Radiator Drain Question - ZR-1 Net Registry Forums

avijay · 12-05-2011

Getting ready to pull the plenum this weekend to get to my injectors and wanted to know what was the easiest way to drain enough coolant needed to start the project? Do I have to get under the car to do this or is there an easier way to access a drain port from above and move forward? Thx!!!!!

tomtom72 · 12-05-2011

the rad petcock can be reached from on top. Right side of car down by the short hose that goes to the T-stat housing. Just under or right near the hose, but a bit lower is the petcock.

If you are not pulling the injector housings draining the rad will be more than enough. If you are pulling the I/H's off then just be careful as the level will be right at the head-I/H matting surface. Have some rags handy.

Tom

Z51JEFF · 12-05-2011

Draining about a quart should be enough if the plenum is the only thing you re pulling off.At the front right wheel,wheel turned reach down between the wheel and wheel well and you should be able to reach inside a small 1/2 circle guard and reach the petcock.

avijay · 12-05-2011

Thanks for the info, I assume this is the draincock I'm looking to access?

Another question, hopefully not too stupid, but do I just simply unscrew (counter-clock) a little or all the way out, what's the proper operation to start the drainage and stop drainage after taking out about a quart or so? Thanks again.

sdycke · 12-05-2011

yes, counter clock wise. A couple of turns should start a flow. A pair of pliers my be necessary for extra GENTLE persuasion if the petcock hasnt been opened in many years. for a faster flow, just gently (by hand) pull the petcock out slightly after a few more turns (when further turning dosent increase the flow). close by hand. and push in first if you had pulled it out. it is always easier to deal with the consequences of too little force (a leak) than too much ( busted petcock, cracked tank). and if using pliers, its best from underneath. me thinks.

Paul Workman · 12-06-2011

Because the petcock tends to dribble, it can be messy, even with a catch pan under it - coolant tends to run along the frame rails, etc, across the front of the car. But! A handy shallow (approx 18x30x5") rectangular plastic storage tub (from WalMart) can be laid down with one end under the petcock, and the other end set so the tub is parallel to the radiator, under the frame. That way you'll catch it all, with no mess!

I have a 5 gallon plastic gas can, dedicated to storing and re-pouring coolant. It works out nice.

Now, all that said, once the plenum is off it is an ideal time to drill and tap and plug the TB coolant passages in the IHs. Unless you intend to do a lot of driving at -10F, you'll never need to heat the TB. Then, if ever you need to pull the plenum again (lots of stuff under there) you won't have to fuss with draining, or getting the air out of the system, again. Just a thought!

P.

ZR1Vette · 12-06-2011

What they said just showing it with a picture (thermostat housing is removed)

Here is the petcock (red arrow) with the thermostat housing installed (just for a point of reference) and the yellow arrow shows the plastic channel that runs under the radiator and this is where coolant will collect and run down across the rails etc. so you need to put a low collector pan under the petcock AND newspaper/rag under the radiator... as said before can get a bit messy.

tomtom72 · 12-06-2011

Jez Mike, I don't know between you and Ricky I should just let them come and take my car for neglect unbecoming a Z owner in good standing!

That is some kind of clean I can't describe! Kudos to ya!

Tom

avijay · 12-06-2011

Quote:

Originally Posted by ZR1Vette

What they said just showing it with a picture (thermostat housing is removed)

Here is the petcock (red arrow) with the thermostat housing installed (just for a point of reference) and the yellow arrow shows the plastic channel that runs under the radiator and this is where coolant will collect and run down across the rails etc. so you need to put a low collector pan under the petcock AND newspaper/rag under the radiator... as said before can get a bit messy.

Great pic, thx! It's pics like that, that make these jobs so much easier.

