The message to which you are about to reply is shown first. GO TO REPLY FORM



 VIEW    REPLY TO THIS MESSAGE Replies to this message will be emailed.    PRINT   SAVE 

B21 Vacuum problems? on 79 GT 200

posted by  Don Foster on  Tue Feb 18 03:32 CST 2003
Author: [PROFILE] [EVERY POST] [THREADS] [BEST POSTS] RSS Feed     [IGNORE ALL POSTS]
last visit: Sun Oct 5 11:53 CST 2014
[RELATED]

I suspect that the ventilation hose connected at the airbox experiences a very slight vacuum, which is created by the pressure drop across the air filter as the engine breathes. But now, yours not only doesn't have that slight vacuum, it instead may have a slight positive pressure. This slight pressure can occur from the restriction caused by the extra filter -- the pressure increase will depend on the flow rate.

The "PCV," as you call it (it's really called the "flame trap"), has a small vacuum line, about 1/4" OD, that connects to the top of the "Y" fitting. The other end attaches to a small brass nipple on the intake manifold. That hose and the fitting are notorious for plugging with carbonized varnish, blocking the vacuum.

Be absolutely sure that the oil spearator (aka "breather box") and the flame arrestor (inside the flame trap) are clear. If either plugs up (not uncommon, particularly on a car that had neglected service) then your crankcase will develop enough positive pressure to blow oil past all the seals, and even pop a seal outta its housing (BTDT).
--
Don Foster (near Cape Cod, MA)






USERNAME
Use "claim to be" below if you don't want to log in.
PASSWORD
I don't have an account. Sign me up.
CLAIM TO BE
Use only if you don't want to login (post anonymously).
ENTER CAPTCHA CODE
This is required for posting anonymously.
OPTIONS notify by email
Available only to user accounts.
SUBJECT
MODEL/YEAR
MESSAGE

DICTIONARY
LABEL(S) +
IMAGE URL *
[IMAGE LIBRARY (UPLOAD/SELECT)]

* = Field is optional.

+ = Enter space delimited labels for this post. An example entry: 240 muffler


©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.