• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Radiator Drain on '99 GMC C3500 6.5l

Bernie

Bernie

Amateur Radio Operator - KJ4VOV
Messages
303
Reaction score
12
Location
Fredericksburg, VA
Okay, so it's time to flush the cooling system and refill. Except for one thing... how the heck does that radiator drain plug come out?

This is the type I have on the radiator and, as far as I can see, it's not removable. Or if it is then it needs a special tool. I've never seen one like it before.

plug.jpg

I'm hoping like hell I don't need to pull a hose to drain this truck. Those hoses and clamps are a PITA to get to...
 
Yeah, but how are you turning it? The way it's designed it's like an anti-tamper screw, only goes in and you can't back it out because the "ramps" on it cam the tool back out.
 
No joy... I've been at this since about 1 o'clock and I still can't get that damn plug out. To start with, could GM have put it in a more inaccessible position? You can't reach it (or even see it) from below or from the wheel well, and trying to get at it from the top means trying to hold the two power steering hoses and a battery cable out of the way, with a flashlight in your teeth, and using only one hand because there's no room for two in there. All I've managed to do so far is chew it up pretty good with pliers (I'll probably have to replace it if/when I ever get it out) and I think I might have cracked the radiator. Not really sure, and I'm not seeing anything leaking (besides the lines going to the oil cooler which I just discovered are leaking pretty badly) but there was a pretty ominous "CRACK!" earlier when I was trying to twist it...

I really wish there were a local shop I could take it to and have it done, but almost all the ones I've contacted have refused to touch it because they don't work on diesels, and the three that would do it all want to use regular green coolant (which is not rated for diesel use) or Dex-Cool (which is also not diesel rated, no matter what GM claims) instead of the proper diesel rated extended life CAT certified coolant I already have.
 
That one looks alittle different than what Im used to. Normally can be set in drain mode just with thumb and finger. The plug does not come out all the way, it just sorta slides back getting the oring to unseat.
 
Mine looks like that but the head is shaped like a wing nut so you can grab onto it with your fingers or gingerly with pliers.
 
I only change coolant when i loose it cause of a leak somewere that need fixing ie: head gasket or waterpump etc.
Too big a PITA to try to drain coolant on these trucks,one usually ends up busting something.
AFAIAC Green coolant is OK for diesels,..i don't use nothing else.
 
Some folks have good luck with it, but I'm one of those guys who doesn't like to do chores any more often than he needs to. The stuff I'm putting in is supposed to be good for 600k.

Oh, and just because it's one of those days... I had to take my truck on a fast trip to the store, about a mile from the house. Got there and noticed a line of oil behind me, leading all the way out of the lot. Crap.

Got it home again, but the oil pressure bottomed out as I hit the driveway. No knocking, so I'm keeping my fingers crossed. Too dark and too much oil under there to see what happened but I'm betting one of the cooler hoses let go.
 
Bernie said:
Some folks have good luck with it, but I'm one of those guys who doesn't like to do chores any more often than he needs to. The stuff I'm putting in is supposed to be good for 600k.

Oh, and just because it's one of those days... I had to take my truck on a fast trip to the store, about a mile from the house. Got there and noticed a line of oil behind me, leading all the way out of the lot. Crap.

Got it home again, but the oil pressure bottomed out as I hit the driveway. No knocking, so I'm keeping my fingers crossed. Too dark and too much oil under there to see what happened but I'm betting one of the cooler hoses let go.
Click to expand...

That alone should have been cause for dumping in some oil, even if it involved walking to get some. I too hope your engine is fine, but the ignoring the issue may have proved to be a even bigger problem.

keep us posted on the results, hopefully its ok.
 
GM Guy said:
That alone should have been cause for dumping in some oil, even if it involved walking to get some. I too hope your engine is fine, but the ignoring the issue may have proved to be a even bigger problem.

keep us posted on the results, hopefully its ok.
Click to expand...

I did top it off before going home. I always carry a gallon of Rotella on the truck for just such occasions.

The cause turned out to be twofold: a front main bearing seal that suddenly decided to sling oil for no particular reason (seal looked absolutely perfect once we got it off -and the shaft of the balancer was glass smooth) and a clip holding in one of the oil cooler lines had partially broken, allowing the line to move around in the socket and leak. It must have been doing it for some time though, as it actually wore a groove in the ball on the line. Oddly, this seems to have been worked on before as the line had a tag on it with a 2001 date on it and it's a 1999 truck. Replaced both sockets, the seal and the oil line for a total of about $240 in parts and the same in labor at a friends shop. The parts were the killer because we had to get then from the dealer. No one else had them in stock and we couldn't tie up his lift while waiting for parts to come in.
 
You must log in or register to reply here.
Back
Top