1992Corvette

Hello, I am having an issue trying to find the correct oil drain plug for my 1992 corvette with the LT1, vin P car. When I went to my local Chevrolet dealer ship to purchase one the guy on the parts counter checked and found that there were two different plugs used for this year. He advised me that one would be a metric plug, which he says is what's typically found. Other would be a standard drain plug, 1/2" x 20" thread. I looked it up online and am coming up with 3 part numbers. One is a 1/2" x 20" thread, a 5/8" x 18" thread or a M12x1.75. Does anyone know what plug is supposed to be used as the oil drain plug on a 92 corvette 5.7L vin p? If anyone has a book and can give me some insight on this I would really appreciate it. I'm just stuck now. Also, if there was two different plugs used for this year can anyone verify what the two plugs are and what size were they? If I can at least find this much out then I should be on the right track to correcting this. The previous owner installed a drain plug that is not correct for the car. It threads in but it leaks oil. I purchased the metric plug as the dealer said it is typically what's used but it was not the right size. Any help on determining the oil drain plug size would be great! Thank you!!

Joe C

(just my parts boy 2-cents - FWIW) according to the factory parts manual, the PN is 3921988, and called out as 1/2-20. seems like there is also a gasket, PN 14090908. from what I can tell, it has many GM applications.

WVZR-1

If it's the original oil pan and not a replacement it should be the 1/2-20 with a gasket, a service pan could be the metric spec the dealer mentioned BUT the other spec you found is for the ZR-1/LT5.

The PO may have stripped the original and done something "oversize" and maybe created the leaking issue. Buy the 1/2-20 and a gasket, if you can't thread the 1/2-20 by hand finger tight or it wobbles some then the PO has done something "creative".

1992Corvette

Thank you for your response. I'll get a 1/2 x 20 and give it a try.

Hot Rod Roy

You may only need a new gasket! I've had the best luck with new gaskets by making my own. The most durable, leak proof gasket material I've found is a plastic ground coffee container. Just the right thickness, and tough as nails! Drill the right sized hole for your drain plug first, then cut the outside diameter concentric to the hole.

whalepirot

, assuming the threads are good.

Christi@n

1/2-20 about the thread?? Bolt head is always 14 or 15mm don't remember
right one....

Mine was 14 or 15

DGXR

oops... deleted

reg_255

Here is the part number for the oil drain plug gasket 14090908.

Regards,
Roy

1992Corvette

Thank you to everyone who has responded. Now I have some information to get me started. I really appreciate the help! Thanks guys!