Radiator draincock?

JayArr

Original poster
Member
Sep 24, 2018
504
Mission BC Canada
Hey all.

So I get this brand new GM radiator and I notice the plastic has been molded for a draincock. It looks like it just wasn't drilled out and the valve installed.

I've been told that GM never put them in this vehicle but maybe the engineer that specified these holes in the mold was also in charge of a radiator in another model that actually got the valve.

Take a look at the pictures and if they look familiar please post up what vehicle you've seen them on. It would be great if we could order the GM drain cock from a different vehicle line, drill out the hole and retrofit our rads so they drain easily.
 

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Reprise

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Jul 22, 2015
2,724
My 2003 Sierra (6.0L; larger 34" rad) has one on the bottom LH (driver) side.

As I'm sure you know, GM built half of their empire on using common parts across lines, so it wouldn't surprise me at all to find out there was a common mold used on the radiator.

Supposedly, GM dropped the petcocks in '03, but I have one (would've been good to know before I took off the lower hose!) There's even a provision for a little hose that attaches to the petcock, and it tucks away when not needed. Mine didn't have the hose; that was gone before I got it. But I do have the petcock in my full-size PU. Not sure if I have a pre-'03 radiator; it would be impossible for me to tell. From what I can tell, the associated parts (cooler lines, A/C condenser, trans cooler) are original to the truck. But that's a guess, too, obviously.

My '03 Envoy (5.3L) has no petcock at all. AFAIK, even the very first '02s never had one.
 
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gmcman

Member
Dec 12, 2011
4,656
My 02 had a petcock, and I believe is a 5/02 prod date. Had an Explorer take the nose off about 6 years ago and was replaced with a radiator W/O the petcock.

Baffles me why not providing a petcock was even debated.
 
Last edited:

Matt

Member
Dec 2, 2011
4,019
My 06/02 doesn't have one.
 
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Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
My 02 had one. All others after that didn't get one. Most aftermarket rads come with them. Add it to the list of things that were deleted to save a few pennies:
- radiator drain petcock
- engine low oil level sensor
- rear diff drain plug
- plastic radiator cover

Although not really deleted, things that they did which we can only think it was to save a buck or two:
- fake oil pressure gauge
- cheap radiator that was overcompensated with a mechanical big ass fan (other trucks eventually went to efans)
- weak 8" diff on I6 SWB trucks
- smaller front brake rotors on I6 SWB trucks
- hood prop rods! (even though the 9-7x has a gas cylinder)
 

Stugar

Member
Apr 17, 2019
48
Michigan
Don't forget the oil change access hatch that got value engineered out some time between 04 and 07. Honestly with the position of the filter on the 4.2L I honestly don't care, that filter sucks to get to through the old hatch.
 

gmcman

Member
Dec 12, 2011
4,656
that filter sucks to get to through the old hatch.

Yeah, I tried that about once...lol. Since then I remove three of the four 13MM bolts holding the splash guard, then loosen the LR bolt allowing it to swing out of the way. To keep the mess to a minimum, loosening the filter a few turns allowing the oil filter housing to drain for a couple min helps.

Some cars I use a funnel with a clear tube attached to catch the filter, letting the oil to drain into the catch pan. More tricky with the 4.2L.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
Off topic, but I cut a short piece of gutter (18"- 24" ?) one end in the drain pan the other up past the filter. Works with or without the hatch.
 
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