freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Chuck78 · 05-22-2009, 07:01 PM

So while examining my clutch line/hose attachment with a mirror behind the engine on top of the bell, I discovered where a tiny antifreeze leak was coming from! My freeze plug on the rear of my driver's cylinder head has a hard scale built up on it and has corroded to the point where I have a real small leak. I tried to scrape the "gunk" off it it and realized that it was hard, crusty scale from corrosion.

I have 4-1/2" at most between the back of this head and the firewall. I'm lucky it wasn't hte pass. side, as it sits way closer to the firewall.

I'm looking for opinions on how hard this thing is going to be to remove. I've only removed freeze plugs from one bare block that was pulled, not sure how this will go with trying to do without pulling the head. Any ideas guys?

I was thinking right angle attachment on dremel, and try to drill a hole in it and pop it out. Not sure how well I could get a hammer and punch/chisel in there. It'd be a real short chisel or punch, and at an angle, if I were to try it.
I was planning to do my power brake upgrade and new separate clutch master on Monday, but that's just gonna get in the way of doing this freeze plug if I put all that stuff on the firewall.

Let me know what you guys think, as far as degree of difficulty and other ideas. I don't want to pull the head if this thing might be do-able other ways. Thanks!

Chuck78 · 05-22-2009, 07:03 PM

I got a screw in rubber compression type of plug in case the block was corroded or pitted, but I'll probably try to hammer in a brass plug if I can. What do you guys think of the durability of the rubber compression type???

Thanks

**Corts60** · 05-22-2009, 09:54 PM

The rubber one obviously won't last as long as a brass plug, but if that is easier to get in, I would go that route.

I also agree about the dremel idea. Might work out the best for you.

Chuck78 · 05-23-2009, 08:10 AM

My buddy said "there's always the hillbilly method, just JB Weld it!" I think I'd rather fix it right the first time, but once I start, there's no going back.

I just have no idea the degree of difficulty that I'll have trying to get back in there with so little room to work and prying/chiseling out the old one.

If the block is pitted out, I suppose I could just jack it up from the rear to make sure no freeze drains out, and clean it out real well, blow it out, and throw in some JB Weld and let it dry and sand it out, and then install a new brass freeze plug.

Is there any type of sealant that I should use when hammering a brass plug into the block or head? I was told that they just get hammered in dry.

Again, any estimation on how hard this will be to get out with only 4-1/2" to the firewall would be greatly appreciated. Stinks cus I wanted to do the power brake booster/dual master/separate clutch master upgrade Monday, but if I do that first, it will just make the freeze plug harder to get to.

BigSix · 05-14-2014, 02:26 PM

Bringing back a post from a million years ago:

I have a big leak from the back of the block too...up high and drivers side...any chance it can be fixed without pulling heads?

05-22-2009, 07:01 PM	#1
Chuck78 Registered User Join Date: Apr 2005 Location: Columbus, OH Posts: 197	freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 So while examining my clutch line/hose attachment with a mirror behind the engine on top of the bell, I discovered where a tiny antifreeze leak was coming from! My freeze plug on the rear of my driver's cylinder head has a hard scale built up on it and has corroded to the point where I have a real small leak. I tried to scrape the "gunk" off it it and realized that it was hard, crusty scale from corrosion. I have 4-1/2" at most between the back of this head and the firewall. I'm lucky it wasn't hte pass. side, as it sits way closer to the firewall. I'm looking for opinions on how hard this thing is going to be to remove. I've only removed freeze plugs from one bare block that was pulled, not sure how this will go with trying to do without pulling the head. Any ideas guys? I was thinking right angle attachment on dremel, and try to drill a hole in it and pop it out. Not sure how well I could get a hammer and punch/chisel in there. It'd be a real short chisel or punch, and at an angle, if I were to try it. I was planning to do my power brake upgrade and new separate clutch master on Monday, but that's just gonna get in the way of doing this freeze plug if I put all that stuff on the firewall. Let me know what you guys think, as far as degree of difficulty and other ideas. I don't want to pull the head if this thing might be do-able other ways. Thanks! __________________ Chuck in Ohio 1962 GMC 1000 Panel Truck - 305D/Saginaw 4sp soon: 351C V6 + AX15 5sp OD trans, & 75-87/91 disc brake front end* 1988 Suzuki Samurai 4x4 project, VW 1.9L mTDI, Toyota R151F transmission & Toyota full floater axles, LWB body tub stretch project* *Many 1977-1979 Suzuki GS motorcycles, Kawasaki KDX220R, '77 Suzuki PE250, etc

05-22-2009, 07:03 PM	#2
Chuck78 Registered User Join Date: Apr 2005 Location: Columbus, OH Posts: 197	Re: freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 I got a screw in rubber compression type of plug in case the block was corroded or pitted, but I'll probably try to hammer in a brass plug if I can. What do you guys think of the durability of the rubber compression type??? Thanks __________________ Chuck in Ohio 1962 GMC 1000 Panel Truck - 305D/Saginaw 4sp soon: 351C V6 + AX15 5sp OD trans, & 75-87/91 disc brake front end* 1988 Suzuki Samurai 4x4 project, VW 1.9L mTDI, Toyota R151F transmission & Toyota full floater axles, LWB body tub stretch project* *Many 1977-1979 Suzuki GS motorcycles, Kawasaki KDX220R, '77 Suzuki PE250, etc

05-22-2009, 09:54 PM	#3
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 The rubber one obviously won't last as long as a brass plug, but if that is easier to get in, I would go that route. I also agree about the dremel idea. Might work out the best for you. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

05-23-2009, 08:10 AM	#4
Chuck78 Registered User Join Date: Apr 2005 Location: Columbus, OH Posts: 197	Re: freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 My buddy said "there's always the hillbilly method, just JB Weld it!" I think I'd rather fix it right the first time, but once I start, there's no going back. I just have no idea the degree of difficulty that I'll have trying to get back in there with so little room to work and prying/chiseling out the old one. If the block is pitted out, I suppose I could just jack it up from the rear to make sure no freeze drains out, and clean it out real well, blow it out, and throw in some JB Weld and let it dry and sand it out, and then install a new brass freeze plug. Is there any type of sealant that I should use when hammering a brass plug into the block or head? I was told that they just get hammered in dry. Again, any estimation on how hard this will be to get out with only 4-1/2" to the firewall would be greatly appreciated. Stinks cus I wanted to do the power brake booster/dual master/separate clutch master upgrade Monday, but if I do that first, it will just make the freeze plug harder to get to. __________________ Chuck in Ohio 1962 GMC 1000 Panel Truck - 305D/Saginaw 4sp soon: 351C V6 + AX15 5sp OD trans, & 75-87/91 disc brake front end* 1988 Suzuki Samurai 4x4 project, VW 1.9L mTDI, Toyota R151F transmission & Toyota full floater axles, LWB body tub stretch project* *Many 1977-1979 Suzuki GS motorcycles, Kawasaki KDX220R, '77 Suzuki PE250, etc

05-14-2014, 02:26 PM	#5
BigSix Registered User Join Date: Mar 2014 Location: MD/VA/PA Or Inbetween Posts: 413	Re: freeze plug replacement difficulty? rear of driver's cyl. head GMC 305 V6 Bringing back a post from a million years ago: I have a big leak from the back of the block too...up high and drivers side...any chance it can be fixed without pulling heads?

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