My son put his new fuel filter in backwards can I just turn it around or is it ruined now?
Just turn it around
The only difference between frontwards and backwards is that the filter has a tendency to flow less fuel when installed backwards. On some cars this can show up as a stumble or cutting out on acceleration.
The filter is not ruined.
If it has beennrun that way for any length of time, I wouldn’t try to reverse & re-use the filter myself. Any dirt in the fuel has been trapped on the fuel tank side of the filter. If you now reverse the filter, that dirt will flow right into the injectors. Replace the filter with a new one.
It’s surprising to me it can be installed backward. On all the fuel injected car’s that I’ve replaced fuel filters, the in and out connectors have different configurations. Suggest to make sure it is actually installed backwards in the first place.