# Small oil leak turns into big project.



## skurfan (Sep 19, 2012)

Well, my '67 GTO was leaking a bit of oil onto the garage floor. I decided to try and find the source and decided it was the rear main seal. Pulled the motor and decided to clean up and paint the engine bay and motor also. This car sat idle for 35+ years in a guy's garage after a rebuild before I wrestled it away from him last year. Exposed the crank and found the culprit. There was some corrosion on the crank where the rear seal meets it. Thus...the crank came out and off to the machine shop. I guess they felt sorry for me because they polished that off for free. Good news is, the bearings still look new and so does the rest of the motor. Going to start putting it all back together tomorrow. That small amount of oil doesn't seem like such a big problem looking back on it now....but at least it will be right. Lesson learned. First question when looking at a classic will always be....how long has this car sat idle?


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## Instg8ter (Sep 28, 2010)

Pontiac rear main seals require VooDoo sacrifices to the car gods to be leak free, no matter how long they sit. And yes as annoying as kicking a pan under the car is they are almost impossible to do without pulling the motor. Mine went nearly 2 years and a few thousand miles on the build with the viton seal before it started to drip a little. They also have graphite seals now, but it seams the best were the original asbestos ropes.


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## chuckha62 (Apr 5, 2010)

Did you pull the pistons all the way out, or just push them to the top of the bores? If you pulled them out, then new rings and a hone job may be in order.


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## geeteeohguy (Feb 2, 2008)

I think (and hope) he just pulled the crank. Skurfan, I did the same thing on my '67 back in '11. And one thing lead to another. Mine was ok because the car has never sat inactive, so no corrosion. Just a cat turd for a rear main seal. Ended up taking the opportunity to: install new freeze plugs, R&R water pump and timing cover, coat timing cover and spacer plates with glyptal, set plate clearances, paint engine, detail engine bay, steam clean underside of car, overhaul tired transmission, install new steel trans lines, rebuild carburetor, tune up engine, install new steering gearbox, overhaul power steering pump, etc. The engine was out for a couple of weeks, but now I have a leak free car that runs perfectly. To be able to drive it 130 miles at speed to visit friends and park it in the driveway for hours and not leave a drop of _anything_ is a true bagging right with a 47 year old Pontiac. Well worth the effort. A lot of 'idle' cars will loose all the oil film off of a crankshaft, and when the vehicle is cranked years later, the crank will grab onto the seal and pull it apart. Not uncommon. Also, corrosion behind the aluminum timing cover is not uncommon. That's why I coat 'em with glyptal.


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## skurfan (Sep 19, 2012)

I have pulled the timing cover and water pump. Crank bearings are like new. I have not pulled the pistons and believe them to be excellent. Detailed the engine bay, painted the engine and new seals. I will hope for the best. Geeteeoguy, I have done pretty much everything you mentioned over the past nine months. Next will be prepping for paint over the next few months.


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