Hi everybody.

For my S5-Turbo rebuild I thought I go with the N390-10-502 metal gasket for the front cover. But from all the posts in the forum it was unclear if either the O-ring or teflon ring should be used with it or not, so I went without any like it is done on a Rx8. But a Rx8 has the O-ring land flat on the front iron and a S5 doesn't...
Since I still see fluctuating low/high oil pressure readings at constant RPMs and the pressure seems to get worse lately my question is, if using the metal cover without an O-ring or the teflon ring was the right way to do it or if another component could be the cause for my fluctuating and low oil pressure?

kind regards,
Harry

 

i've never been one to think leaving the o-ring out altogether was a good thing, but i understand that others might do things differently.

here's a good guide to how you might need to approach your front cover and o-ring situations: https://mazdatrix.com/86-92-front-cover-o-ring/

 

i feel bad because its a lot of work to pull it apart, but....

depending on which front iron you have, i think you want to run the O Ring and maybe the support piece too. i think every time i've used a metal gasket i've either cut the o ring section off, and used the stock O Ring and Keeper, or just the O ring (its been a while)

 

If you do remove the front cover while the engine is in the car, you NEED to familiarize yourself with how to prevent the thrust washers/bearings/whatever from falling out of place in case you aren’t familiar.

I suggest running a proper electric aftermarket oil pressure gauge off of the oil filter pedestal to get an accurate reading if you haven’t already.

 

Seems to have been a dying oil pressure sending unit in the end. With another one I have consistent readings for now. Hope it stay's that way

 

^ that’s why I mentioned it’s good to run aftermarket gauges. At least all the components will be new, and you can have 2 sources of “truth” to cross check against.