Caution! Losing a part when changing oil filter may mean an engine rebuild!


I have seen too many of these mistakes now that I feel compelled to warn anyone who changes their own Citroen DS or ID oil and filter about it.

There is a part which the oil filter sits on, a kind of stepped washer, which can stick to the oil filter cartridge and be unknowingly discarded with it. When this happens, the new oil filter is not clamped into place properly when assembly is refitted into the oil pump. Although not correct, this in itself will not cause any problem as the oil pump still works and oil pressure can be maintained, it’s just that the oil will bypass the filter and therefore not be filtered before being distributed around the engine.

The problem arises because the oil filter cartridge has a thin gasket glued to either end and when the filter is not clamped into place, the upper gasket is free to come unstuck and work its way into the oil pump. The wayward gasket can severely restrict, and even completely block the oil pump inlet which starves the engine of oil and this eventually results in a nasty rattling sound and an engine rebuild.

I have found a number of filters like this recently, some with 2 or 3 oil filter cartridge gaskets stuck in the pump which indicate it has been that way for that many filter changes. Only luck has prevented these from blocking the oil pump enough to starve the engine of oil, however so far only two have had their luck run out and the engine has been starved of oil enough to wreck the bearings, but not turn the pressure warning light on.

This mistake is usually made by DIYers who did not know the part was missing, or even supposed to be there, and this is understandable, but unfortunately, some of these cars I know to have had relatively recent servicing by other “professionals” who ought to have known better. Hopefully this article will serve to warn others who may otherwise make the same mistake in ignorance. Use the parts book diagram below to check that you have all the parts intact prior to reassembly. Item 23, which the oil filter sits on, is the part which is often lost.

Citroen DS oil pump components

Parts book page for Citroen DS oil pump and oil filter

When changing the engine oil and filter you will need the following parts: Oil filter(item 21), gasket for oil filter cover plate and a new drain plug washer. Parts you may also need are the large O ring (item 35) and small O ring (item 34), depending on the condition of yours. These O rings often go hard with age and break, so if you need all parts, they are also sold as a kit.


4 Comments on “Caution! Losing a part when changing oil filter may mean an engine rebuild!”

  1. Trevor BERGMAN - Victoria Australia says:

    Would not having the large O-ring on the filter lead to the upper gasket on the oil filter coming off and blocking the oil pump?

    • As long as the filter element is clamped between the spring loaded stepped washer and the pump body, the gasket cannot escape. Having either of the the O rings missing would not allow the gaskets to escape, only the filter to not work as intended.

      • Trevor BERGMAN - Victoria Australia says:

        Thanks for getting back to me. The reason I asked was because my dad rebuilt my DS23 motor and it developed a bad oil leak almost straight away and blew smoke. When we pulled the motor out the top gasket was blocking the oil pump, but he had the stepped washer in. He has rebuilt engines for decades and never had this problem. Could the spring in the stepped washer possibly lost tension and enabled top washer to come off. I don’t know if you have ever heard of that happening before. Just trying to make sure it doesn’t happen again.

      • Citroen Classics says:

        I guess that if the spring broke or lost tension it would not hold the filter tightly enough, which would cause that. I’ve only ever seen it happen when the stepped washer is missing, but anything that causes the filter to not be clamped properly, even the alignment of the bottom cup (triangle markings not adjacent to each other) would do it. Darrin


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