About 3 weeks ago I changed my 2 year old anti freez in the ZZ 502 which is in my 65 Corvette. I always use the Green Prestone stuff. I ran the motor up and filled the rad to the top. Warmed her up and took her for a cruz. Checked her out and no leakes anywhere.

After I came back and shut her down ...I waited for the motor to do it's normal thing which is to "Puke " out what she don't need. After a few min's she puked about a pt or so and leveled off about 1'' below the rad cap.

All was fine. The Corvette is store outside in a "Cover It" tent inside a "Car Capsaul" wher the air is changed 4 times every hour. Today I took he out for a spin as the temp droped to about 45*. It's been cold up here in the South Jersey area.

After coming back I noticed a drip from under ther vette. I jacked her up and saw the head gasket is wet in one place and dips about once every 10 seconds. After a while it stopped when the pressure and temp dropped off.

Either I need to check my Headbolt torque ..or repace the gasket. Tried to find the Head Bolt torque Pattern on the web but no luck. Anyone have a copy of that. The ZZ 502 uses Aluminum Oval Port Heads on the Gen V BB .

Why would that sucker start leaking....after 2 years?? I kmow it's because I chnged the Antifreez..

Any help would be appreciated. Thanks in Advance.

The Knowledge Base on this site has the info,
http://www.hotrodders.com/kb/chevrolet-engine-tech

If it's leaking it was not sealed correctly to began with, I use Permatex #2 with very good retaining of the seal.
Check all the hose's before pulling off the heads, maybe a pressure test on the coolant system.

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Thanks Bad 80,
I must have missed that. I did check the Knowledge Base before I posted.
This is a GMPP ZZ502 Deluxe factory assembled Crate motor. I don't want to have to pull the head,. I'll have to if the Head bolts are at the Torque spec.

Nothing in there on a GMZZ502. All references are made to a 502 with smaller valves and and rectanular ports. My motor has oval ports. Guess I'll have to contact GM

It can be 1 or 2 bolts leaking from the threads, the heads do not have to be pulled to fix it, you will have to drain the block and pull the bolt/studs out one at a time and use the Permatex#2 for good sealing & re-torque.
Pull the valve coverts to check if their leaking inside also. LOL

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Yeah.. plan on pulling the covers and peeking inside. Also checked the oil...looks good.

I had a simular problem on my early 86 Vette with FI and an Aluminum intake on an Iron head. Had to pull a few intake bolts as the green goo was weeping up the bolt threads and making a nice swiming pool for the bugs in the intake runner valley.

Still need the tightening Pattern.....Rats!!!

here is the info,
http://www.edelbrock.com/automotive...l/7000/7760.pdf

http://www.autozone.com/az/cds/en_u...ges.htm#hd1-1-1

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Thanks George...You Da Man.....!!!

I know Edelbrock makes the heads and intake for GM on the 502. I have the torque specs and amount of tightening passes in my manual. The Torque spec on Edelbrock site are different.

The Factory manual I have says Long Bolts Final Pass 75 lbs....Short Bolts..65 lbs final Pass. But the main thing is I have the Pattern Now. Thanks Again for taking the time to search for me.

Also I sent you an email to the address you sent me in the PM.
Thanks Again. Mark

From the manual Torque in step's,
Step
1 40#
2 60#
3 80#
Note:
ON BIG blocks with aluminum heads, tighten the short bolts to 65# and the long to 75#

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Luv the smell of NITRO in the morning.

Here is a scan from my manual.

Attached Thumbnails

 

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Yep you got it.....


From the 502/502 Manual....

Long Bolts First Pass 25 lbs
" Second Pass 50 lbs
" Final Pass 75 lbs

Short Bolts First Pass 20 lbs
" Second Pass 40 lbs
" Final Pass 65 lbs



"