I know our SC300 owners manual says - 5K between oil changes.

I just switched to Mobil 1 for the first time - it's been over a year since it was done, but still only has 4,300 miles on it.

My question is - how often shall I change the oil or at how many miles? 5K, 7K, 10K.

I would like to hear from the SC community.

Thanks!

 

I usually use Royal Purple, but its pretty much the same thing. I usually go 4-5k between changes.

 

I used Lubro Moly synthetic, which was great oil, but I recently switched to Royal Purple 10W40 and like it a bit better since I was using Lubro's 5W40. Typically I change it every 3,000-3,500 miles. Honestly, you can go 4-5K without having to worry much, but when you have OCD like myself, you NEED to do it every 3,000ish You definitely do NOT want to go a year on the same oil because it will break down and lost the protection you need. Change it every 2-4 months.

 

It's up to you, the more often you change, the longer your engine lasts

 

I'm "old school" change the oil every 3,000. Oil changes are cheap insurance
for engine longevity. I would NOT use the Mobile 1, Royal Purple is very good and German Castrol-5W 30 is the best I believe.

 

id like to hear your reasoning on this.

 

Mobile 1 Full Synthetic and Royal Purple Synthetic are totally different. Mobile 1 Synthetic is actually conventional three oil and not real synthetic like it used to be. There was a lawsuit between Mobile and Castrol a while back when Castrol started calling conventional three oil synthetic. Mobile lost the lawsuit and decided themselves to jump on the bandwagon of calling conventional three oil synthetic since it is much cheaper to produce and they can still sell it for the same high price.

Companies like Royal Purple and Amsol are two companies that is still true synthetic. There are a few others that still are true synthetic. So if you are using Mobile 1 and similar companies then you should change every 3k miles. Using Royal Purple you can go longer like 4k plus. But with our older motors it is just best to stick with the 3k rule.

 

Lately, I've been using Valvoline FullSyn every 3-4k with no problems.

 

Not necessarily true. The synthetic grp IV-V oils now a days have a very good base oil which will last quite a while and resist high temperature breakdown.

Even the super hydrocracked grp III oils like mobile 1 do a very good job in protecting the engine from wear.

In fact, these oils have certain addatives which actually increase the protection as your oil is used.

Think about when the manual was written. In a day and age where full synthetic was not a common place and the majority used conventional dino oil. In the case of dino oil. Yes every six months and three thousand miles is a good thing to do since these oils break down very quickly in comparison. (i.e. do not hold multigrade viscosity often breaking down to base oil viscosity such as 10w-30 turning to straight 30w or straight 10w oil)

They didnt take into account that a decade or so later the oils we are using now are vastly imporoved.

OP I would do a regular 5k change interval and just keep it at that. If you wan't more out of your oil, I suggest oil analysis to tell the condition of your oil. THen change the filter at around 5k and, if your oil is healthy, keep goin for another 3.5- k miles or so till more analysis is done.

Also to the poster above me. German Castrol is 0w-30 full synthetic. It is found to be an excellent oil in many respects.

 

Yes, Mobile 1 is a hydrockracked grp III and not a full synthetic as advertised in the US. It is still an excellent oil (coming close to full synthetics) but is greatly superior to conventional grp II dino oils due to the excellent addative packs.

There is no "real" reason not to get mobile 1 except for their marketing claims saying that they are full synthetic. For that price you can get a real true synthetic in the form of german castrol.

 

Same here..I use Mobile 1 Synthetic and I change my oil every 2 months no matter what, but thats just me

 

Well, other facts, and opinions about why you wouldn't do what you're doing is on the other posts in this thread.

Whether you believe them is up to you mate.

 

3k or less

 

every 3k regardless of type of oil

 

Mobile 1 and other mainstream synthetic brands are like $21 for a 5 quart jug at Wal-Mart.

It is definitely cheaper than smaller brands like Royal Purple and Amsoil