I have put full syn in my 93 se-r with 115,000 and in my sohc 240 with 127,000 i have had no problems and no leaks. I use to have an old 89 volvo 240 i used 10-30 syn until the tranny went with 275,000 maybe on abused cars you might have oil leaks but not well taken car of cars. i would try the blend and see how that went, then go syn.am3rican said:the last thing you want to do is put synthetic in your car. please please follow my advice and just use regular oil. synthetic oil is for new cars or cars with very low mileage. ive had plenty of friends put synthetic in their high mileage cars, and it bleeds right through, sometimes taking the head gasket with it. you might be able to get away with a sythetic/regular oil blend.