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Tapping drain plug

M

Mhester1

Member
Ran across this forum while searching for my tapping problem
My vehicle has a plastic drain pan and a plastic drain plug which the oil change shop stripped out. Unfortunately it’s a huge plug M24x1.5, so commonly found oil plug problem solvers are not large enough. However At a truck diesel parts place I found a jumbo sized drain plug solver with a valve to let the oil flow out such that the plug never need be unscrewed. It’s a M27x2

I have no experience tapping holes but assumed plastic would be simple enough.
Question is whether I can successfully put a M27x2 tap into stripped out M24x1.5 hole.
Any and all input is greatly appreciated. I’m currently leaking at least a quart a week... need to fix this. The other alternative I’ve found is tapping a M26 since I did find a steel replacement M26 plug (just a plain plug with no drain thru feature) but if the M27 is too big to tap into the M24 hole then maybe that’s the other route. I’d prefer to install a plug that never moves again that way I won’t have to be so careful about who I let touch my vehicle (it sits very low and has a splash shield so changing my own oil is not the easiest task otherwise I would DIY it) Thank you.
 
Pic of the drain valve plug
 

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Ok I’ve found a M25x1.5 valve plug online. Assume that it makes more sense to tap a M24 to a M25 - correct? There’s also a M26 sized one.
 
Mhester1 said:
Ran across this forum while searching for my tapping problem
My vehicle has a plastic drain pan and a plastic drain plug which the oil change shop stripped out. Unfortunately it’s a huge plug M24x1.5, so commonly found oil plug problem solvers are not large enough. However At a truck diesel parts place I found a jumbo sized drain plug solver with a valve to let the oil flow out such that the plug never need be unscrewed. It’s a M27x2

I have no experience tapping holes but assumed plastic would be simple enough.
Question is whether I can successfully put a M27x2 tap into stripped out M24x1.5 hole.
Any and all input is greatly appreciated. I’m currently leaking at least a quart a week... need to fix this. The other alternative I’ve found is tapping a M26 since I did find a steel replacement M26 plug (just a plain plug with no drain thru feature) but if the M27 is too big to tap into the M24 hole then maybe that’s the other route. I’d prefer to install a plug that never moves again that way I won’t have to be so careful about who I let touch my vehicle (it sits very low and has a splash shield so changing my own oil is not the easiest task otherwise I would DIY it) Thank you.
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I'm sorry I dont have an answer for you but I do have a question if thats ok....what sort of vehicle has a plastic drain pan and plug nowadays?
 
Mhester1 said:
Question is whether I can successfully put a M27x2 tap into stripped out M24x1.5 hole.
Click to expand...

I cant help you on your specific application but I think its advisable to use the correct drill size for a tap/pitch combination, because that dictates proper thread fit. For reference this table says 22.5mm drill for M24x1.5 and 25mm drill for M27x2. So by the book, the difference in diameter is (25.0-22.5)=2.5mm = 0.098" Stripped is a relative term but that's a pretty big difference IMO. Even though its a big hole, the threads are relatively fine, so pilot hole sizing is important.
https://fullerfasteners.com/tech/recommended-tapping-drill-size/

Having said this, plastic can be weird material to tap depending on lots of variables. Rigid plastic cuts similar to metal, but soft ductile plastics can distort & expand, potentially only cutting partial threads. But the flip side is it might be elastic to the point it contracts & seals despite this. Put it this way, I wouldnt gamble if it was something important. Maybe there is a way you can test on something expendable.

Also are you talking buying a tap or somehow using the fitting to self tap? (Reason I mention is taps like this can be spendy for a one time use & the second point is generally not advisable). Hope this helps!
 
My experience re-tapping out shallow holes has not been good. You must ensure your have solid material to tap into and that means drilling out the existing threads completely, which means going up multiple sizes to achieve this, especially in a situation where you cannot mount the part to ensure a perfectly perpendicular drill and retap.

I can't imagine doing this on an oil pan, let along plastic. Sorry.

Too bad you couldn't use a nutsert/rivnet and then heat it to form the plastic around the metal. I did that once on a fertilizer tote but you have to have the right plastic and be willing to gamble. The JiffyLube kids would probably torque it out of place anyways. They love using those air wrenches on everything.
 
Is your pan off? any idea how thick the pan is where the thread goes through?

Co-worker had a (new to him) VW Golf that had a stripped drain plug from a quick lube shop, they had cover the cost of a new pan.
 
