OK...

So either from the previous owner or the oil shops she took it to, the bolt head corners were rounded off when I bought the car. Having trouble getting the plug off, I decided it was probably smart to go to Honda to buy a new plug first.

Upon getting the plug out (with a lot of work), I realized that the new plug was shorter plug (less threads). Otherwise the plugs looked identical (minus the rounded corners on the new plug).

Anyway, I've used this plug since then with no problems in any of the many oil changes over the last 90k miles.

Today, however, the plug did not just thread out once loosened as usual. I didn't have to use alot of force, but I did have to use the wrench to back the bolt out. After draining the oil, it appears as though the threads that contact this particular (shorter) plug are stripped. I did actually have some of those threads come out with the plug. I will say with absolute certainty, the plug was NEVER cross threaded. I always put it in by hand until the head contacts the pan.

Anyway... So now what are my options (and related costs)? With all the cars I've owned, I've always changed my own oil, and I've never had this type of problem, so this is new for me. New oil pan? Re-thread and new bolt? Would a new, longer plug be sufficient, at least short term (until next oil change)?

Any help would be extremely beneficial, as this is my daily driver, which needs to be back on the road by Sunday evening.

Thanks...

 

I wouldn't rush the repair, especially for something as critical as the oil drain bolt. There are several solutions, based on some speculation about the condition of your oil pan. From the condition of the previous oil drain bolt (rounded corners) and your report of aluminum threads coming out when you backed off your recent short bolt, some damage has occurred to the oil pan. If you're lucky, it's only the last few threads that stripped off and installing a correct length bolt will allow it to engage threads deeper in the oil pan and it will hold the correct amount of torque (about 35 lb-ft). Be sure to use a new washer to maximize sealing capabilities. I would consider this a TEMPORARY solution and would make sure to do a permanent repair as soon as possible.

However, if it were my car, I'd never trust to luck something as important as keeping oil in my engine. There are 3 solutions that I would consider permanent; they are listed in order of my preference:
1) Heli-arc weld new aluminum marterial into the damaged hole and have it re-threaded for a standard size oil drain bolt. For this procedure, the oil pan must be removed from the engine (not that difficult, but it would take some time).
2) Install a helicoil or other type of threaded insert. The drain bolt hole must be drilled slightly oversize, rethreaded and scrupulously cleaned for insertion of the helicoil or threaded insert, making sure that the correct assembly compound is used to lock the insert into place. Then the standard drain bolt and washer can be used.
3) Have the drain bolt hole tapped oversize and use an oversize bolt with correctly matched threads and oversize sealing washer. This solution is relatively simple, but not convenient since special sealing washers must be sourced and your mechanics will have to be told about the special bolt.

If you follow suggestions 2 or 3, after the machine work, make certain that all metal is removed from the engine. It is safer to do these repairs with the oil pan removed, but not required is the correct cleaning is perfomed.

Good Luck!

 

Another "temporary" fix used to be available at some of the auto parts chains. It was a piece of rubber that had some way of being kept in the oil plug. I used one a very long time ago in a POS Pinto that had a striped oil pan.

I don't know if they still make this sort of thing. I definitely wouldn't keep it in the S2000 any longer than you had to, but it is a quick and dirty fix that will get you back on the road until you have time to do it right.

Good luck!

John

 

I'd run a metric tap of the appropriate pitch/thread through there first. You might be able to drill it out and Helicoil it, but that would be if all else fails. A good machine shop with an experienced welder could likely drill out the area and weld on a new bung.

 

Nah, just use a crush washer, but first stick an unfolded paperclip into the hole, then insert the drain plug and tighten. Overtorque it and snip off the excess.

 

 

My first oil pan was bad from the factory and I had the threads come out in the first oil change - not a good start for my car. Nevertheless, the oil pan is not at all hard to change out - this won't help you out Sunday, but it should give you a little piece of mind.
Remember, if metal came out with the plug, there's a good chance there's some in the pan. I didn't even think about starting my car when this happend to me. It happend on a Friday evening - I had the car flatbedded from the auto hobby shop on base to my house (for the weekend), and then flatbedded to the dealership that Monday. It was under warranty, but the bill was around $340.00 for the pan and the install (charged to Honda). If you do it yourself, you can find the pan online:

http://www.hondaautomotiveparts.com/auto/j...R+BLOCK-OIL+PAN

It goes for ~$180.00. The pan gasket is Honda grey RTV (Honda Bond).

 

tighten it till it strips, then back it off a 1/4 of a turn

 

buy a new oil pan

 

http://www.jdmgears.com/Spoon_engine.htm


maybe an aftermarket oil pan while you're at it??