Oil drain bolt cross threaded help!

#1
Hello, well the last time I got my oil changed I took my Trooper to a shop (of course the only time in years I’ve taken my vehicle to any shop). Now doing an oil change 3k later I see my drain bolt is cross threaded badly- I knew something was wrong when I just cracked the bolt loose and oil started leaking through the threads. A few questions-

My factory plug (2000 Isuzu Trooper 3.5L) is a m14x1.50, the threads don’t look terrible in the oil pan. Can I just take a m14 tap to clean the threads out and pop in a Fumoto drain valve? Or should I buy an oversize m15x1.50 tap/bolt?

The shop was a very highly rated one but in Colorado and I’m now living in Michigan so I can’t really have them help...
thanks
 

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DaveInDenver

Expedition Leader
#2
I'd have guessed the bolt steel would be harder than the pan, so my expectation would have been the pan to lose that fight. But if the threads look intact try a thread chaser and not a cutting tap to clean them. You don't want to remove any more metal than need and use a new bolt. I'd probably install it without any oil to make sure it's going to hold. If that doesn't work I'd use an insert, e.g. a Helicoil or Time-sert, to keep it a M14.
 
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#9
To update- not a single drop has leaked. I used the supplied fiber washer and didn’t do much torque at all- maybe 10-15 ft lbs. all is good! Of course I’m working on a stripped transfer case drain bolt now that I messed up a timesert on.... JB steelstik is what I’m resorting to for that one and drill it out in 2-3 years
 

rayra

Expedition Leader
#10
I'm sensing a pattern....

Has no one ever taught you the trick of starting a bolt / plug by working it a bit COUNTER-clockwise until you feel it drop into the threads, then finger-tightening to make sure things are threaded properly before applying tools?
 

BigSwede

The Credible Hulk
#11
When I bought my 95 Trooper I was dismayed to find a rubber expansion plug in the drain hole for the transfer case. But it had clearly held for a long time that way so I didn't worry about it.

Then it fell out on Metal Masher trail in Moab. I didn't know it at the time, but I could actually hear a new noise coming from underneath on the way back to town (know thy rig...). I crawled under to investigate back in camp, and found the plug gone (and t-case empty, of course).

Somewhat amazingly, a small wrecking yard in Moab had a Trooper, I bought the t-case off of it and swapped the rear cover (which has the drain in it) over to my Trooper in a blinding sandstorm (or it just seemed like a sandstorm under there, either way it was windy as heck).

Not sure what the moral of my story is, but either way DON"T GO GORILLA WHEN TIGHTENING STEEL BOLTS IN ALUMINUM CASES.
 
#12
@rayra Yes I have been doing that for 10 years now, these are my first two stripped bolts I’ve dealt with! An oil change shop stripped my oil drain bolt(they were 1,000 miles away when I changed my oil again) and my t case bolt was due to offroading when I smashed the skid plate above the plane of the bolt, nearly shearing it off. That could have turned out bad....
 
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