Stripped oil tank drain plug - help!

The drain casting on the oil tank is a separate part from the tank. In a worst case senario, you can just replace the entire oil tank drain casting. It is cheap at only $121 from Ricambi. This casting comes from the factory with a Heli-coil thread insert already installed in it. Are you sure that the threads in the drain casting are damaged, as they should be a helicoil wound from one piece of stainless steel. If it is the stainless helicoil that is damaged, you could pull the original out and install a new insert, as they are a separate part from Ferrari.

If the drain casting doesn't have a helicoil in it, I would repair the threads by installing a helicoil in it.
I don't like using time-certs in this application as the sealing surface for the crush washer must be machined with a step in it for time-cert, compromising the sealing surface.
Usually the problem that I see is that someone has over-tightened drain plug, stretching and distorting the threads on the plug. Have you tried screwing in a brand new factory plug? This is the first thing I try. Do not torque it to the factory spec and always use a new crush washer to avoid distorting the new drain plug.

 

Great advice Brian, I have had issues several times with drains plugs (usually a lot of resistance or felt cross threaded) where a new drain bolt/plug was the solution, as the threads had stretched from someone overtightening!

 

My "shadetree mechanic" advice is to tighten until you can just feel the washer start to crush (or yield) and stop. These aren't under great pressure and only need to be tight enough to not vibrate loose.

 

I have had god luck using a new spark-plug washer (if you can find them anymore, as they are now mostly tapered seat). They have a thick (and fairly soft) crush height, which can also tolerate more misalignment than a standard oil-pan sealing washer. As jakermc said, do not use a torque wrench, tighten until you feel the crush (or use an angle adapter on your ratchet to measure the deflection, but I do not have an angle spec)

 

It drives me crazy to read these kinds of threads.....people (reputable shops too) overtighten drain plugs all the time. You have to use a fresh copper crush washer EACH TIME or it will leak but people think you can just tighten it a little extra. It's a shame.

 

I always use a new crush washer and put some anerobic gasket sealant on the sealing surfaces (not the threads!). I then tighten the drain bolt until I just feel the crush washer yield. The drain bolt doesn't hold the car together and is not a structural part of the car. Most people tighten them up way too much, distorting the bolt and damaging the threads in the sump/oil tank. It just needs to be a little tight. I have never seen one loosen up in 50 years of working on cars.

 

No kidding ---- smear the new crush washer with sealant (I prefer Hylomar, myself), tighten down to snug finger tight..... then just a 1/4 to 1/2 turn with the wrench to seat. It's all you ever need, and you will never damage anything.

 

Also, think of how many times that drain bolt gets removed. Should be at least once a year, more if you drive the car. Those threads see a lot of use. It is not like a suspension bolt where the torque is critical and you maybe remove it twice in your ownership of the car.

 

3 weeks, how about 3 months for a second gear!

 

55 ft/lbs is way too much torque for that drain plug. As before, only tighten until the crush washer (with a smear of sealant on it) just yields. 55ft/ls is just crazy, no wonder the threads were damaged.
The drain bolt is usually the part that stretches when over-torqued, damaging the threads. Reusing the damaged drain bolt then damages the threads in the oil pan. If the drain bolt is tight going back in I usually replace it, because it has been damaged. The new drain bolt will thread right in.

 

Thanks for all the help. Still can't get over the Ferrari maintenance manual calling for 55 ft-lbs on that plug. Has me worried about the oil pan plug now as that one I am sure has also been over torqued for the last 15 years.[/QUOTE]

Where in the Ferrari maintenance manual is the torque spec for the drain plug? My work shop manual just says "-Tighten the caps again after cleaning them accurately and, if necessary, re- place the seals." I also don't see a torque in the torque specification pages.
Oh, I agree with the statement above, always use a new copper washer. I can't tell you how many oil leaks I have fixed with just a new washer that other shops did not replace.

 

Thanks, I was just wanting to know where in the manual it said that. I have looked before and clearly missed it. Those manuals always have some issue that makes no sense at times.

 

Ferrari manuals have a lot of errors. 5,5 should be the proper nm I presume...

Guido