Will Synthetic Motor Oil Cause Engine Seal Leaks? Let's find out!

  • Published: 07 October 2019
  • Conventional Shell Rotella T4 15W-40 compared to Full Synthetic T6 5W-40 for causing engine seal leaks in a 45 year-old Ford 5000 tractor. I bought the oil used in this video and do not have any sponsors. Thank you very much for supporting the channel by watching the commercials and through Patreon support. https://www.patreon.com/projectfarm

    Merch: https://teespring.com/nl/stores/project-farm

    This video is only for entertainment purposes. If you rely on the information portrayed in this video, you assume the responsibility for the results. Project Farm LLC
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Comments • 9 424

  • Jim Allen
    Jim Allen  2 hours back

    I switched over a 1991 Lexus LS400 with 85k miles to full synthetic Mobil 1 and the rear main engine seal started leaking. I then switched to full synthetic Valvoline and the rear main seal leak went away. Stuck with the Valvoline after that and never had a problem since.

  • MotoMark
    MotoMark  9 hours back

    I put synthetic oil in everything I own new or old never had it cause leaks

  • Lyon Thomas
    Lyon Thomas  13 hours back

    Why is my hay fever kicking in?

  • Adam T
    Adam T  20 hours back

    video was awesome.
    and on a side note, i have used T6 in my 2010 kawasaki zx14 since it was new. it has the jaso approval that my wet clutches use. i haven’t had any issues with using it.

  • Lost Ship
    Lost Ship  20 hours back

    Where does he send the oil for testing in his videos?

  • C White
    C White  21 hours back

    That compression restore will falsify your oil analysis results.

  • Ryan Atwater
    Ryan Atwater  22 hours back

    I have a 2003 toyota sequoia. It has 310,000 miles. I have ran conventional oil in it its whole life. I switched to synthetic about 3 months ago. I now have valve cover gaskets leaking. From my experience in the field synthetic oil does not have the swelling properties on rubber that conventional oil has. Either way it's going to get valve cover gaskets. Love your channel. Thank you!

    • Project Farm
      Project Farm   11 hours back

      Great feedback on the valve cover leaks. Did you use a "high mileage" synthetic? They have the seal conditioners that help.

  • 2112 Bangkok
    2112 Bangkok  23 hours back

    Wheelie alert at 9:12

  • matthew stover
    matthew stover  23 hours back

    How about going back to regular oil. Will it leak then?

  • Brian J
    Brian J  24 hours back

    As a Shadetree kid growing up, this channel deserves serious recognition.

    Keep up the expert work!

  • Michael Szczys
    Michael Szczys  24 hours back

    Most synthetic oils I have seen are very thin weight. If it leaks with 30 wt. it most surely will leak like a sieve with 5wt. synthetic

  • Rich s
    Rich s  1 days back

    I own 9 superdutys, all with the 7.3 powerstroke, Mileages from 120,000 to 500,000 I do ALL my own mantainace and repairs, keeping all of them in good shape, I started a program switching to synthetic oil, I got 3 of them done, ALL 3 trucks started leaking oil, they leaked oil from orifices that I didn't know existed, ( OK, A BIT OF exaggeration) but you catch my drift) I stopped the program of switching and went back to regular oil, low and behold I stopped buying oil floor dry. NEVER AGAIN.

    • DJ cars ER DJ cars ER
      DJ cars ER DJ cars ER  1 days back

      When you opened that oil filter I saw a large chunk of metal, thought "Oh Man your tractor is toast!" Turned out to be a chunk of dust on my laptop screen. Please keep these great videos coming!

    • awesome honda
      awesome honda  1 days back

      Where I work we use T6 5w-40 in everything. Cummins, powerstroke, duramax, Detroit diesel, anything. Trucks from early 2000s and newer. Some with over 300k miles and I’ve never seen a leak on any of them that was caused by changing your oil to synthetic.

    • Steve Friend
      Steve Friend  1 days back

      Very good job on the analysis. I have run Mobil one in my gas motorhome and various cars. No leak issues. I have run Rotella T4 in my 2004 Cummins and my 2005 Cat Diesel in my Motorhome. No leaks. Actually got about a 1 mpg increase in the MH and about the same in the Cummins.

    • Douglas Lynch
      Douglas Lynch  1 days back

      My dad switched to full synthetic years ago on our family 1976 Ford van. It had the 300 ci straight 6. It did indeed start leaking oil. I believe he changed out the old cork gaskets...

    • Nick Collins
      Nick Collins  1 days back

      Synthetic engine oils can cause leaks where rubber gaskets are used, it has to be used for extended time to occur. Natural petroleum products swell rubber over time causing seal break down and leaks, synthetic products contract rubber seals over time causing them to leak. Both over time can cause leaks but on older model engines with looser clearances on sealing areas conventional oils do better, causing less leaks in general because of swelling effects of natural petroleum on rubber, allowing it to seal larger areas better, synthetic is more likely to cause leaks sooner on these older designed engines. On modern engines it's really not an issue due to such tight seal clearance designs.

