The problem with your car was the inferior "valve guide seals" which allowed the superior synthetic oil to deteriorate them. If that was a Mobil 1 problem, we would have heard of thousands of cars with deteriorated valve guide seals.

 

The problem with your car was the inferior "valve guide seals" which allowed the superior synthetic oil to deteriorate them. If that was a Mobil 1 problem, we would have heard of thousands of cars with deteriorated valve guide seals.

I'm not following the logic of this thread unless you're saying there were reports of thousands of Tercel's with reported valve guide seals, since using regular oil would have protected them less better than Mobil 1?

 

All I'm saying is that if Mobil 1 killed valve guide seals, we would ALL know it. It would be public knowledge, and Mobil 1 would have the associated "black eye."

Since we know that has not happened, it's hard to blame Mobil 1 for damaging an engine in any way.

User schmidtj might have a valid reason for blaming Mobil 1, but I cannot agree with him. Millions of drivers have used Mobil 1 for probably billions of miles driven, and if Mobil 1 was killing engines, it would be common knowledge.

 

Well at the time I switched to Mobil 1 synthetic oil's were rather new. I don't think a lot of Tercel users actually used the stuff.
I am basing my blame on what the dealer told me. Perhaps the dealer's statement was selfserving and I was ignorant.
Interestingly, I just did a google search and it is NOT unheard of for Mobil 1 and other synthetic motor oils to have damaged valve guide seals in the past. Supposidly it is no longer an issue as manufactuers use a different seal material these days than then did 20 years ago.
I'm sticking with 3k oil changes using the manufacturer recommended oil.
J

 

Now THAT makes much more sense - the part itself failing because the material it was made from was unsuited for synthetic oil's superior properties. That I can live with !!!

 

I guess I just have a problem with referring to a product as "superior" if it can cause damage whereas the "inferior" product doesn't.
Not trying to start any kind of pissing contest here btw.
J

 

I'm a big synthetic oil proponent, and I'm just trying to get to the bottom of the issue.

I Googled "valve drive seals" and "mobil 1" and found no one who says they put Mobil 1 in at 5,000 miles and suffered valve guide seal damage attributable to Mobil 1.

It appears that what happens is the thinner synthetics EXPOSE valve guide seal leaks which are caused by previously damaged or inferior valve seal components. Certain types of valve guide seals can be damaged by any petroleum product.

Maybe Toyota just used a poor or cheap seal on the Tercel. Maybe they got a bad batch from the supplier.

My point is that if Mobil 1 ROUTINELY damaged different engine parts more than standard dino oil does, we would know about it.

 

Engine seals are designed to swell slightly in contact with conventional motor oil (especially back years ago when engine tolerances were not as tight as they are today). Early synthetics did not cause this effect which resulted in seals leaking. Later synthetic formulations added a seal swell additive to compensate.

 

Thanks for that Andy.......

 

That restores my faith in my Toyota dealer.
FWIW the reason I even tried Mobil 1 was I was under the mistaken impression it was made not using oil or more specifically imported oil. I now realize this is totally not true. Synthetic oil is make from oil both domestic an imported. The synthesizing is just reorganizing the molecules of natural oil.
Back when I owned the Tercel and after the seals had failed ...
I wrote a letter to Pennzoil asking if their oil which was made from "Pennsylvania Grade Crude Oil" contained any imported oil compents. I received a nice letter back from them saying tha PGCO must come from Pennsylvania and New York and have a certain Parafin component and did not contain any imported oil . I then switched to Pennzoil. I think this has subsequently changed so I just let the dealer do the oil changes put what ever it gets in it's 50 gallon barrels. If any issues come up about what oil I use they can't point the finger at me. Somebody jump in if they know Pennzoil is not made from imported oil.
J