NY Nick
NY Nick Dork
5/6/23 11:41 a.m.

My dad has a 1989 C4 vette and loves about 12 hours from me so I can't look at this myself. At some point someone cross threaded the oil drain plug. His Indy shop (who seems to be very good) attempted to retap it and put a new plug in. It is still leaking. Maybe 3-4 drops overnight. My dad is in his late 70's and has been around cars but I wouldn't say he is going to do a lot of mechanical work at this point in his life. A few questions;

1- are their repair kit options for drain plugs?

2- how hard is it to R&R an oil pan on a C4 vette?

3- the car sits from December to May every year. I'm thinking leave it for now, check the oil regularly and deal with it in January. E36 M3 your almost 80, how many more summers are you gonna drive your Vette around, don't loose time in it now. 

What say the hive?



zordak Reader
5/8/23 10:15 a.m.

Throw a piece of card board under it when parked. Drive it, enjoy it. You should be checking the oil every time you use it if not your daily. fix it on down time. Not sure but I believe the engine has to be pulled to do the pan, could be wrong.

OldDave New Reader
5/31/23 11:47 p.m.

here are your options:

take off and replace the bad pan with a new good pan. expensive and a giant pain in the A$$.

or, you can buy new oversize self tapping drain plugs in, 1OS, 2OS and even a 3OS, and hope you can cut the threads into the pan square enough to allow the seal full 360 deg. contact for a good seal.

on the above OS drain plugs, the big worry every time you drain the oil is that you don't booger up the new threads

which brings us to OS drain plugs with the head of the plug drilled and tapped for a 1/8"NPT brass pipe plug, you thread OS plug into the pan, and to later drain the oil, you hold the drain plug with a open end or box wrench and remove the pipe plug with ratchet and socket thereby not messing with the original pan threads.

which brings us to the ultimate solution, heli-arc a 1/2-20 grade 8 nut to the outside of the pan and use a brand new Chevy drain plug. did it on old winter beater Suburban I drove in the 70's.

and no matter which option you decide is the least harmful, find a 1/2" id brass/fiber crush washer about 1/8" thick, for a seal on the setup, it will look like a brass o-ring with a fiber filler, and a dab of #2 Permatex aviation sealer. a brown semi permanent sealer that never gets really hard. sorry if this got a little long winded.

bobzilla MegaDork
6/1/23 7:51 a.m.

No way you're getting that pan off in car. 3-4 drops a day? put a drip pan under it and move on.

NY Nick
NY Nick Dork
6/1/23 9:43 a.m.

Thanks for the input. So far he is just keeping a rag under it in the garage and enjoying the drive. I think that is going to be the direction for the short term. Maybe we will look at addressing it over next winter when the car sits for a long time. I really don't think it is an issue to worry about, he freaks out when it needs oil changes that it will be catastrophic. It only needs one a year and he takes it to a good indy shop for that and not a quick change place. I think he will be alright. 

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