HotMax28

I've heard that putting synthetic oil in a high mileage engine is not cool. I know it does wonders for the car but I was just wondering if this was true or not. I have 150k in mine. Should I be alright with Mobile 1?

brubenstein

If your engine doesn't burn/leak oil, and is pretty clean inside (regular oil changes) there shouldn't be any problem with switching to synthetic. I would, however, be more inclined to use Valvoline Max Life which is made for high milage engines. see: http://www.valvoline.com

94SUPERMAX

I put Castrol Syntec in my car today but the day before I put in some ATF and cheep motor oil to flush the engine I don't use the engine flush products they do more damage than dirty oil. I ran the car for 15 min and drained all the dirty fluid out then I put in the cheep oil and drove it for a day just to get rid off all the dirt and ATF. Today I drained the cheep oil changed the filter and put in the Castrol Syntec oil. There is a difference right away. I also changed the air filter and spark plugs.

HoJo

I just started puting Mobile 1 in my car, at 120K, and everything is fine. Doesn't burn any.

BippuBenji

iTrader: (4)

I've been using Valvoline Max Life for the past 15,000 miles and that was around 60,000. Since then, I haven't been came across any problems. Starts like new in cold weather and never seems to give me any hesitation or stalling.

Zprime

Go for it!
it does not break down as easy as dino during hard driving condition
it is supposedly makes the engine rev easier?...ok...I dunno much about that...maybe something with vicousity..
it does good...
now...if you are worried about leaks...
I decided to put synthethic about a year ago...note that the previous oil changes were done by the first owner...who knows where and how often, but at her mileage now (pretty darn high...close to 100 K) No problemo...no leak..no oil burning
Yes thats my baby..95 max...with a pretty darn high mileage...I think the first owner travel back and forth the highway or something....just for fun...
^_^
if you are not confident. don't risk it....
I decided to go ahead because if my car leaks when I put syn oil in it...that means my engine needs rebuilding anyway (maybe I am wrong)....but luckily...it is still strong...preferrably until 200K or something...then rebuild or retire the thing
heheheh...

bill99gxe

iTrader: (1)

so many different opinions on this subject that I don't know what to believe.

I can tell you the primary concern is your engine oil seals. Some believe that a synthetic oil would actually break down these seals if regular dino oil has been used. Others say this is hogwash. I would fall into the hogwash crowd, provided your engine does not burn/leak oil as brubenstein has already stated.

I bought my 94 with 35k on it. I immediately switched to Mobile 1 and ran it to 86k in 10k change intervals (with Mobile 1 oil filters). Then, I went with <A HREF="http://www.ulx110.com">ULX-110</A> (highly refined dino oil) for 20k, with a 12k and 8.6k interval as well. I had this oil analyzed with the 8,600 mile interval, and the oil could have gone further according to <A HREF="http://www.blackstone-labs.com">Blackstone Labs</A>. Then, I ran Amsoil engine flush through the car and immediately changed to <A HREF="http://www.amsoil.com">Amsoil 5W-30</A> at 106k.

The point is, through this whole process, I have never lost a drop of oil in my 94 or leaked any either.

Mobile 1 should be fine at 150k, but it would be a good idea to have your oil analyzed by a place like Blackstone Labs, since your oil will tell you how well your air filter is working, oil filter, gasket condition, etc.....

Sprint

iTrader: (10)

I don't know if anyone has said this to you already but Castrol Syntec oil is not true Synthetic Oil

HotMax28

I have a slight leak where my transmission connects to the engine, would this cause any problems with the synthetic?

Guest

It seems that your rear main seal is leaking. I would be hesitant to switch to synthetic in that case. Replacing the rear seal is expensive!

Jeff92se

iTrader: (82)

That sounds like a main seal oil leak. That would get worse if you switch to synthetic oil like 0-30 or 5-30. You probably have to use 10-30 and even then it might still leak.

RussMaxManiac

I hvae a friend that had 91 SE 5spd Max, when he switched from dyno oil to Mobil 1, and he did do 3k changes, it sprung one leak, and also when it was cold it started to knock for the first min. I think its not a good idea personally.

HotMax28

my shop said it would cost like 50 bucks to replace the seal but the labor to remove the transmission to get in there would be like 400.