one other oil to use is mobil one 15-50. it also has seal conditioners and is a high quality oil that would be great for a low milage car like yours. as to seal conditioner in a can for 3.00, these are too strong for low mile cars.
seal conditioners soften rubber seals that are dried out.
works great on much older cars on there last leg.
some of those seals that are in great shape on your car will be made softer, but if you need it again for those seals,they may be over cooked,then you have a real leak that could have been fixed with one can.
mobil one is worth a try, plus you get extended oil change intervals,better engine life,maybe better milage
seal conditioners in high mile oil or mobil 1 are gentel but do the job imho mobil first then hi mile
just a thought good luck
rich

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88 300E White, sold 9-04
88 190E Black 2.3 sold
90 300CE White, Grey sold 12-24-04
92 400E White,Grey Sold 5-06
90 300CE 91K Signal Red,Black Sold 2007
1989 300CE Smoke silver,Tan Sold 1-08
1993 300E 3.2 M104 motor
1991 300CE White,Grey
1994 E420 beautiful car,gone to new home
1994 E320 Smoke an Parchment.Beautiful car