Replacing Discontinued Mahle Hydraulic Filters

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A customer needs to order Mahle filter element part number OC 176. This is a low pressure spin-on filter cartridge with microglass media. Mahle OC 176 is listed in the catalog but has been discontinued since November of 2012. Specialized equipment uses high quality Mahle filters.How is the problem to be solved?

Specifications for Mahle OC 176 are needed. Consider flow rate and working pressure for the filter element. Flow rate is 25 liters per minute lpm) or approximately 6.6 gallons per minute (gpm). Working pressure is listed at 10/16/25 bar or 140/230/360 psi. The next specifications to consider are micron rating, media type, and connection size.

Micron rating is the contaminant particle size the filter media will capture. The OC 176 is rated at 25 micron. The filter media is synthetic media also known as microglass compared to paper media. Microglass media in general performs much better than paper media for hydraulic filters. The filter surface area is for OC 176 is 1200 cm2. Mahle publishes filter surface area in their catalogs and this is a measure of quality.

The OC 176 element has a connection size of 3/4-16 UNF 2B. The replacement alternative should match this specification or the filter head will need to be replaced.


Mahle manufactures OC 168 hydraulic filter element. It matches the OC 176 except for the following. The OC 168 has a 10 micron rating which is finer than the 25 micron rating of OC 176. The OC 168 has a slightly larger filter surface area of 1309 cm2 versus 1200 cm2 for the OC 176. The OC 168 is available! The filters also match dimensionally. The filters will install on the existing filter head with the same space requirements.

The good news is the OC 168 is a finer micron filter element with slightly greater filter surface area. The finer filter will capture and hold more contaminants than the OC 176. Depending on the level of contamination within the system the finer filter may have a shorter life cycle compared to the coarser original OC 176.

Sometimes the solution is not so simple. What if the OC 168 were not available? The most efficient way to solve the problem would be to match the previous specifications as close as possible and the change the filter head with the required connection size and operating specifications and physical dimensions.

Source by Mark Leach

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