Sponsored

What could this be?!

shadows_5.0

Member
Joined
Jan 3, 2025
Threads
7
Messages
11
Reaction score
1
Location
los angeles
First Name
shadow
Vehicle(s)
2019 Mustang 5.0 California special
So I popped the hood today and I noticed my breather filter on the catch can is bubbling? I scanned the car to make sure there wasnt anything going on code wise.

what do you guys recommend I check or do?

what is causing this and what could it be affecting in a negative way

Sponsored

 

Skye

Well-Known Member
Joined
Jan 18, 2022
Threads
13
Messages
2,944
Reaction score
4,123
Location
≈39N
Vehicle(s)
"Skye" Mach1 N2144
By viewing the video full-screen, I could see the bubbles.

When is the last time the catch can was emptied?

If you open the catch can, what does it look like inside?

How often is the catch can emptied?

When the catch can is emptied, how much oil is in it? The rate of fill?

The breather filter, can that be removed and cleaned? It is serviceable?

What is the oil consumption of the engine?

Is there any coolant loss involved?

Is the engine otherwise operating OK?

Edit,

If you've not done thus far, the can needs to be emptied consistently. How often is up to each engine. You can start by checking monthly, to determine the rate of capture. In my example using a stock engine, I can empty at each oil change.

If you find the can is filling up more often than expected, that could be several things. At one extreme, internal engine problems and a lot of oil blow-by or crankcase pressure. At the other, a PCV valve that is stuck open at idle, drawing oil due to high vacuum.
 
Last edited:

CrazyHippie

Well-Known Member
Joined
Jan 27, 2023
Threads
11
Messages
880
Reaction score
1,096
Location
Michigan
First Name
Craig
Vehicle(s)
2023 Mustang GT/CS
I'd take it apart and clean it really well, including the filter mesh and screen, with a good degreaser.
 

OldbutNew

Well-Known Member
Joined
Jul 22, 2024
Threads
6
Messages
237
Reaction score
267
Location
S.E.Michigan
First Name
Greg
Vehicle(s)
2019 Kona Blue GT 10R (Wife's car) 2018 Mustang GT Royal Crimson PP1 Manual
PCV systems on boosted engines are touchy at best.
When a naturally aspirated engine is at idle and part throttle, there is vacuum that pulls the vapors out of the crankcase, through a series of baffles designed to remove the larger oil droplets, and through the intake. When you go larger throttle openings, the vacuum drops and the system gets a chance to "relax" . All the oil contained in the cam cover baffles (On a Coyote that's a LOT!) can drain and make room for more oil. On a boosted engine your larger throttle openings see positive pressure. On some applications, your intake is seeing low boost even at steady-state cruise when the PCV system is looking for vacuum. S550 GT500 has the self-draining catch can due to the combination of these factors.
All the above comments and suggestions will help. Monitor that can constantly. Like every time you drive the car until you have it characterized and documented. Then keep it emptied and cleaned.
 
Last edited:

HKusp

Well-Known Member
Joined
Jul 22, 2021
Threads
37
Messages
2,232
Reaction score
2,876
Location
Hampton, Md.
First Name
Jason
Vehicle(s)
2018 Mustang GT
So I popped the hood today and I noticed my breather filter on the catch can is bubbling? I scanned the car to make sure there wasnt anything going on code wise.

what do you guys recommend I check or do?

what is causing this and what could it be affecting in a negative way

You just bought this car, correct?
Sponsored

 
 








Top