looking for advise on drilling/tapping oil pan (c5) for 3/8 npt. instructions say to do it with oil flowing out. who has done that and how did it go? sounds pretty messy, especially without a lift. maybe a spiral flute* tap is a better solution? they are rare and quite expensive, though ($100+).

*edit: these are for blind holes and push the chips back up as opposed to a "gun tap" that pushes them forward.

 

Drain the oil and pull the pan off?

 

no, thanks.

 

Old trick I've used on various jobs is to get some air pressure in the crankcase . You can plug off all vents and or pcv openings and put air in the dipstick tube , I would use a low pressure regulator to start and once the hole is established go full flow the escaping air will blow out the cuttings made , Same when tapping but also pack the flutes of the tap with grease and remove , clean and repack often. Good luck

 

2 piece pan, by chance? Seems too obvious to ask almost….

 

Use a rotacut bit packed with grease to drill it, and pack the tap with grease. Go slow, and remove the tap often to clean/re-pack.

 

thanks. so nobody has done it with the oil comming out (as recommended)? this is on a c5.

 

Nope. That was the method I followed when I installed a A&A YSi kit, per their instructions. Pan was on the car, put 4-5k miles on it, never had a problem.

 

What’s the hole for?

Do you have the two piece pan? If so, remove the lower piece. Problem solved.

If not, I doubt doing it with the pan full would be any better than just drilling and tapping using grease on the bit and tap.

 

im not removing the pan for this. again, a&a instructs to do it with oil flowing out, josh confirmed it. so im looking to asses the mess it will make, oil running down your sleeves etc.

 

​​​​​​How much oil will come out of a hole in the oil pan... LOL! Think about it for a second, I know you got this one.

 

The grease method works well if you go slow, flush it with a couple of quarts of oil after the job is complete.