Senior Tech Team
Join Date: Aug 2002
Location: Gold Canyon, AZ
Re: What sealent to use on freeze plugs and oil galley plugs?
those manufacturers, wonder if they work on 40 year old blocks much?
Excellent observation . . . . . . and yes, they do.
My contact with freeze/expansion/core/Welch plugs was during my tenure in the Product Planning department of one of the largest (OEM & aftermarket) automotive parts manufacturers in the industry. Our concern was exactly the same as yours and we were (and still do) field many calls concerning expansion plug failure. We all know that these plugs are installed in bores that may be of questionable physical condition and the installation process is possibly undertaken in the very poorest of conditions (like underneath a tractor in the middle of a field).
The consensus of the plug manufacturers (who supply both the OEM and aftermarket) was that the hole must be cleaned and dried as well as possible before installation. The affect of any type of sealer is totally useless even if there are pits in the bore. Severe pitting and gouges should be treated with corcus cloth or sandpaper, but if the plug is going to fail it will do so whether or not sealer (goop) is used in the installation.
Just reporting the facts . . . .
64 Chevelle Malibu Sport Coupe (original owner) car now has 427" BB, Jerico 5-spd. trans., Dana 60 rear end.
SAE Member (25+ years)
ASE Master Certified Engine Machinist
AERA Certified Professional Engine Machinist
Last edited by engineguy; Mar 3rd, 08 at 1:35 PM.