Hello
just bought a 2013 ford fiesta titanium with less than 40k miles and have a few maintenance questions:
1) which engine oil should be used? Can I use mobil1 5w20 full synthetic instead of the other brand that’s recommended in the manual?
2) same question for engine oil filter. Can it be a different brand like mobil1?
3)if full synthetic is used, how often should oil be changed? And what if synthetic blend is used?
4) is there a part number for the drain plug washer? If you have a link to it, that’d be great
4) any recommendations for engine air filter brands
5) is there anything else you’d recommend replacing besides the above?
A lot of these questions come up on a regular basis due to the problems encountered in the past, so to ask them is valid - but only to a degree of - if you pay attention to the details - it won't be a problem because they fixed "this" a while ago.
Firstly - congratulations on buying a Ford Fiesta - we wish you a lot of happy miles with it.
IF you can research what the former owner used, and even did with the car - it may help you understand how to preserve the vehicle in it's current condition for a longer time.
While you're at it, find the owners manual - it may have receipts as well as some written data from the previous owner on what was done when they first got it - then you can develop a plan of action using that to help keep your car on the road longer.
Some owners store theirs in a garage, others in a storage unit while others use theirs everyday but wash it on a regular basis but only as a means to keep the birds, dirt and tree sap off of it. So it might help to research the way it was and why it was kept in that way.
So if you look under the oil cap - review the condition of the sludge or residue under the cap - that is what remains thru-out the motor in some form or another so if you wish to change brands of oil - it might not change or get rid of the residue - so don't expect miracles switching to a different oil brand as either being damaging (unlikely) or working better (again- unlikely). If the former owner did their job right - this whole thing becomes moot, for the oils and fluids and care from the owner - all worked together and did their jobs so you don't have to make drastic changes in design or maintenance schedules - you pick what you want to use and stick with it - it then becomes your responsibility.
It really all depends on how well you stick with the maintenance and the proper weights (Viscosity) and fluid levels and their types - changing one type - like the Coolant - can damage the vehicle permanently and make it becomes a costly mistake.
It's more than likely a car with such low miles after all these years doesn't mean it wasn't used - I hope not, for engines that sat for long times without running are worse off even using the synthetics to preserve them because the oil drained out of the spots it's designed to coat, with itself. It may coat and stay on for a long time but doesn't mean forever - so the seals and materials the engine uses to keep fluids where they belong - can be slowly digested or dried out - creating another more serious problem later.
Remember the Fiesta was made from the foundations of the other models the brand developed - so they are not going to produce something that makes the whole brand look bad and sour like lemons. So the effort to switch to something new might not give you the results you'd expect - because the formulations and bases of the materials the new stuff is, has not changed all that much nor is the additives used that are designed to be too aggressive and remove the old oil for it can remove the coatings that oil provided as well as damage the engines own preservatives like what was used in the seals - so the automakers and the oil makers are working with each other to help reduce the chances of you getting a bad apple from the bunches of products they produce to help keep your car like new. Both their reputations are on the line when it comes to proving their claims.
I myself have stuck with Motorcraft due to the Filter sizes and fitment - just remove the old and reinstall the new one - no hassles. You don't attain much benefit from trying exotic methods and installing contraptions that have not been recommended by the maker - they can damage parts further down the line - and possibly violate any possible warranty on the other products installed from previous maintenance and repairs.
). I regularly drove the car spirited and occasionally went to the drag strip. The car still ran when I sold it and the new owner drove it away. I think it became a derby car 
