I just bought a 2005 mustang and i was gonna give it a oil change. What is the blue stuff on the oil drain plug

 

Somebody put RTV on there probably to seal the bolt to the pan.

It's a gasket maker material that comes in a tube and dries rubbery and makes seals on things like water pumps and oil pans, and some of the manifold to engine block areas.

It is perfectly safe to remove just know that they put it there for a reason. Likely the drain plug leaked round the threads.

 

If I take the plug off and it leaks can I reapply rtv

 

If I want to reapply it what do i have to do. And do i have to buy the blue one

 

If you remove the plug and put it back without it and it leaks then in order to apply the rtv you'll have to remove the plug and waste all the oil you just put in.

You could also consider buying a new plug and installing it. The drain plug should have a small rubber ring or gasket of its own. I've had some older cars where this price failed after years of use and probably over tightening it causing it to tear.

Otherwise I would get the black rtv and put it a ring around the seat of the oil pan plug. Not on the threads! The black is better for oils than the blue. Or so I think I've been told.

 

Get a new drain plug and clean off the RTV, problem should be solved . . . but check for leaks just in case

 

Threads Merged . . . .

No need for two thread on the same topic.

 

That's my suggestion also. They're cheap enough.