Blow-by problems....
Thread Starter
|
Freshman User
Joined: Jul 2005
Posts: 38
Likes: 0
Blow-by problems....
Ok, I have an 81 f150 with the 300 I6. It's got a bad case of blow-by. The owners manual, and a few people on here, say to check the entire pcv system and the egr system. The pcv checked out fine, except there is no vaccuum in the valve cover when I removed the oil filler cap (like the manual says there should be). The manual says if no vaccuum is present, the pcv is bad. I took it off, replaced it, cleaned out the hoses, and still no vaccuum. So, I go to check the egr and the damn plastic fitting that the vaccuum line connects to on the egr broke (kinda besides the point). Should there be a vaccuum coming from the hose, or the egr valve? If it checks out fine, what would be another thing to check? I've never had to deal with blow-by before, so it's obviously sort of a new thing to me. Thanks in advance.
Senior User
Joined: Apr 2003
Posts: 243
Likes: 0
Egr, I don't think will bother your blow-by, but vacuum comes from the hose. You'll probably have to increase rpms to get any vacuum.
As for your blow-by, increase engine speed to check vacuum at oil fill tube. The vacuum will not be very noticeable. Infact, it'll be worse if you have internal problems. Bad valve, valve seals, leaking around rings, hole in piston, etc. Not to scare you, these are just probablities.
In other words blow by can't be made up with the PVC. The air being pushed from leaking compression will outweigh the vacuum being created by PVC.
Good Luck. I see moderator, moved your post. You'll get better response down here for your motor.
As for your blow-by, increase engine speed to check vacuum at oil fill tube. The vacuum will not be very noticeable. Infact, it'll be worse if you have internal problems. Bad valve, valve seals, leaking around rings, hole in piston, etc. Not to scare you, these are just probablities.
In other words blow by can't be made up with the PVC. The air being pushed from leaking compression will outweigh the vacuum being created by PVC.
Good Luck. I see moderator, moved your post. You'll get better response down here for your motor.
Junior User
Joined: Feb 2005
Posts: 56
Likes: 0
From: Parma Heights, Ohio
yes, do a compression check, then do a compression check with a little oil in the cylinders.
i think the specs are, that the lowest cylinder should not vary more than 60% of your highest cylinder.
i think the specs are, that the lowest cylinder should not vary more than 60% of your highest cylinder.
Thread
Thread Starter
Forum
Replies
Last Post
xjcamaro89
2004 - 2008 F150
22
Sep 2, 2021 11:30 AM
fivestring63
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
4
Feb 18, 2006 07:39 PM
