High Mileage Oil....worth It? You Bet!

[lexusnutt]

Hey all!

I want to share with you my experience with my '95 LS400 with 140K on her...

When I first got it back in August, I wanted to treat it to Mobil 1 even though I read many posts on how syn oil may loosen seals and create a leaker. Well, afterwards, leak it did..... Not only that, but the valves seemed to be louder. My heart just sunk! :cries:

I did some research and decided to try a high mileage oil (Castrol). The leak gradually diminished and after 3000 miles and a second oil change, the leak stopped! The valve noise was gone too.

IMHO, I would recommend against using a synthetic in a high mileage car that has always used dino. It's just not worth the possible stress!

Cheers to all!

Chuck

[SKperformance]

Don't they have high mileage synthetics?

High mileage oils usually just have more seal conditioners and viscosity thickeners which can be done with any oil including synthetics.

[mburnickas]

Don't they have high mileage synthetics?

High mileage oils usually just have more seal conditioners and viscosity thickeners which can be done with any oil including synthetics.

Yup you are correct.....the problem is that if you have leaks with synthetic (many miles) and go back to dino to stop it, you have false seals to begin with. Means you have carbon, sludge etc in your engine.

You need an add like Auto-RX or LC20 to condition the seals properly. Using a high milage oil is a temp fix at best.

That is the way I take it.

[lexusnutt]

Don't they have high mileage synthetics?

High mileage oils usually just have more seal conditioners and viscosity thickeners which can be done with any oil including synthetics.

SK,

That's an excellent question that I never thought of. Unfortunately, I've never seen it at the local Kragen.

Has anyone on this board used a high mileage syn with any success???

Cheers!

[SRK]

I have put Mobil 1 5W-30, and every other viscosity they make, into so many different cars at so many different mileages, and into all of my cars, without so much as a single problem. As SK says, the "high mileage" oils have seal swellers in them. Problem with that is, the seal swells continuously until failure. Have a look inside an auto tranny that has had "stop leak" put in it. The seals are huge and distorted when removed.

A customer of mine has a 1969 Ferrari Daytona, original engine. I put Mobil 15W-50 in that thing five years ago. No leaks, not even past those cheesy Italian seals.

Go the the Mobil Oil website and read the truth, and ignore the myth.

And just to get this thread really revved up, I wouldn't use Castrol in a lawnmower. Maybe on a door hinge...

[wwest]

I have put Mobil 1 5W-30, and every other viscosity they make, into so many different cars at so many different mileages, and into all of my cars, without so much as a single problem. As SK says, the "high mileage" oils have seal swellers in them. Problem with that is, the seal swells continuously until failure. Have a look inside an auto tranny that has had "stop leak" put in it. The seals are huge and distorted when removed.

A customer of mine has a 1969 Ferrari Daytona, original engine. I put Mobil 15W-50 in that thing five years ago. No leaks, not even past those cheesy Italian seals.

Go the the Mobil Oil website and read the truth, and ignore the myth.

And just to get this thread really revved up, I wouldn't use Castrol in a lawnmower. Maybe on a door hinge...

I'm in entire agreement with EVERY word.

[SKperformance]

As am i , nice to see a oil thread with everyone on the same line.

Mobil 1 is basic protection while redline ,royal purple and motul are much higher end ones.

[mburnickas]

As am i , nice to see a oil thread with everyone on the same line.

Mobil 1 is basic protection while redline ,royal purple and motul are much higher end ones.

Due to price reasons of Amsoil (yet again), I will be using Mobil SUV or Mobil 1 SS in my Lexus...so there! :D :D :D

[blake918]

I switched my high mile (230k at the time), dinsoaur running '95 over to M1 SuperSyn (their regular blend of 10w 30, no high mile addatives for me.) over two years ago without a single problem. We're now at 277k with nothing but great things to say about Mobile 1 synthetics! :D

[lexusnutt]

Wow! It sure seem unanimous with M1. The car was not maintained well before I got it, so maybe that had something to do with it. I really believe there are many factors in car maintenance from the mechanic, to quality of parts, to the condition of the car itself. No two experiences are the same.

I hope you can all understand my frustration... I've been a believer of M1 (use it in my 2001 F150 from day 1) with no problems. However, I've read many posts, not just here but on other boards that using M1 on a high mileage engine can result in seal leakage. I took my chances and experienced just that. The HM oil solved my issue and hopefully I can gain another 100K without any problems

I have to tell you another thing I did that may go against the grain of opinion here.

My transmission fluid was orange/brown and I thought about replacing it 2 quarts at a time or so as is the general consensus on this board, but it was so bad it would have taken a year to renew.

So, I flushed my tranny (yes, flushed). It took 24 quarts before it was clear but it now drives like new! It's been 6 months, no leaks and the fluid still looks the same. I know I was probably lucky, and in no way am I endorsing flushing one's tranny, but heck, it worked for me and information needs to be shared!

One thing I do know is that the knowledge gained from this board has been invaluable and I thank everyone for their input!

Cheers!

[bartkat]

We used to put straight 40 or 50 weight oil in Chrysler flathead sixes just to keep the oil pressure up after they warmed up. Also had to add a quart or two every 1000 miles or so. Bought the stuff in 2 gallon cans and kept it in the trunk.

As for Castrol, I haven't used any other oil brand in any motors for 35 or 40 years. Never ever had a problem with any of those engines. Back in the day theirs was the only oil that didn't gum up and carbon up the engines on our dirt bikes. When oil injected motors came along, Castrol synthetic was the absolute best. Ain't nobody gonna convince me that Castrol isn't good stuff.