    • First name Lastname
      First name Lastname  2 days back

      Huge protocol error. Never test two things at the same time. Unless your are testing interractions. You put an additive for old engines into the oil. The remainder of the test is moot

    • Charles Kelbley
      Charles Kelbley  2 days back

      I have had others complain to me about their engine leaking oil after switching to synthetic from conventional. Come to find out, they had been using high mileage conventional oil, then switched to full synthetic without using the high mileage full synthetic oil. For years I've noticed that engines always leak more oil after replacing high mileage oil with regular oil, regardless of the oil being conventional, synthetic, or a blend. Perhaps your viewers who encouraged this video had been in a similar situation.

    • Thought Challenger
      Thought Challenger  2 days back

      Brake fluid revives rubber.
      How much brake fluid mixed with oil causes damage?

    • Lagoon Platoon
      Lagoon Platoon  2 days back

      I used synthetic in every car I’ve ever had never caused a leak. I use royal purple with a zinc additive in my 76 Lincoln. Never leaked a drop

    • Lee Smith
      Lee Smith  2 days back

      I saw you add engine restore and am wondering if I should start adding it to my 1974 case 580b. She works good but always needs quick start to first get going smokes a little until warm but runs fine. I currently and for the last 5 years have used motor master 10w30 semi synthetic diesel oil in her.

      • Lee Smith
        Lee Smith  2 days back

        Project Farm thanks for the reply I am looking at Canadian Tire website and realize they sell 325ml for 4 cylinder, 443ml for 6 cylinders and 561ml for 8 cylinders. Mine has 4 and wondering which one to buy and how much you put in yours. Mine takes 5 litres of oil
        Thanks again

      • Project Farm
        Project Farm   2 days back

        It shouldn't hurt anything to try it to see if it helps. The Ford 5000 is definitely running much better than before

    • MR. FUSON
      MR. FUSON  2 days back

      I had a 1997 Toyota Tercel always used conventional motor oil and the car ran great and never gave me any issues. When synthetic oil came out I thought it would do it a favor and put the high-dollar synthetic Mobil 1 in it. After a couple weeks and driving it it begin to smoke and Shake. I checked the dipstick and there was virtually no oil in the motor!!! A mechanic friend of mine told me never put synthetic oil in a old engine that had never used it because it was thinner and it would seep out of the gaskets. But if it had been a new motor it would not have done that. I don't know I'm not a mechanic but that was my actual experience

      • Project Farm
        Project Farm   2 days back

        Thank you for the feedback on synthetic in the Toyota

    • Na Rong
      Na Rong  2 days back

      Makes farm work look fun! Loving this channel

    • Liam Duval
      Liam Duval  2 days back

      Great channel man

    • Kirk Larson
      Kirk Larson  3 days back

      I had to watch this. I have a 2000 Jeep wrangler with over 100K on it. It's my wife's daily driver and she's a stickler about her vehicles. The jeep didn't leak at all. Several weeks ago, the parts store has a deal on a filter/oil combo and it was with synthetic. Never used synthetic before but thought I'd give it a shot. A couple days after the change, I get the "Sweets, there's oil drips under the jeep in the garage" I check and sure enough there's a few dribbles. Me, knowing the story about synthetic causing leaks, didn't say a word. I have the ability but not the desire to reseal a 4.0 because of some dribbles. It's been a few weeks now and I haven't heard anymore comments from my lady so either the dribbles were remnants from the oil change or it sealed back up. Either way, I'm not looking under the jeep.

    • Funkmaster Blaster
      Funkmaster Blaster  3 days back

      That's a rugged little tractor..

      • Project Farm
        Project Farm   2 days back

        It's amazing the tractor is 45 years old

    • VNTIL8TR
      VNTIL8TR  3 days back

      Some of the most thorough tests conducted on YouTube! Kinda hard to find anything you missed that I wouldn’t!

    • Derek Natan
      Derek Natan  3 days back

      Never noticed any leaks in my 2006 Nissan Sentra 1.8. Great video!

    • Mike Schneider
      Mike Schneider  3 days back

      I'm guessing that a low-revving tractor is not the ideal test for this sort of thing, whereas maybe old motorcycles would be.

    • What Ever
      What Ever  4 days back

      Every car that I have used synthetic oil have ALL leaked oil from the seals. The only cause I can think of is that they have all been under the year 2000. Maybe the seals in newer cars are made to work with synthetic oil.

    • 20 below
      20 below  4 days back

      I've been buying 80/90s Toyotas my whole life. I put Mobil 1 in ever single one and it never caused any leaks. Thanks for the video. Now I'm considering putting T6 in my Kubota because it's often -20F here.

