• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Engine Oil In The Intake Via Pcv Solved... Really

  • Thread starter Thread starter theYman
  • Start date Start date Sep 9, 2015

theYman

Active Member
Jun 5, 2013
88
24
29
Sep 9, 2015
#1
  • Sep 9, 2015
  • #1
I have researched this topic extensively and have tried multiple fixes. I have used an oil separator, full length intake baffle, larger lines, etc. None of them were 100% successful until now.

I was reading another post from 2006 and the original poster claimed success with this same setup, so I tried it,and it flat out works. I would give him/her credit but I can not find the post now.
It involves using 2 pcv valves ( I used the Lightning pcv) elevated away from the intake. The pcv in the intake is replaced with a 3/4" male to male fitting, then a section of 3/4" heater hose mine is 3", into a 3/4" T, a hose on each side of the T joins 3/4" 90's, then another hose that house the pcv valves on each side. Then the pcv's 90 fitting are connected to each other via a 3/8 T fitting.
Finally, the other leg of the 3/8 T is connected to the line that goes into either your intake vacuum or your oil separator. I kept my separator to monitor if any oil makes it that far, so far none has.
After multiple full throttle blasts I have yet to see any oil in my separator or out the exhaust. Before this mod, my car would smoke after a long idle time and a WOT blast. I have included a diagram that I made to help explain it and picture of my setup .
I have also checked crankcase pressure/vacuum to be sure there are no difference between a single/dual pcv set up. In both situations with my vacuum/pressure gauge attached to my dipstick tube the reading were identical at 2"HG vacuum.
The theory of using 2 pcv's is to decrease the velocity while maintaining the volume of air. Less velocity will carry less oil.
With this mod my car seems to have a deeper exhaust tone, It also does not smoke at all , and the oil separator is bone dry.
 
Reactions: A5literMan, RangerJoe and jrichker

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,048
21,214
234
Box behind Walmart
Sep 9, 2015
#2
  • Sep 9, 2015
  • #2
Nicely done. I can see by your diagram how far up that PCV hose, the oil will want to go. Once it gets to that slow portion, it won't go any higher and will eventually drain back into intake when the motor is shut down.

Not bad at all.

This is essentially what a catch can does except the can retains the oil when the music stops.
 
Reactions: Dyno12

A5literMan

At least it is lumpy...
5 Year Member
Jul 30, 2011
4,674
2,343
194
Illinois
Sep 9, 2015
#3
  • Sep 9, 2015
  • #3
theYman said:
I have researched this topic extensively and have tried multiple fixes. I have used an oil separator, full length intake baffle, larger lines, etc. None of them were 100% successful until now.

I was reading another post from 2006 and the original poster claimed success with this same setup, so I tried it,and it flat out works. I would give him/her credit but I can not find the post now.
It involves using 2 pcv valves ( I used the Lightning pcv) elevated away from the intake. The pcv in the intake is replaced with a 3/4" male to male fitting, then a section of 3/4" heater hose mine is 3", into a 3/4" T, a hose on each side of the T joins 3/4" 90's, then another hose that house the pcv valves on each side. Then the pcv's 90 fitting are connected to each other via a 3/8 T fitting.
Finally, the other leg of the 3/8 T is connected to the line that goes into either your intake vacuum or your oil separator. I kept my separator to monitor if any oil makes it that far, so far none has.
After multiple full throttle blasts I have yet to see any oil in my separator or out the exhaust. Before this mod, my car would smoke after a long idle time and a WOT blast. I have included a diagram that I made to help explain it and picture of my setup .
I have also checked crankcase pressure/vacuum to be sure there are no difference between a single/dual pcv set up. In both situations with my vacuum/pressure gauge attached to my dipstick tube the reading were identical at 2"HG vacuum.
The theory of using 2 pcv's is to decrease the velocity while maintaining the volume of air. Less velocity will carry less oil.
With this mod my car seems to have a deeper exhaust tone, It also does not smoke at all , and the oil separator is bone dry.
Click to expand...
Well done! I'm going to give this a try on my new setup!
 

jrichker

StangNet's favorite TOOL
In Remembrance. Thank you for your contributions
Mar 10, 2000
27,512
2,813
234
Dublin GA
Sep 10, 2015
#4
  • Sep 10, 2015
  • #4
Nice application of some basic physics. This is something to remember when guys with pressurized induction show up with oil in the intake track.
 

89oem

Mustang Master
Dec 18, 2013
1,456
542
144
Sep 10, 2015
#5
  • Sep 10, 2015
  • #5
@RacEoHolic330
 

theYman

Active Member
Jun 5, 2013
88
24
29
Sep 10, 2015
#6
  • Sep 10, 2015
  • #6
The hardest part was finding a coupling that fits into the PCV grommet.
3/4" Barb Coupling
Model Number: 17100625 | Menards® SKU: 6806596
 

theYman

Active Member
Jun 5, 2013
88
24
29
Sep 10, 2015
#7
  • Sep 10, 2015
  • #7
One other thing I would like to add to this post. With the car idling and the dual PCV setup, I attempted to remove the oil fill cap and was surprised at how strong the vacuum is. Almost strong enough not to be able to remove the cap with one hand.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
43,048
21,214
234
Box behind Walmart
Sep 11, 2015
#8
  • Sep 11, 2015
  • #8
theYman said:
One other thing I would like to add to this post. With the car idling and the dual PCV setup, I attempted to remove the oil fill cap and was surprised at how strong the vacuum is. Almost strong enough not to be able to remove the cap with one hand.
Click to expand...


In a closed system at idle, this is what you would expect.
 

theYman

Active Member
Jun 5, 2013
88
24
29
Sep 18, 2015
#9
  • Sep 18, 2015
  • #9
After 300 miles, still not a drop in my separator. For those that are trying this setup please post your results.
 
Reactions: FoxMustangLvr

84Ttop

They make new pistons every day, so why worry?
5 Year Member
Jul 2, 2009
5,222
3,254
204
South Jersey
Sep 21, 2015
#10
  • Sep 21, 2015
  • #10
Noobz347 said:
In a closed system at idle, this is what you would expect.
Click to expand...
This has to be a refreshing win for you @Noobz347 !
 
Reactions: stykthyn
You must log in or register to reply here.

Similar threads

T
Oil burning on my recently buil 302
  • The blk67
  • May 15, 2026
  • Fox 5.0 Mustang Tech
Replies
3
Views
149
Fox 5.0 Mustang Tech May 15, 2026
Noobz347
N
Edelbrock 1405 Setup
  • nathantaylor200
  • Nov 4, 2025
  • Classic Mustang Specific Tech
Replies
3
Views
234
Classic Mustang Specific Tech Nov 5, 2025
nathantaylor200
N
A
Engine Genius installed oil filler above rocker arm…
  • afjLX
  • Mar 27, 2025
  • Fox 5.0 Mustang Tech
Replies
5
Views
507
Fox 5.0 Mustang Tech Mar 29, 2025
nicholase
H
Engine 1987 5.0 HO vacuum hose locations
  • harryhaber
  • Jun 20, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
501
Fox 5.0 Mustang Tech Jun 21, 2025
limp
Engine on3 Conversion to draw through MAF?
  • sav22rem22
  • Oct 11, 2025
  • Fox 5.0 Mustang Tech
Replies
2
Views
264
Fox 5.0 Mustang Tech Oct 11, 2025
sav22rem22
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?