2013 Taurus with 33,000 miles. I have been using the Ford branded synthetic blend oil since purchased. I’d like to switch over to full synthetic oil. I’ve had some unfortunate issues using full synthetic on other make cars in the past. These cars had low mileage and each was relatively new at the oil change. Both vehicles developed leaks within days of the change and both occurred at the valve covers. So, my experience with synthetic has not been good. My question is has anyone here switched over to full synthetic after a significant amount of miles? Any issues? I understand tolerances today are much different than they where years ago and this shouldn’t be a consideration. Opinions? Thanks in advance!
Changing to synthetic oil.
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It won't hurt anything. Modern cars are typically sealed much better than the olden days, and assuming you've kept up on oil change interval it's very unlikely you'd notice any problems. Even if you do get a leak around the VVT solenoids, that was going to happen anyway, lol.
What do you hope to accomplish by switching? Yes, synthetic will probably leak (at least for a while, until the seals become conditioned to it), so just plan on it.
Or DON'T switch. Full-synthetic oil contains exactly 0 synthesized molecules (same as semi & dino), and does NOTHING that semi-syn and good plain oil don't do.
Or DON'T switch. Full-synthetic oil contains exactly 0 synthesized molecules (same as semi & dino), and does NOTHING that semi-syn and good plain oil don't do.
My 2004 ran on Motorcraft semi syn until 2012 and about 60k miles. Went to full synthetic. Leaks started about 4 years / 25k miles later.
The saying here about Duratecs (of my era) is that if there isn't oil under them, there is no oil in them. In other words, the leaks are inevitable. I don't think full synthetic oil caused leaks in my case.
Two things I may have done differently though are:
1) Not to have gone with as significantly longer oil changes as I did. All oils contain seal conditioners so running oil longer may mean less conditioning (since all additives get depleted).
2) Used a high mileage oil (which I still haven't done). They have more seal conditioners. Instead, I just got full synthetic on sale, sometimes for free after rebate.
Oddly enough, I used semi synthetic once more after switching to full synthetic and that was the first time I got leaks. I distinctly remember that oil being very black and appearing quite worn when I changed it at 5000 miles and the engine not feeling as good with semi synthetic as it did with full synthetic even when run to 8000 miles.
The two oils that seemed to do best in the Duratec (from the point of view of hardly any drop in level, less leaks and engine feel) were Valvoline full synthetic and Shell Gas Truck, both 5w30. If I were to buy an oil at full price for the next oil change, I would probably go with Valvoline high mileage full synthetic.
I used Motorcraft oil on my 2008 until 100K and then switched to Valvoline full synthetic till 302K when I got rid of it. Not a problem at all. I had also switched 2 other cars that I still have with simular milage (Different makes) and had no issues. I wouldn't worry about it to be honest.
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I purchased my 96 with 39K and immediately started using Mobil 1. I now has 289K Still does not burn any oil. You will be OK. I since changed over to the Extended Performance Mobil 1 but you MUST use the Long mileage oil filter with the change. Then I only run it to 15K rather than the Mobil stated 20K miles. Still the best on the Planet.
Do you have any used oil analysis from the 15k mile oil? Presumably you do mostly highway driving and change approximately yearly?
Full synthetic is the best you can use. It clings to parts better reducing wear on startup, it breaks down slower, it can withstand heat and cold better, its better in almost every aspect besides price. The main reason it would cause leaks is because the leak was already there and using the full synthetic can clean the gunk out and also flows better, which would find its way out.
I sent some full synthetic oil in after 5,000 miles and it came back as good oil, the lab said could probly get another 2,500 miles on it no problem before needing a change. However I still change it at 5k knowing there is still great protection happening.
I sent some full synthetic oil in after 5,000 miles and it came back as good oil, the lab said could probly get another 2,500 miles on it no problem before needing a change. However I still change it at 5k knowing there is still great protection happening.
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