I plugged the oil breather on my ‘70 F100 302...

Engine, ignition, fuel, cooling, exhaust

Moderators: Ranchero50, DuckRyder

Post Reply
Sisujoel
New Member
New Member
Posts: 7
Joined: Tue Sep 22, 2015 1:10 pm
Location: Red Wing, MN
Contact:

I plugged the oil breather on my ‘70 F100 302...

Post by Sisujoel »

... and now I’ve got oil blow-by spray on the passenger side of the engine compartment. :cry: The drivers side is clean and dry. I realize (after reading forum posts thinking I may have a leaking valve cover gasket) that I made a boneheaded :roll: mistake by plugging the breather cap. The breather cap is original and I learned that it would’ve originally had a hose routed from it to the air filter cover. When I acquired the truck it had no breather hose and a mismatched air filter cover so I installed an aftermarket open flow style air filter holder.

Questions: what possible damage might I have done by plugging the breather cap? Fortunately I only drove the truck a couple times for short distances before noticing the oil spray. What would be the most likely source of the passenger side oil leak/blow back? Valve cover gasket? Since I don’t have an original air filter cover to route the breather cap to should I replace the original cap with a mesh filter style breather cap?

Live and learn. :help:
User avatar
Jacksdad
Blue Oval Fan
Blue Oval Fan
Posts: 579
Joined: Sat Mar 30, 2013 8:52 pm
Location: San Diego, CA

Re: I plugged the oil breather on my ‘70 F100 302...

Post by Jacksdad »

I guess there's always a chance you could damage a seal or unseat a gasket, but you probably didn't do anything other than make a mess.
1971 DRW F350 cab and chassis with an Open Road motorhome conversion, Dana 70, 352 (originally 390)/C6, PS, power front discs, and 159" w/b.
Busboy
Blue Oval Fanatic
Blue Oval Fanatic
Posts: 943
Joined: Sat Jan 24, 2015 9:51 am
Location: Nampa Idaho

Re: I plugged the oil breather on my ‘70 F100 302...

Post by Busboy »

There would be no permanent damage but it sounds like the engine is toast with that amount of blowby.
1967 F-100 4x4 custom cab.
Another 67 F-100 4x4 custom cab.
2016 F-150 Eco-Boost 2.7 liter. (It will smoke the tires!)
1972 F-350 Sport Custom cab & chassis.
1972 F-250 Explorer Special, Camper Special.
1971 F-100 custom. 302, C-4, p.s. p.b. factory 65 amp alternator with transistorized voltage regulator.
tnlprt
Blue Oval Guru
Blue Oval Guru
Posts: 1144
Joined: Thu Jul 08, 2010 5:18 pm
Location: St Louis mo

Re: I plugged the oil breather on my ‘70 F100 302...

Post by tnlprt »

The original breather cap had the hose routed to the air cleaner for only one purpose.
To filter the air being sucked into the crankcase

A mesh or K and N style breather will work just fine.

Likely no damage occurred.

Blow by is a product of ring seal ..Live with it or rebuild it

The most you have done is blown the valve cover gasket or the end seals on the intake . Hope for the valve cover gasket.
Sisujoel
New Member
New Member
Posts: 7
Joined: Tue Sep 22, 2015 1:10 pm
Location: Red Wing, MN
Contact:

Re: I plugged the oil breather on my ‘70 F100 302...

Post by Sisujoel »

I appreciate the replies. Lesson learned.
Post Reply