coolant. Take about and hour to do it right.

 

[jmoore]

Check with your local shop and see if they offer BG products they have a coolant flush mechine that hooks in to the upper rad. hose and replaces all of the coolant in the system.:happy2:

 

[Killerbee]

When cold, yank the lower rad hose. That drains 85%.

Reattach the hose, and fill the degas, start the truck and keep filling to the top.

Stop the truck before it gets hot and pull the lower rad hose again, that is 98%.

 

[MACKIN]

The best way is the right way. Avoid HOT temp readings

IF your going to use distilled water have plenty on hand and use for flushing. I also did it with the truck at normal operating temperature.


Shouldn't have to tell you but with the truck not running of course and be cautious as the fluid will be warm and splash around a bit. Do your part and be environmentally friendly. Remove the radiator cap before shut down.



Get a empty 5 gallon bucket and locate the petcock in the radiator open and drain in the empty bucket . Once it's done draining refill with distilled water and restart the vehicle. Not necessary to put the radiator cap back in place. Allow the fluid to circulate top off as necessary.

Repeat the drain process and refill until you see clear fluid coming out of the petcock.

With having the coolant capacity at hand ,I don't recall and I'm to lazy to look it up,drain off half of the capacity approx and refill with your choice of antifreeze.

Allow the fluid to circulate and top off as necessary. Leaving the radiator cap off raise the RPM's allowing it to burp off any air pockets. Test antifreeze for proper temperature protection.

It's simple but messy and takes about an hour. This is the procedure I did.

 

[TIM Z]

Thanks guys for the info, really appreciate it.

Yeah, im enviromentally friendly you could say, i use my sons old Kiddie pool to drain the old coolant into, then use my little sump pump to put it into 5 gal drywall buckets to take to my friends at the dealer for disposal, i dont want to polute my own water!


I wasnt sure if our radiators had a drain cock.

Glad to see im not the only one running green.

 

[hondarider552]

Tim, the lbz's dont have a drain on the passenger side like the lb7's do.

 

[the4wheeler]

Tim, the lbz's dont have a drain on the passenger side like the lb7's do.

X2
it was very irritating to find out there was no petcock on my LBZ radiator.
Whiskey. Tango. Foxtrot. GM!

 

[TIM Z]

Tim, the lbz's dont have a drain on the passenger side like the lb7's do.

This is one reason i asked, cuz i couldnt find one!

 

[hondarider552]

:rofl:
Think with your dipstick jimmy!

 

[MACKIN]

Tim, the lbz's dont have a drain on the passenger side like the lb7's do.

Well aint that dumb.............



Is there a block drain or what is the procedure in the GM service manual for draining the coolant system? It can't be pulling the lower radiator hose.

 

[TIM Z]

Good question cuz pulling the lower hose is my only option right now.

 

[JoshH]

Well aint that dumb.............



Is there a block drain or what is the procedure in the GM service manual for draining the coolant system? It can't be pulling the lower radiator hose.

Actually it could be, cause that's it! At least it's a "quick connect" fitting. No hose clamp or anything...

 

[TIM Z]

I hate those damn quick clamps on the Rad hoses. Got my share of pinched fingers from those sonsobitches.

 

[Killerbee]

The lower hose is extremely simple, and faster to drain, about 10 seconds. Use channel locks.

A petcock takes 10 minutes.

You can do a coolant flush in 15 minutes, if you don't complicate it.

If a high mileage vehicle with poor maintenance, consider running a light degreaser till a bit warm, not hot. Then drain 3-4 times, on the last drain use bottled, distilled or RO water.

No oil based coolants. Ethylene Glycol, Di-ethylene Glycol, or Propylene Glycol (Evans)...each 96%...pH buffers and anti-corrosion, and anti-cavitation additives, 4%.

 

[lotsofmiles]

Did you end up doing yours Tim?

I'm getting close to another change and am trying to decide if I want to do it or take it in. I think they charged me about $100 last time

 

[Jared Duramax]

would it be faster to pull the thermostats, then drain and fill the radiator and run the truck for a few min then drain it all back out?

 

[mead]

On the lmm there is no petcock there is however a block drain on the drivers side. It will drain the entire system without taking off the cap on the overflow. This was the process described in the factory manual.

The way I performed the service was to crawl under the truck with a flashlight, a rack of metric sockets, 3/8 impact with a medium extension and a kiddie pool.

I cannot recommend this method for the faint of heart.

You will be covered in hot coolant but by the time you get out of the shower the truck will be drained and you can crawl back under and put the plug back in.

I used some Teflon tape on mine, I think or at least I thought about it. Anyway I put 2 gal of Dex and about 2 or so of distilled in the overflow tank and started it topped it off etc. Drove to Texas

for what its worth I changed at 35000 ish and I used Dex cool because I had some I am not in love with the stuff and will change to a good diesel specific coolant next time but I always change about 30,000 to 35,000 miles.

jim

 

[JD4440]

It almost looks as if you could use a long extension and get it from a safe distance (out of the shower). Looks to be maybe a 15mm ?