To figure out roughly what size hole you need for a given thread. subtract the pitch from the nominal diameter. Example. 25x1.5mm metric tap needs a 23.5mm hole to start. If your 24mm thread is stripped i would buy a 26x 1.5mm and see if you can make that work. It won't be perfect but that will be close
 
Chicken lights said:
Those things are considered a bad idea on trucks, they are very exposed and if anything ever knocked it open while driving you’d never know until you lost oil pressure. My opinion anyway
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I agree emphatically ... all it would take is a couple unlucky stones from a front tire to open that petcock.

My one & only fix for that problem would be remove the pan & fashion a two layered pinch plate & gaskets inside & out with a steel pipe thread collar welded to the bottom/outside plate.
 
kevin.decelles said:
That takes me back to 1986 and a ‘77 Chevy Nova with a broken manifold

Thank you, that made my night....
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What is it about Novas that just scream jerry rig? My friend bought a beater Nova in high school. So much junk it had to be towed to his house. Wouldn't start for anything. One day we were playing with it and I noticed there was no gas getting to the carb. Crawled under it and discovered the gas line had rubbed against another line and couldn't hold vacuum. He just wanted to hear it start so I cut out the damaged line, added a two inch section of windshield fluid hose with some clamps to replace it temporarily just so he could start the pile of bones. It started alright. He ran that car for 2 years with the patch. Every time he punched it the car would stall because the rubber hose would collapse on itself, starving the carb. But it did have a great stereo.

Man were we stupid. Sadly, it wasn't the dumbest thing we did either. This is why women live longer than men.

Having said that, I feel like the proverbial, "Back in my day..." guy. No even sure if JB Weld existed when I was 18. I've heard it is tappable when fully cured. Plastic oil pans? Tappable epoxy? Boy have times changed.

Best of luck to @Mhester1
 
historicalarms said:
I agree emphatically ... all it would take is a couple unlucky stones from a front tire to open that petcock.

My one & only fix for that problem would be remove the pan & fashion a two layered pinch plate & gaskets inside & out with a steel pipe thread collar welded to the bottom/outside plate.
Click to expand...

If I am not mistaken those drain valves have plugs you put in them after you shut them, that way if they open they will still not leak oil out of them. Also you need to lift the lever up, then over to open them. Not as easy as it sounds as the lever is spring loaded to push down and stay shut. Now in saying all that, I would still be hesitant to use one, for the fact I drive a lot of gravel and off road. But if I was a city guy, or highway only driver I wouldn't worry much.
 
Using any size tap to thread the hole is unlikely to work as the oil pump pick-up will be very close to the bottom of the oil pan where the drain plug is. The tap will not enter the threads far enough to be effective without hitting the pick-up screen unless you have both a taper tap and a bottoming tap. You should look through the hole carefully with a good light to see what obstacles the tap might encounter before trying it.
 
What is it about Novas that just scream jerry rig? My friend bought a beater Nova in high school....

Oh you rich Nova kids and your radiator/water cooled engines LOL. I was the idiot driving a VW scraping frost from the INSIDE of his windshield HaHa. I found a gas (as in gasoline) heater from a wrecker. Likely designed by the same VW engineer that came up with pressurizing the windshield squirter from the spare tire. After a day of metal butchery with hand drill & file, got the heater installed & hooked up the lines. Red to red, black to black, who needs the yellow wire anyways LOL. Turned it on & was rewarded with nice 'leg browning' heat. Ahhhh this winter is going to be DIFFERENT! As I was cleaning up feeling so proud, it started to make increasing woofing sounds like a steam locomotive & growing flame pulses visible on the outlet. I decided the cost of burning my dads garage down outweighed me being cold. Sorry for the digression, we could probably fill a forum with fond memories. Back to threads...
 
DPittman said:
I'm sorry I dont have an answer for you but I do have a question if thats ok....what sort of vehicle has a plastic drain pan and plug nowadays?
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It’s a BMW 428i. Hard plastic of course. I think maybe some other vehicles may have them too nowadays.
 
Chicken lights said:
Those things are considered a bad idea on trucks, they are very exposed and if anything ever knocked it open while driving you’d never know until you lost oil pressure. My opinion anyway
Click to expand...

there is a splash shield so that’s not an issue. But even w/o that there is no way a rock is going to turn the valve handle the way they have designed these things. It’s done well with a spring lever that must be pushed “up” and the turned 90 degrees from the initial push motion. Completely safe and there’s even a screw on cap on the outlet too.
 
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