So it's about that time for an oil change. I have 5w-30 full synthetic Mobil 1 that i got for free from a friend. Now my dillema is that during start up I sometimes burn oil leading me to think that is due to my valve seals. Now i am wondering if with this full synthetic oil, it will burn more upon start up as to the non synthetic 5w-30 in the engine now. So should I use this full synthetic 5w-30 or go up a weight to 10w-30 non-synthetic, or full sythetic?

 

Not sure what cleaners and conditioners they use in Mobil 1. But simply synthetic is a "thinner" oil than conventional. If anything it would be worse in my opinion.

I know switching to synthetic can cause an engine oil leak just due to the thin oil slipping past seals. Probably wouldn't help.

 

So what oil do you think would be best? Im thinking conventional 10w-30

 

Throw in some Walmart 10W30 or 5W30 and change it every 5000 miles

 

To be on the safe side I would do as suggested above . You could even use a drive through change with a $19.95 special running.
But.......When I bought my car the obdomiter read 95,000 but it could have rolled over once.
Any way the first thing I did was replace the oil with Mobil 1 XP 5w-30 Synthetic.
The car used to have a puff of smoke on startup with worn valve guides.
After about a year it was gone.
I have been using it for over 9 years with no problems.


. I'm not saying that others have not had a bad experience with it .That's just what happened with me so maybe I just got real lucky.

 

What I would suggest is use 10w-30 Mobil one full synthetic. Orrrr you could also use the Mobil super 5000 high mileage synthetic blend to combat the puff.

An by the way never go 5000 on a conventional oil. Only 3months or 3000 miles which ever comes first. Or a full synthetic 6 months or 6000miles. Synthetic blends 4 1/2months or 4500miles.

I work at a GM dealership an this is what we recommend. Some of my techs even say 7000miles on the full synthetics but that just depends if you do a lot of freeway.

But for your puff I say you put the synthetic in at 5w-30 then try the 10w-30

EDIT: MEANT to say since you put the 5w-30 synthetic in go ahead an put the 10w-30 full synthetic in now

 

Iha raises a good question - Why 5W-30 in an application which specifies a higher viscosity?

 

5W-30 in my case is what was suggested by Mobil 1.
I live in "Wine Country" so it a very mild winter and just right in the summer so I guess I could jump up to 10W-30. Since the car has been running the 5W-30 for 9 years now, will moving up to a 10W-30 be OK.

 

When these engines were new General Motors actually said put 5w-30 in them due to efficiency an all that stuff but if you look in the service manual it actually says if you live in a warmer climate use 10w-30 an being you live in California use the 10w-30. I'm originally from Mississippi an we used 10w-30 year round an I still do even up here in Washington state. 5w-30 even though at running temperature is 30 just like 10w-30 is, 10w-30 will actually be a bit thicker due to the bigger difference in numbers like 5w-30 is.

Check out Bob is the oil guy forum for oil stuff also if you'd like to learn more about viscosities of oil. I could go on an on here telling you about oil analysis an what not haha. But for you being down in California use the 10w-30 in your car it won't do nothing.

 

5-30 is 5-30 weight is weight a thinner oil would be 0-20 valve seals leaking will burn any oil need to replace seals... full syntectic is made in a lab. synthetic blend is half synthetic half convential... convential come from ground
i would run whats recommened if you want to learn heat ranges on oil google it i change my oil in my DD every 3000 regardless my engines are SPOTLESS INSIDE oil changes are pocket change compared to new engines
toyota recommeneds 10,000 mile on there full syn. cars remember new cars run ALOT cleaner, oils run different in new engines than our 3rd gens and they have to meet mpg requirments
synthetic oil doesnt breakdown nearly as fast as conv. oil

 

If you don't have a cat run diesel oil and if you really want protection run valvolines VR1 40

 

I use the Extended Performance Synthetic Mobil 1 and EX larger M1-302 filter and drive the car about 3,000 miles a year. Its Christmas Present is a oil and filter change.

 

I use Rotella 10w-30 and Lucas oil stabilizer in mine. Always change around 3000 miles and every few oil changes put a couple ounces of sea foam in there. The sea foam will help clean deposits that the oil can't clean out.