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Siezed oil drain plug


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I still have nightmares about the time I tried to over-tighten the oil drain plug when my dad was showing me how to do it on my first car. Apparently, the previous owner of my 73 did not have a similar experience.

The bolt is cranked on pretty good. I think the car has sat for a few years too. So, it may be rusted a bit too. I have never had this happen on any car that I have owned (for an oil plug!). So, it is somewhat new territory.

Does anyone have any advice how to loosen the plug? I bought a replacement plug, (naively) planning to replace a slightly rusty plug. So, I don't care how it gets off, as long as it gets off.

I didn't try a cheater bar yet. So, that's still an option.

Should I just go ahead and replace the whole oil pan and be done with it? I really hate torquing on bolts when I am under the car. So, I am not against this.

I thought about applying some heat with a torch. But, I changed the fuel filter earlier and I didn't want so set the thing on fire.


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I'd try some PB Blaster or Kroil penetrating oil and let it sit for a while before trying the breaker bar. I'd hate to try removing the oil pan while it's still full of oil. If you end up having to go that route I've seen a pump system that let's get get the oil out through the dipstick hole.

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Yes - Kroil penetrating oil - Aero-Kroil in the spray can - would be the best. The problem is you have to order it on-line, then wait three of four days to get it.

In my opinion - everyone that is working on 30+ year old cars - should order a couple cans of <a href=http://www.kanolabs.com/ TARGET=NEW> Aero-Kroil</a> before starting to work on the car. -yes, it is that good-. Use often, it saves a huge amount of time, that would otherwise be spent on drilling and taping broken bolts/striped nuts etc.

PB-Blaster can be purchased at just about any auto parts store... It's a stop gap measure while waiting on the Kroil to arrive.


Put the longest box end wrench you have on the oil drain nut - hold the wrench firmly in place and hit the other end with a swift and firm smack from your heavy brass hammer. If it doesn't break loose on the first hit - you didn't hit it hard enough. Hit it again and this time like you mean it.

The sudden application of dynamic torque is far less likely to strip the threads, than trying to use a more progressive application of static torque applied by a breaker bar.

What's that you say? - you don't have large brass hammer either!

Go To: <a href=http://www.mcmaster.com/ TARGET=NEW> McMaster-Carr</a>

Enter Item Number: 5978A16 in the search box to the left.

You should see:

3lb Brass Hammer with wooden handle $36.84

Now with these two essential tools in your garage, you are ready to work on old Z's.


Carl B.

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If at all possible, (I had the SAME exact problem 2 weeks ago) Use a LOOOONG 6-point box end wrench. Typically, a combo wrench is gonna be a 12 point but 6 is WAY better.

1) 6 point box end combo wrench, LONG

1) Brass hammer or sand filled DEAD-BLOW hammer (Like a rubber mallet but hard plastic filled with sand.

1) another long box wrench to attach to the first one for added torque

1) the kroil works beautifuly

Good luck,


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I tried using some liquid wrench twice a day for a couple of days. I don't think it did any good. The kroil is in the mail...

I tried the mallet. But, that wasn't very effective because I couldn't hold the wrench steady while using the mallet.

I took my wrench and wrapped it with a ~1.5' aluminum pipe and wrapped that with a 1.0' aluminum pipe with larger diameter. BINGO! Easy as pie.

It looks like the bolt was overtightened to compensate for the omitted washer.

I replaced the 22mm bolt with a new 21mm bolt w/ washer that got from Autozone. I couldn't find any torque specs for the oil drain plug. So, I torqued it to 15 ft-lbs. Let me know if that is correct.

Thanks for all your help.

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