View Full Version : Oil Filter

12-13-09, 03:50 PM
I was reading through the owner's manual for my new 07 and it says the STS-V needs Mobil 1 and a special oil filter, and using the wrong filter could damage the engine and void the warranty. Can someone tell me what this is referring to? Thanks, Craig

12-13-09, 04:29 PM
It's an AC Delco PF26 filter. It has a bypass valve in it. (thanks Florian) :)

12-13-09, 07:47 PM
no worries...


12-13-09, 08:18 PM
Bypass valve??? hmm never heard about that for this car.
I use the Mobil M1-210. Wonder if that has the bypass valve????

12-13-09, 11:54 PM
gotta have the bypass valve or youre in the poo quick.


12-14-09, 06:58 AM
"To prevent a plugged oil filter from starving the engine for lubrication, oil filters can have a built-in safety device called a "bypass valve." When the differential pressure across the oil filter element exceeds a predetermined value (which varies depending on the engine application), the bypass valve opens so oil can continue to flow to the engine. But when the bypass valve is open, no filtration occurs. The bypass valve also opens when a cold engine is first started. Cold oil can be fairly thick and may not pass through the filter element very easily. So the bypass valve opens and allows the oil to go around the filter until the oil warms up and flows more easily."

12-14-09, 12:23 PM
By-pass valve is important. You also need to keep in mind the flow capacity of the oil filter. The engine in my 1991 SHO has a high volume oil pump that flows over 12 gallons of oil per minute. I found out that most filters were only tested to 3 gallons per minute and when the flow exceeds 3-4 gallons per minute most run in by-pass mode. The only filters that could handle the 12 gallons per minute was the OEM motorcraft, Mobil 1 and K&N. I figure this may be case with our engines too and plan on using the OEM filter.


12-14-09, 09:32 PM
No one said if the Mobil 1 has this valve or not???????
I buy the Mobil 1 because i like it and it costs me $5.


Bee iLL
12-15-09, 10:39 AM
Anyone know if the Amsoil EAO11 filter has a bypass valve? Could not find any information on Amsoil's site about a bypass valve...

Edit* Actually found answer to my question. Answer is yes it does in case anyone else was wondering.

Berger 93
12-15-09, 11:47 AM
I use the Mobil 1 with no issue . . . I'd run the AC Delco filter if they hadn't become the holy grail of oil filters . . .

12-15-09, 11:59 AM
THANKS for the replies . I feel better.

12-15-09, 02:41 PM
On start up yesterday the oil temp was 15 degrees and at fast idle the oil pressure was 132 psi .:eek:

After warn up to oil temp of 180 the oil pressure dropped to 41 at idle ,

about 80 psi at 75 mph / 2000 rpm. :thumbsup:

12-15-09, 05:01 PM
I use the Mobil 1 with no issue . . . I'd run the AC Delco filter if they hadn't become the holy grail of oil filters . . .

I bought three of them at one time from a GM internet parts retailer for around 8-9/ea -- no not cheap, but yes for piece of mind.

Useless information of the day, if you look up the PF26 on ACDelco's website we also share this filter with the Dodge Viper..

12-15-09, 09:30 PM
Well crap, I'm shocked. When I take the car to the dealership for an oil change they only charge 6.00 for the PF26. :)

12-15-09, 10:25 PM
What is the difference between the oil filter that fit the 09 motor and an 06?

12-15-09, 11:02 PM
What is the difference between the oil filter that fit the 09 motor and an 06?

Nothing -- The PF 26 has been the filter for all 4.4 LC3 Engines since their induction in the STS-V/XLR-V.

johnny kannapo
12-17-09, 10:59 AM

12-23-09, 08:09 AM
BITOG is the best site for fluid and filtration tech. Most oil filters have bypass valves. Amsoil oil filters are probably the best out there in terms of flow and filtration. KN flows well but does not filter well. If you want the absolute best filter, get a CM Filter. It is a spin on filter with a replaceable cartridge. Very high flow and filtration, but not cheap.