So my car has about 110k on it and I've been using Mobil 1 its whole life. I'm wondering if I should switch to the Mobil high milage oil or just stick with the 1.

 

Eh. Synthetic oil is just better oil, I personally don't believe anything I'm told about additives in high mileage oil that make it better. Synthetic ftw in my opinion.

 

Stay with Mobil 1.

 

is it true that if a car has high miles and you switch to synthetic, it could dry out the seals in your motor?

 

NO

Stay with Mobil one. It will protect alot better than any type of High mileage motor oil

-matt

 

Castrol 0w30 is much better than Mobil 1.

 

Heres a question:

Why is synthetic oil better than regualar oil?

I know that with some synthetics, you can go longer w/o changing the oil but what are the real advantages. I do not plan on using syntheic because I just bought the car with 108K miles and do not believe the previous owner used it.

 

true synth cleans. where dino just keeps clean. longer OCI. reduced wear. better flow (especially at cold starts). true synth wont sludge (unlike dino). increased resistance to oxidation shearing etc.

 

Castrol GTX for our cars, at high mileage just keep feeding the car what its used to, don't change the winning formula. as long as the intervals are properly maintained, i dont think it even matters what oil filter you use as long as the oil is Castrol GTX

 

Actually Mobil 1 just came out with an all synthetic oil for high mileage cars. I dont know how it compares to their reg oil but I seen it at the store the other day.

 

Is it true that because synthetic oil cleans you could start leaks that normally your dino oil didnt I guess open up? Someone told me this so I never used it.

 

Slim chance but possible. If sludge is currently plugging up already existing gaps in gaskets (caused by the buildup of sludge itself), then using a good synth may clean that sludge and allow the gaps to be exposed. There is a product out there That is said to totally clean the motor and recondition seals. I have tried it on a couple of cars. It works. www.auto-rx.com

 

But if the gaps are now exposed, can't this lead to an oil leak?

 

It can if the gaps are there. But i would rather a leaky clean motor that may need some new gaskets than one so dirty it cant leak. That and once it is clean, there are reconditioning products out there.

 

I've always used castrol gtx and i'm at 183k with no leaks or smoke. Just stick to what you use and you will be fine.

 

If a seal is going out, it will tend to leak earlier/more than with conventional. That's just life. The high mileage oils do tend to slow down the leaking.

I have a slight seep at my rear crank seal (I think) and I'm using Mobil1 10w30.

Dave

 

I won't weigh in on the type of oil issue, but I've used Auto-RX and it is great.

 

I got 220k on my motor and it's had mobil 1 for most of it's life up until now. I ran an auto-rx treatment and switched to 0w-30 synthetic german castrol. It still pulls just as good as it did when I first got it if not better.

 

I have been putting mobile 1 full synthetic since I bought my car used at 43k miles and now have 94k. Since i have another car now, i only use this for commute and only drive about around 400 miles/month 90% local in NYC. How often you guys think i should change my oil/filter? It would take me whole year to rack up like 5-6k miles. SO i guess i should change it every 5-6 months?

 

Not with that stop ang go city traffic you guys have there, and then you have that race from light to light

 

I would go HM oils if I were u. I have been using HM oil on my maxima with 120K on the odometer.

The only thing about HM is it is SL rated not SM, other than that the additives are top notch, why would you have all oil companies have them in the first place?

 

http://www.blackstone-labs.com/free_test_kit.html
the only way to know if you are going too long or too short with your oil. can also indicate a coolant leak. best $20 you can spend.

 

Well said 2da_mizzax, best $20 one could spend every 30k miles.

If you are a AAA member, AAA provides services for testing used oil. I get my oil analyzied by AAA.