Oil drain plug leak....?
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
Oil drain plug leak....?
Been trying to figure this ever-so-slow oil leak. Tiny drops surround the drain plug and spots the floor. Takes a few days to show up on the plug and floor after wiping clean. Changed the drain plug to a new one last fall, but same results.
Since this car is so low to start with, I wonder if previous owner may have slightly hit the front of the pan or plug just enough to mushroom the pan around the plug, and maybe the plug doesn't tighten up flush?
Anyone had this issue? Leak is definitely from plug area.
Since this car is so low to start with, I wonder if previous owner may have slightly hit the front of the pan or plug just enough to mushroom the pan around the plug, and maybe the plug doesn't tighten up flush?
Anyone had this issue? Leak is definitely from plug area.
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
It sounds like the sealing surface, on the pan drain tapping itself, is not smooth and flat.
Try a soft copper sealing washer on the drain plug in place of the rubber seal.
Try a soft copper sealing washer on the drain plug in place of the rubber seal.
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
Last fall during the oil change and plug change I believe I only concentrated on the plug, as I dont recall seeing anything unusual with the pan. Will be changing oil soon, so inspection of the pan will be next. I'm thinking its "sort of mushroomed or slightly crunched" just enough to not seal correctly, otherwise I have no clue what it could be.
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Drifting
Joined: Jul 2006
Posts: 1,490
Likes: 257
From: Lake Tapps WA.
Last fall during the oil change and plug change I believe I only concentrated on the plug, as I dont recall seeing anything unusual with the pan. Will be changing oil soon, so inspection of the pan will be next. I'm thinking its "sort of mushroomed or slightly crunched" just enough to not seal correctly, otherwise I have no clue what it could be.
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
The plug has straight threads, not tapered threads like pipe fittings have. Teflon tape works best on tapered threads.
A thin coating of black silicone RTV over the rubber seal, before you install the plug each time, should stop the drip too.
A thin coating of black silicone RTV over the rubber seal, before you install the plug each time, should stop the drip too.
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
but there must be something wrong if that is necessary?
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
There has to be a casting flaw or an irregular surface in the lower oil pan section, at the drain plug hole tapping. You'll have to drain your oil to do a close inspection of the area.
Look for any nicks or burrs in that area, and remove them with a Dremel tool.
Look for any nicks or burrs in that area, and remove them with a Dremel tool.
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
Well...the leak is back.....
..after draining oil, and inspecting pan a few months ago, I delicately filed the surface around the hole to ensure the surface was flat...installed new drain plug with seal. About a week ago started smelling the oil again ever so lightly sprayed over the bottom of the oil pan. Yet this time, no drops on floor. Smell is worse the more I drive especially at highway speeds.....is it time to change oil pan????
..after draining oil, and inspecting pan a few months ago, I delicately filed the surface around the hole to ensure the surface was flat...installed new drain plug with seal. About a week ago started smelling the oil again ever so lightly sprayed over the bottom of the oil pan. Yet this time, no drops on floor. Smell is worse the more I drive especially at highway speeds.....is it time to change oil pan????
Drifting
Joined: Jul 2006
Posts: 1,490
Likes: 257
From: Lake Tapps WA.
Well...the leak is back.......after draining oil, and inspecting pan a few months ago, I delicately filed the surface around the hole to ensure the surface was flat...installed new drain plug with seal. About a week ago started smelling the oil again ever so lightly sprayed over the bottom of the oil pan. Yet this time, no drops on floor. Smell is worse the more I drive especially at highway speeds.....is it time to change oil pan????
..after draining oil, and inspecting pan a few months ago, I delicately filed the surface around the hole to ensure the surface was flat...installed new drain plug with seal. About a week ago started smelling the oil again ever so lightly sprayed over the bottom of the oil pan. Yet this time, no drops on floor. Smell is worse the more I drive especially at highway speeds.....is it time to change oil pan????
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
When I changed my oil I cleaned off the teflon tape and put on a thicker O ring. That solved it for me. You could also try "Gasket Eliminator" on the threads or maybe the oil is coming from somewhere else and running down to the plug? You probably already checked that tho.
Race Director
Joined: Oct 2006
Posts: 13,404
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From: Glastonbury CT.
St. Jude Donor '11-'12-'13-'14-'15-'16-'17,'20, '21,'22, '23
An idea...........Use a tap to restore thread or create new thread or buy a specially made oversize drain plug from an auto parts dealer. The one you want is designed to rethread damaged threads in the oil pan, allowing the new plug to seat properly and seal the leak. Start the plug into the drain hole by hand, and then use a wrench to seat the plug. Stop turning as soon as the plug is secure.
Different seals/washers require different torque requirements, depending on the material they are made of; do not overtighten...do not undertighten.
I have heard chrome plugs work best.
777
777
Different seals/washers require different torque requirements, depending on the material they are made of; do not overtighten...do not undertighten.
I have heard chrome plugs work best.
777
777
Thread Starter
Le Mans Master
Joined: Jun 1999
Posts: 5,548
Likes: 41
From: Conn.
St. Jude Donor '21
All these ideas are good ones, but have been tried.....I am almost certain oil pan must have been "mushed" at one time by previous owner thereby causing the drain hole not to be round (cannot see this by eye, BUT- there is a "flat spot" at the very bottom of the hole in the pan..)not sure if this was cast this way or been hit......
the drip is so slow it takes weeks to appear...maybe trade this in for a C6....
the drip is so slow it takes weeks to appear...maybe trade this in for a C6....
Le Mans Master
Joined: May 2007
Posts: 5,393
Likes: 17
From: Belleville Mich.
All these ideas are good ones, but have been tried.....I am almost certain oil pan must have been "mushed" at one time by previous owner thereby causing the drain hole not to be round (cannot see this by eye, BUT- there is a "flat spot" at the very bottom of the hole in the pan..)not sure if this was cast this way or been hit......
the drip is so slow it takes weeks to appear...maybe trade this in for a C6....
the drip is so slow it takes weeks to appear...maybe trade this in for a C6....
There you go. Problem fixed!!