    • Mowers N Blowers
      Mowers N Blowers  4 days back

      Wow, same tshirt

      • Eric Santiago
        Eric Santiago  4 days back

        I’ve never had an issue but when I changed over to synthetic is my always conventional ran
        1997 Jeep Wrangler 2.5L 223K
        1992 Nissan stands 2.4L 160k
        And my 2002 Silverado 6.0, 240K
        I developed a lifter tic upon startup on all 3. But after about an oil change or 2, the tics always went away. And the engines always seemed quieter than they did before the tic. My guess is the synthetic would loosin up gunk and cause clogged ports but after continual use got rid of a lot of the buildup

      • Enrique Rodriguez
        Enrique Rodriguez  4 days back

        U should test if synthetic burns faster than conventional motor oil?

      • Tony
        Tony  4 days back

        I bought a foxbody that ran on regular oil it's whole life with 150k miles. It never left a drop on the driveway. After using synthetic and driving 40 miles a day for 4 months my results were a leaking rear main and valve cover gaskets.

      • infinity
        infinity  4 days back

        one had more oil in it

      • Gregory Masincup
        Gregory Masincup  4 days back

        Synthetic oil does cause leaks and damage to engine when regular oil is used and switch to synthetic and switched back to regular. Remember synthetic rule once use synthetic oil you can't go back to regular ase certified mechanic

      • MOONSHADOW 1918
        MOONSHADOW 1918  4 days back

        Nice wheelie on the FORD

        • Project Farm
          Project Farm   4 days back

          lol. It can get a little too exciting in the old Ford at times!

      • MiscerVids
        MiscerVids  4 days back

        I had a 2006 altima that I ran synthetic in from the first oil change. I used the good stuff, but it did not keep my seals fresh and plyable. I started noticing, a few years later, that I was losing oil, but I could NOT find the leak. Eventually I found the o-ring for the crankshaft position sensor behind the engine (between the engine and the firewall) was where the leak was. When I pulled it out, that o-ring was toast.

      • t
        t  4 days back

        My father worked on big gear boxes and different large machinery the factory he worked for converted to synthetic oil several years ago they had some gear boxes with old leather cr seals that been in stuff for years any ways on some of the boxes they did find that seal life was less with synthetic oil but seals are lot cheaper then gears and the boxes ran cooler and gears and shafts had less wear and they change the oil a lot less in them. My thought on why the seals in synthetic leaked sooner then normal oil was that the normal oil had some chemicals that would soften seals at about same speed the rubber would harden from the heat or to make up the slight wear different. We are talking over a years not just being added and ran a few weeks and the over all was not a huge difference in how long they lasted the old cr seals out live any rubber seal it seamed since think how long ago they had to have been put in but he did notice a different on what how long seals lasted it could also be seals quality was going down on new seals around d same time change oils over but they did have stuff with normal oil still still lot of factors could be affecting it. Could also be the little bit of build up the oil leave on the shaft sealing it

      • Mike Lockwood
        Mike Lockwood  4 days back

        Thanks for your videos. My experience is with the first vehicle which I bought as a new purchase, a 1991 Honda CRX. I ran that vehicle for more than 250,000 mile before I gave it away. From the first oil change, I ran Castrol Syntec at a weight greater than the recommendation. After that I ran Mobile One Synthetic when I paid for oil changes. When the mileage got into those high ranges, I started getting consumption. Power washing with Purple Power showed seepage at every gasket and seal I remember. A switch over to conventional oil stopped all that seepage and leaking. That engine was still purring when I gave it away.

      • Steve Theone
        Steve Theone  5 days back

        I have had leaks on cars with the old rope seals. differant molecular structuer of dino vs synthetic.

      • Xannax
        Xannax  5 days back

        Amazing timelapse drone footage, really love the effort you put into your videos! Your videos helped me choose Amazon Basics oil over Mobil 1.

      • Ron Osga
        Ron Osga  5 days back

        Using detergent oil in an old tractor that was designed to use straight weight oil, will cause it to smoke and leak. In my experience I use semi synthetic oil in newer engines because it seems to tolerate moisture contamination better. Great video

        • Project Farm
          Project Farm   4 days back

          Thank you for the feedback. Does the old tractor have an oil filter? Thanks again!

      • SetTheCurve
        SetTheCurve  5 days back

        This channel has totally sold me on synthetic

        • Project Farm
          Project Farm   4 days back

          Thank you! I'm using only synthetics too after seeing the huge difference in performance

      • Jason Dutter
        Jason Dutter  5 days back

        I have been a mechanic consistently for 46 years. I really enjoy watching these videos. Awesome at several levels!!!!

      • Jeremy Clauser
        Jeremy Clauser  5 days back

        Damn good work! Thank you for your Time and Effort