12-05-2011	#1
avijay Join Date: Nov 2011 Location: Glen Allen, VA Posts: 49	Radiator Drain Question Getting ready to pull the plenum this weekend to get to my injectors and wanted to know what was the easiest way to drain enough coolant needed to start the project? Do I have to get under the car to do this or is there an easier way to access a drain port from above and move forward? Thx!!!!! __________________ 1970 LT-1 - sold 1971 Vert - sold 1972 454 - sold 1996 Grand Sport - sold 1999 C5 - sold 1969 Mustang Mach1 - sold 1991 ZR-1 - sold 2008 Z06 - current

12-05-2011	#2
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Radiator Drain Question the rad petcock can be reached from on top. Right side of car down by the short hose that goes to the T-stat housing. Just under or right near the hose, but a bit lower is the petcock. If you are not pulling the injector housings draining the rad will be more than enough. If you are pulling the I/H's off then just be careful as the level will be right at the head-I/H matting surface. Have some rags handy. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

12-05-2011	#3
Z51JEFF Join Date: Dec 2007 Location: Fremont,Ca Posts: 3,085	Re: Radiator Drain Question Draining about a quart should be enough if the plenum is the only thing you re pulling off.At the front right wheel,wheel turned reach down between the wheel and wheel well and you should be able to reach inside a small 1/2 circle guard and reach the petcock.

12-05-2011	#4
avijay Join Date: Nov 2011 Location: Glen Allen, VA Posts: 49	Re: Radiator Drain Question Thanks for the info, I assume this is the draincock I'm looking to access? Another question, hopefully not too stupid, but do I just simply unscrew (counter-clock) a little or all the way out, what's the proper operation to start the drainage and stop drainage after taking out about a quart or so? Thanks again. __________________ 1970 LT-1 - sold 1971 Vert - sold 1972 454 - sold 1996 Grand Sport - sold 1999 C5 - sold 1969 Mustang Mach1 - sold 1991 ZR-1 - sold 2008 Z06 - current

12-05-2011	#5
sdycke Join Date: Jul 2011 Location: grosse isle, manitoba, canada Posts: 52	Re: Radiator Drain Question yes, counter clock wise. A couple of turns should start a flow. A pair of pliers my be necessary for extra GENTLE persuasion if the petcock hasnt been opened in many years. for a faster flow, just gently (by hand) pull the petcock out slightly after a few more turns (when further turning dosent increase the flow). close by hand. and push in first if you had pulled it out. it is always easier to deal with the consequences of too little force (a leak) than too much ( busted petcock, cracked tank). and if using pliers, its best from underneath. me thinks.

12-06-2011	#6
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: Radiator Drain Question Because the petcock tends to dribble, it can be messy, even with a catch pan under it - coolant tends to run along the frame rails, etc, across the front of the car. But! A handy shallow (approx 18x30x5") rectangular plastic storage tub (from WalMart) can be laid down with one end under the petcock, and the other end set so the tub is parallel to the radiator, under the frame. That way you'll catch it all, with no mess! I have a 5 gallon plastic gas can, dedicated to storing and re-pouring coolant. It works out nice. Now, all that said, once the plenum is off it is an ideal time to drill and tap and plug the TB coolant passages in the IHs. Unless you intend to do a lot of driving at -10F, you'll never need to heat the TB. Then, if ever you need to pull the plenum again (lots of stuff under there) you won't have to fuss with draining, or getting the air out of the system, again. Just a thought! P. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry Last edited by Paul Workman; 12-06-2011 at 06:35 AM.

12-06-2011	#7
ZR1Vette Join Date: Dec 2007 Location: Reston, Virginia Posts: 939	Re: Radiator Drain Question What they said just showing it with a picture (thermostat housing is removed) Here is the petcock (red arrow) with the thermostat housing installed (just for a point of reference) and the yellow arrow shows the plastic channel that runs under the radiator and this is where coolant will collect and run down across the rails etc. so you need to put a low collector pan under the petcock AND newspaper/rag under the radiator... as said before can get a bit messy. __________________ Michael :cheers: [I][SIZE="2"]1990 RED on RED #566[/SIZE][/I] [I][SIZE="2"]WAZOO MEMBER[/I][/SIZE] Last edited by ZR1Vette; 12-06-2011 at 09:07 AM.

12-06-2011	#8
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: Radiator Drain Question Jez Mike, I don't know between you and Ricky I should just let them come and take my car for neglect unbecoming a Z owner in good standing! That is some kind of clean I can't describe! Kudos to ya! Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member