Mobil 1 Synthetic Oil question.....

[Alexxn 00 Si]

On a 2000 LT with 60K.

Yay or Nay ? I've heard about the myth of how switching to synthetics on higher mileage vehicles causes oil leaks but according to Mobil:

Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.

ExxonMobil engineers are wary of conventional oils that tout their use of additional seal-swelling agents. With extended use, these agents can over-soften engine seals, resulting in leaks. More to the point, an oil additive will not rejuvenate worn or damaged seals. The damaged seal may have been caused by a worn rotating metal component in the engine.

If an older engine is in good condition and does not have oil leaks, Mobil 1 with SuperSyn™ provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1 with SuperSyn™. ExxonMobil also always recommends following the automobile manufacturer's manual for the proper oil to use.

What does everyone say ????

Thanks

[astrnmrtom]

Alexxn:

1st, this is my opinion only, and is worth every penny of what you pay for it

I use synthetic oil in every vehicle I own - see list below - including my daughters ex-old Neon with 115k on the clock (before she totaled it, but that's another story) Now I use it in her Cavalier with 90k on it.

I've been a fan of synthetic oil for years. Origonally because of its higher loadbearing, and heat resistant specs. About 5 years ago I purchased a motorcycle which helped re-enforce my belief in synthetics. It's a '86 Kawasaki concours with 70k - the perfect test vehicle for oil. The transmission in this bike is notorious for being VERY picky with oil. Use the wrong oil and the shifting is sticky and clunky. The right oil and its smooth and quiet. This bike LOVES synthetic oil! Even some of the "best" regular oils only lasted a 1000 miles or so before the shifting started to stiffen up. The synthetic oil thread is one of the largest and hottest topics on the bike's forum infact.

As to your leak worries, I have not had that problem. My bike, the Neon, our Cavalier and my '83 motorhome have some very small leaks. Not the kind that leave drips on the floor, just oily spots on the motor below the front or rear seals. NONE leaked any worse after switching to synthetic.

Now, some things to keep in mind, if you are thinking of switching.

1. COST - many opponents to synthetics say they are not cost effective unless you use extended change intervals. I don't, I change my oil and filter every 3k with the exception of my wife's Rav4 which I change every 5k. She commutes on the freeway every workday and cranks up the miles pretty fast.

2. Using regular oil and changing the filter and oil every 3k is already a great step you can take to help assure long engine life. Many argue the additional cost of synthetic over the life of the engine isn't worth its additional and arguable benifits. They say you throw that extra $2 or $3 out with the used synthetic oil because regular oil breaks down very little in 3k anyway. Most synthetic manufacturer tout extended oil change intervals because of sythetic's reputation for holding up longer because it is more stable under high heat leads and resists acidifying by exhaust gases that blow by the rings.

Ok, that said, I'm ok with the additional cost for synthetic. The way it works in my bike convinces me it is a better lubricant for my cars. I feel if those gears and dogs slip together easier, then the pistons, rings, rods etc are slipping by eachother easier too. Who knows.

I have discovered a cheaper alternative to Mobil-1... Walmart SuperTech Snythetic yup, you read it right, Walmart. Instead of nearly $5 a quart, this stuff is a little over $2 and my bike likes it as well as Mobil-1 or any other name-brand synthetic oil - proof enough for me. Because I own so many vehicles, I buy this stuff by the case and grab oil filters on sale for $2.

Well, there ya go. One person's opinion. Just remember what my dad used to say: "Opinions are like A** holes, everyone has one, and they all stink!"

Tom
'02 SBlazer Extreme 27k
'01 Toyota RAV4 50k
'86 Kawasaki Concours 70k
'99 Chevy Cavalier (with 90k)
'83 Class C Motorhome 35k(!)
Add the boat, lawmowers, edger and trimmer, and you know why I feel like a full time, home mechanic!!!

[Alexxn 00 Si]

Hey thanks for the reply.....I have always used synthetics myself, however I always started using them in my vehicles just after they were broken in new....I've never had to start with a vehicle with high mileage before and there was that myth about it causing leaks always flying around.......the cost doesn't matter at all to me so I think I will go for it again.

[candywrapper]

Hello;
I drive a 99 S-10 Blazer ,It has on around 53,000 on it , I changed over to Mobile 1, 2 weeks ago. I also went with a Extended life Oil filter(7000 mi)filter
Walmart carries them. With the oil , I put in a engine additive with it called IXL anti-friction metal conditioner. Website;www.ixldave.com
I plan on puting on around 5000 to 6000 miles before oil change,depending on how dirty the oil gets. I seen great improvements with the Blazer ,easeir starts, faster starts. faster acsellerations,quicker responces .the milage was the best i seen. I went from 17-18 to 22-23 MPG. I was Impressed. I am a firm believer in Mobile 1 . I usually drive around 200 to 300 miles just on the weekends just loafing.
this my 3 cents worth
Don

[astrnmrtom]

You're welcome.

