5.0L oil drain plug issue

[Gsmblue]

Last spring I was lazy and took my F150 to a quick lube place for an oil change. This year as I’m doing all my oil changes I pulled the drain plug and this is what I see - half the threads are stripped.





The bolt head says 1/2–20 so I go to the store and get another one, but The diameter of the threaded part is significantly wider than the old one. I’m not sure if this is just because it is new and has not been stripped, but I’m being very cautious as it didn’t seem to want to go in very easily and started binding.

I tried putting the original stripped one back in but it was not going well so backed it out.

What a mess!

Any suggestions on how to proceed?

[Gary Lewis]

The MPC says your engine's drain plug should be PN D6TZ 6730-A.  But it doesn't say what size that is.  However, CJ Pony Parts says that is 1/2" X 20.

So you have the right part.  Given that, I'd make sure you aren't cross threading it and then put it in.  Hopefully it'll go in nicely, but something is wrong with the threads given the look of the stripped drain plug, so it stands to reason that it will require some re-cutting of threads.

[82F150I6]

I had the same issue on my 4.9L earlier this year (except that I change my own oil so I can't blame it on a quick lube place).  In fact, your drain plug looks eerily similar to mine.  I checked the specs and determined my plug was 1/2"-20 threads so I bought a Dorman replacement from AutoZone.  I didn't have a 1/2"-20 tap so I figured, what the heck, and carefully started the plug into the oil pan drain hole.  At first I needed a wrench to tighten the plug but after a bit it became easier and I was able to hand-tighten the plug then use the torque wrench on it.  This was a few months ago and so far no leaks.  It remains to be seen what happens for my next oil change, but I'll take the win (for now).

As always, YMMV.  Good luck.

-Walt

[Gsmblue]

Thank you!

The old one was labeled 1/2–20 so I tried using a new one that I had to correct the threads, but it really bound up bad so I stopped.

I ended up going to Ace Hardware and I bought a tap and carefully re-threaded. Once I had done that I tried using the new 1/2–20 drain plug, then I realized the threads have been stretched and I couldn’t use it so, I had to go to the store again and get a new one.

I also picked up 2 quarts of cheaper oil and a magnet that extends so I fished around in the oil pan getting as much metal as possible, then flushed through with 2 quarts of the cheap oil, installed the new drain plug, which went well, then the 6 quarts of good oil went in. Then all seemed well with the world.

4.5 hours and six trips to various stores! But she’s all sorted and I won’t be lazy in the future. I will do all the oil changes every spring no matter what!

*corrected many typos!

[Gary Lewis]

Well done!  That's the way it should be done.  

[viven44]

Whats the torque spec on these bolts anyway ? If I recall correctly it is about 15-20ft lbs. They must have seriously torqued it down to strip those threads.

[Gary Lewis]

From the Windsor section of the shop manual (Documentation/Engines/Windsor) it 15 - 25 ft-lbs.

[Gsmblue]

Thanks Gary, I will torque it down.

I also did an Oil Change on Espy - that went far more normally..

[Gary Lewis]

[viven44]

I often find that the specified torque (in just about anything) is higher than what I think it should be based on feel. I usually look at the torque spec just to get an idea of what the application is expecting torque-wise and just use feel (except for critical items like bearings, wheel/axle studs).

In this case... most 3/8 and 1/2 inch wrenches cannot accurately hit 20 ft-lbs. If you have a 1/4 inch torque wrench you can hit the lower end of the spec here (usually those can go up to 16 ft lbs) and that should be more than sufficient..... just in case the threads in the pan are weak ;/

[85lebaront2]

Biggest issue with oil change places is speed. they want you in and out fast. One near me when I was in Newport News I called their bluff. They wanted to due a "full service" on Darth including a fluid and filter change on the C6. Kid told me there wasn't a converter drain. I told him I would make a bet on it, if I was wrong I would pay double for the transmission service, if I was right it would be free. He didn't bite.

I had previous issues with them, like breaking a vacuum tee on my 1981 Omni while the greased the upper ball joints on it (Macpherson Struts, no upper ball joints).

I did get them one time, I took our 1955 Packard Patrician in. car had probably 25-30 grease fittings, an oil bath air cleaner and a bypass oil filter. I copied the lube chart from the service manual so they could see where the grease fittings were. I was told, we don't even have a listing for air or oil filters for that car. I handed him the new oil filter element and explained oil bath air filters to him. They actually did the full service on it.

[mat in tn]

my old mechanic would say "tighten it to a fair handshake" remember, the threads are already well oiled.