Oem or aftermarket oil filter?
From jan@lipari.usc.edu Thu May 18 17:15:09 EDT 1995
I dissected a VW and a Fram oil filter a little while back.
These are the differences:
- VW filters (made by MANN) had a more rigid casing. There were also more
welds to hold the casing and the top together. This is important
as oil pressure may blow the oilfilter appart. (Uncommon, but known
to happen [Recently several cases were reported on Corrados G60s &
Porsche 944s where the FRAM filters ruptured or the seal gave way,
destroying the engines.
Factory warrantee was voided, the person in the 944 however won a
case against FRAM].
- VW had two spring loaded valves (anti backflow & bypass)
while FRAM had one spring loaded and one rubber membrane type valve.
The anti-backflow valve will prevent retain most/some of the oil
from draining out of the engine, thereby supplying the engine with
hard needed oil immediatly at start up.
Presumably, the springloaded anti-backflow
valve will do the job better then the rubber membrane. The bypass
valve alows oil to bypass the filter when the filter is either
clogged or too viscous. I read somewhere else that the FRAM's
bypass valves are sometimes set too low such that no filtering ever happens.
- The parts to which the ends of the filter element was attached
were metal in the VW filter and cardboard in the FRAM filter.
- The pleats of the filter element were neat and regular in the VW,
croocked and held together with a little string in the FRAM.
- How the actual filtering compares, I don't know. According
to Consumer Reports, they are similar (but the rest ISN'T).
Other case in point:
A friend with a Mazda truck experienced rod nock with FRAM
filters at start up. Upon consultation with Mazda, he switched back
to Mazda filters, which solved the problem. Presumable the afforementioned
valves are to be blamed.
In article db36+@andrew.cmu.edu (David Stuart Bridge) writes:
I recently heard some talk at my mechanic's garage about using only Mitsubishi
oil filters on Mitsubishi engines. Apparently, use of non-Mitsubishi filters
can cause some real problems -- some guys said they came accross engines that
were blown because of the "wrong" filters.
In general, I found the FRAM filter of significantly inferior construction
compared to the filter I normally use [on VWs]. The above was enough evidence
for me not use Fram filters (or most other brands) for my car.
It's worth the small $ difference to me. (I buy my VW filters on the rare
sales some of the dealers have, in which case the filter cost me about
US$5 (vs $4 for FRAM).
I used to be able to get MANN for about that much as well through
Beck Arnley, but since they merged with World Parts I have had trouble
finding them [and haven't really tried either]).
Your [non-VW] car might be perfectly fine with Fram filters if the
original equipment and the Frams are similar in construction.
Your OEM filter may not require these valves.
If you want to be sure, get a hacksaw and see for yourselves.
[It's a big mess if you use used filters though. Let them first "drain"
overnight].
Jan.