I think the leaking rumor has to do with synthetics oils better flow properties? I remember reading somewhere - so take this with a grain of salt - that synthetic flows better and therefore can creep through smaller cracks and holes. It doesn't really affect the seals or gaskets, just is more able to get past worn ones. If this is true, switching back to regular dino-squeezins should reduce the leak again.

Dunno cause I haven't had the problem.

Tom

[astrnmrtom]

Additional synthetic "leak" info.

The other reason some folks report leaks showing up after changing from dino, is synthetic oil's higher detergent properties. Over time, the synthetic oil disolves away some of the crud in an older engine, crud that may be sealing small leaks. Remove the cruddy plug, and you have a leak.

Tom

[joker_of_01]

the reason synthetic oil leaks is because when you compare the molecules between synth and crud. it's like BBs to gravel. synthetic oil isvery small and uniform where as crud oil is somewhat larger and not uniform.

[wolfox]

Synthetic oil will certainly leak from an engine that already has leaks. It *may* cause leaks in an engine that never had them before, because as stated above, it will clean out crud that conventional oils leave behind. But once the area is flushed, they often re-seal again. When I first got my Blazer, it got flushed with Gunk oil flush at a hot idle for 30 minutes. It was drained, and saw two quick oil changes with Shell Rotella 10w-30 conventional heavy duty oil. (HDEO or Diesel oil as it is also known by - it's a mere $12/gallon jug and *cleeeeaaaans* way deep as you drive, slowly breaking up stuff that the "shock" flush may have missed) Once those changes were done, I switched to Mobil-1 Super Syn 5w-30 for 6000 miles. She developed a very slow leak that would leave 2 drops on the pavement if left overnight in one place for about 2000 of those 6000 miles. Then just as it appeared, it disappeared. Peeking through the valve cover after removing the oil filler neck, she was spanking new clean inside. I have since then swapped Mobil-1 for Castrol Syntec 0w-30 and she's super quiet, smooth and leak free at over 148K miles on the odometer.

You have nothing to fear by switching to a good synthetic oil at any stage in your engine's life. The only caution I have against the switch is to monitor your oil consumption over two, 5000~6000 mile oil changes. She *might* consume a little at first and it will taper off as the piston rings also clean up and reseal properly. But if the engine already has weak rings and consumes conventional oil like you had a straw connecting the oil sump to your intake, I suggest a rebuild, or running her until she drops on any old cheap conventional oil. Synthetics hands down - I would put in all of my non-consuming, well maitntained vehicles without hesitation. If you have major leaks that loose you, rather than burn/consume oil on a conventional oil fill, get them fixed before you switch to synthetic so you gain maximum benefit from them. Oh, and shop Mobil-1 with a good eye on labels. They come in different flavors depending on how old the stock is. Mobil-1 Extended Performance in 5w-30 makes for a good year-round fill in these engines. If you see much heavy off-road or heavy throttle use of the truck, even 10w-30 Mobile-1 Extended Performance may be used. The Mobil-1 formulations of 5w-30 is a teensy bit on the thin side and under heavy throttle, high load/demand, will slip right by rings no matter how good your engine/piston seals are and will be consumed. The slightly more robust 10w-30 would be a better match if you're a rough and tumble truck driver that plays in the mud and rocks or likes spirited driving. It's mildly thicker constituents will not as easily slip by the piston rings and makes an awesome year-round fill-up down to at least -30 degrees.

Okay, that's all off of the top of my head, and I left a lot of information out, but how can I wrap this up? You *can't* go wrong by switching to synthetics now, or later. Feel-out how the truck behaves, and be tollerant of leaks for the first oil change. She should clear up as soon as the seals clear out and hold the crankcase full of that good stuff for the whole oil change if everything's ship shape. There are many other benefits to using synthetics, but I will hold off with flooding you with the how's and why's until someone is interested and asks. There is such a thing as too much information at one go.

[Rmbodie]

I too am a fan of synthetics , Although I use Castrol. I tried mobil 1 once about six years ago because of price and my engine seemed louder at an idle like the valvetrain was rattling . I was afraid I had damaged something during those seconds before the new oil gets thru the system . But at the next oil change it still sounded like that and I went back to Castrol of the same weight and the rattle went away . I added it to my blazer not knowing what kind of oil the previous owner was using and have not had any oil leaks . But sythetics are suppose to penatrate into the metal . Another one of their benifits . Rob

[muzzy1maniac]

I would hardly call 70k miles on a well maintained vehicle "High mileage". I started Mobil 1 when I bought my Blazer w/71k on it and have never had a problem. No leaks, very little consumption. Since I drive highway about 99% of the time I do changes every 10 - 12k miles with a filter change and top off @ 5-6k.

[BlazerBoyLT98]

I use the Mobil 1 15K oil change interval oil that is supposed to have more supersyn or whatever it is and I use 5W-30 with a wix or fram X2 filter. Over the winter months I may switch to a the same oil but drop down to 0W30. I too notice a small oil leak and small consumption the first 3 oil changes ( I change every 5-6K) but now it is gone. I put anywhere between 25 - 30K a year on my blazer and since I have switched to synthetic I will never go back.