Oil Filters

The Volvo (reputedly a Mann 917/1) preferred for its better anti-drainback performance, and the correct Champion. External height of the Volvo 3.25", the Champion is 4". The sealing ring of the Volvo looks to be a little smaller, but they measured at 2.79" dia (Volvo) and 2.81" (Champion) so hopefully insignificant. A subsequently purchased Mann 916/1 measures about 3.75" (95mm) external height i.e. close to the Champion.

Cellophane covering for the (boxed) Champion, don't recall this before 2010. The Volvo filters aren't boxed but come with a flimsy plastic end cover pushed into the threaded hole.

Three frames from the YouTube video measuring the depth of filter 1, which gave zero oil pressure ...

... comparing the depth of filter 1 to the anti drain-back tube - little if any clearance ...

... and Comparing the depth of filter 2 to the anti drain-back tube - maybe a couple of inches of clearance

Of course the same thing could have been done by putting each filter beside the anti drain-back tube, probably to greater effect and in a much shorter video, but some people just love making things more complicated than they need to be. And it would have been much more helpful to tell us how high the bad filter and the tube were! My tube is 2" long measured from the filter seal ring, fits inside the bypass valve spring inside the filter, and the internal depth of this Mann 916/1 to the face of the rubber seal is 2.956"

Some filters have a single-piece pressed end-plate with just a moulding to centralise the filtration cartridge, like these stills from a video of a Fram PH2800 series - GFE121F remember - that showed the collapsed filtration cartridge, i.e. it had no (effective) bypass valve. This is just a simple pressed steel spring to block off one end of the filtration cartridge and to press the other onto the end-plate so all oil has to flow through the filter. This is not a bypass valve, and maybe coincidentally the video shows how the filter cartridge has collapsed, quite possibly from excessive pressure. Some filters with this type of end spring do apparently have a bypass valve as part of the anti-drain valve i.e. near the open end, but they are much harder to identify unless you cut the filter open.

This Fram PH8 does have a plastic bypass valve in the end spring ...

... but it also has a damn great hole in the filtration cartridge where the ends of the filter strips haven't been crimped together correctly! And cardboard end-plates just glued on.

Inverted spin-on filters need an anti-drainback valve internally to prevent the filter draining when the engine is switched off, which delays oil reaching the bearings on start-up. Hanging filters don't need it, but I'd expect all good spin-ons to have one. Having said that not all do, and some valves and elements are very poor quality, as can be seen above. The valve can be seen through the inlet holes on this Mann 916/1 filter:

Anti-drainback valve is the white rubber cupped disc which stops oil falling back through the inlet holes and draining the filter. The anti-drainback tube that is part of the filter head and goes up through the filter outlet reduces how much the filter can drain in that direction.

Element is 57mm long, with metal end-plates

Pressure relief valve. Internal dimensions from the face of the rubber seal are 2.12" to the end of the spring and 2.96" down the centre of the spring, which is approximately .585" internal diameter, i.e. more than wide enough for the filter head anti-drainback tube to fit inside, which in any case is only 2" long.

Oddly the central tube through which the filtered oil passes to leave the filter only has two rows of holes right at the far end. This means oil passing through the rest of the element has to pass down the pleats to leave the filter, with a greater volume needing to pass the nearer it gets to the holes. The elongated 'bumps' closer to the other end will hold the pleats away from the tube allowing more 'flow space'.

Pressed-steel spring to push the element and the anti-drainback valve against the mounting plate, to prevent oil bypassing the element altogether.

Volvo 3517857-3 reputedly made by Mann does look identical externally ...

... and has the same cupped disc.

Filtration element about 50mm long, metal end-caps

Perforations all the way up the central tube with what looks to be the same bypass valve spring at the bottom. 1.77" to the end of the spring and 2.57" down the centre of the spring, which is approximately .585" internal diameter, i.e. more than wide enough for the tube to fit inside.

Bypass valve, oil comes in the outside of the filtration element so excess pressure will press down on the black disc to open the valve and release the pressure into the space that leads to the engine, instead of bursting the element.

Same pressed-steel spring in the base of the can.

Champion C102 - no anti-drainback valve, just the element pressed against the mounting plate

Element about 67mm long, metal end-caps

Perforations all the way up, in a strip wound in a spiral to form the internal tube

The by-pass valve of the Champion is 2.785" to the centre of the valve, 3.495" to the side of the valve.

Bypass valve

Coil spring to press the element against the mounting plate.

The Unipart GFE 422 interestingly has a similar former to the Mann i.e. just two rows of holes at the closed end albeit with a smaller number of larger holes. It does not have the visible by-pass valve spring of the Volvo and Mann, but what could be it's equivalent. External length of this filter is 3.5", internal depth to the centre of the bypass valve is 3.07", internal depth to the side of the bypass valve is 3.31", which gives a much smaller overall distance for the valve (less than half an inch compared to more than an inch and a half for the Mann).


Halfords HOF319 for the ZS180. With anti-drainback valve although one is not needed with the hanging installation.

Element 87mm long with metal end-caps

Similar anti-drainback valve spring ...

... and valve

Pressed-steel spring at the base

MGR LPW100161 for the ZS180. No anti-drainback valve, although none is needed as this filer is hanging.

However the bypass valve is mounted at this end of the filter

Element 77mm long i.e. shorter than the Halfords

Plain end at the bottom of the element

Perforations all the way up

Coil spring at the bottom to press the element, bypass valve and end-cap together.