is it safe to start running synthetic oil with 135k? i bought my 94 gt about a year ago with 130k on it and would like to use synthetic oil if its safe but ive read that it could cause leaks etc.. is this true?

 

heard that too. Maybe try a thicker weight like a 20w50 or straight 50w.

 

I switched it into a car with 170k... it did cause the valve cover and cam seal to leak. I replaced both and ran the car for 5 years without adding more than a 1/2 quart between oil changes. Your results may vary lol

 

well as of right now it doesnt leak burn or smoke any oil so i think ill just be safe and not go to synthetic. thanks for the help

 

personally, I am not going to run any oil in my car for 10,000 miles like they claim can be done. maybe 3k or 2k with just regular Halvoline.

 

it shouldnt be a problem actually. Old synthetic oil used to penetrate the seals and cause leaks but current synthetic oil doesn't do that anymore. It's safe for all vehicles.

 

Just use the synthetic if you're thinking about switching. When i bought my car i switched to mobil 1 10w-30 and never looked back. It leaked just a little bit with regular oil, and switching to synthetic didn't make it any worse.

 

20-50? Must be worn out to use that. Put it in a bb Merlin with 900hp. No street car deserves that heavy of oil.