I was confused as to why there were two different types of oil filter scattered across the different engine types for the C2 and C3. And how to tell which one went with which engine, why, and how to figure out which one I would need!
The TU1, TU3 and TU5 engines have the same (confusing) filter and housing arrangement(s). But why?
The "TU" engines have been around for a while now and have gone through a number of modifications. The TU1 and TU3 are virtually identical apart from their displacement. The "block" of the TU1, TU3 and TU5, again, are very similar so to make a modification to all of them at the same time is logical. One of the modifications was to change the oil filter from the "spin on" type of metal oil filter to the "naked" filter that sits in it's own housing. However, it seems that around 2004 PSA (again) made another modification to the oil filter housing and the shape of this naked filter. So if you go back to what was basically the same engine in the old Saxo, there have been; a spin on and 2 types of naked filters used on these engines!!
For us, only the naked filters were used on the C3. The spin-on filters were used on the much earlier cars like the Saxo.
In the C3, the later versions (post 2004) of these housings use a smaller filter than the earlier versions. The earlier versions' filter (pre 2004) also had a plastic 'tail' that extends down into the body of the filter housing. I'll get to what the differences look like in a minute.
There are a number of features on each of the filter housings to distinguish them from each other.
The new housing is over all, squatter than the old version.
The oil pressure switch on the new version sticks out horizontally, the switch on the old version points downward.
The newer oil filter cap has 'ears' on either side.
The newer version has a spring loaded valve in the center of the housing that closes when the filter is removed.
Both of the filters clip into the cap before installing into the housing.
So hopefully that explains which filter you need for your engine...and why!
Picture of the two filters. The OLD type is on the RIGHT. The NEW type is on the LEFT.
The old filter housing and element do not appear to have a bypass mechanism!? If the filter gets clogged, no oil flows! I could be wrong but I cant see any sort of bypass mechanism.
If you note the new filter element, it has a "zig-zag" pattern to the face of the filter paper. The entire filter element would crush down (or up, not sure) under the oil pressure if the element becomes blocked. This allows oil to move around the element seals and supply unfiltered oil to the engine. Very simple but better than nothing.
The two housings.
The caps.
The spring loaded valve in the newer version.
The center of the newer filter has a cross shaped plunger that pushes down on the valve, opening it, when the filter and cap are screwd down.
Oh and by the way the the cap has a fitting on the top to aid removal and installation. That fitting takes a 27mm socket.
And speaking of tightening the cap. The sealing of the cap is accomplished by an o-ring around the side of the cap. This means that the seal is NOT reliant on the cap being tightened down. The cap only needs to be tightened until the cap thread bottoms out. It does not have to be tightened down.
There is a torque specification printed on the cap but as I said, bottomed out and "snug" is good enough.
A new filter should come with new O-rings. One O-ring for the cap (and in the case of the old type filter) an O-ring for the "tail".
