I've been using synthetic blend , but heard full synthetic is better.

What aspects will full synthetic oil do for my aging es 350 (2008, 170k miles)

Can I space out oil changes to longer durations?

Thanks!

 

Full synthetic is not that much more expensive than the blend, and oil changes are relatively cheap now that it's almost not worth it trying to space them out more.

 

Full synthetic is a marketing term, most oils sold are labeled as full synthetic, which are only group 3 hydro cracked oil most of the time. This engine is very easy on oil, and for 5K OCI you can run any oil you like.
I recently had Mobil1 Extended Performance for 10k miles. Car was driven mostly city and almost one year between oil change. Sent sample to Blackstone labs, and they said oil was still good and recommended to try 13k miles next time

 

not convinced full synth is a marketing term, but still listening. there is a lot of discussion on oil over at BMW forums, and BMW specifies it in some engines. BMW if very, very particular on how cars should be maintained or repaired. all of leads me to believe full synth is a real thing.

 

Full synthetic is better in cold temperatures as it retains its low viscosity at lower temperature than regular oil, not sure about blends. Also full synthetic can be found in high mileage variants which include additives for oil seals - helps extend the life of gaskets, etc.

With 5k mile oil changes any good oil seems to last the same. I have a hard time finding anything other than full synthetic and the price is relatively low to not go with anything else.

 

Its what you want to believe. The facts are that after lawsuit in 90s between mobil1 and castrol they allowed calling group 3 oils synthetic, which according to german law can not be called synthetic. In Germany only group 4 oils can be called synthetics. This is the reason synthetic so cheap, and you will have hard time finding oil that is not labeled synthetic.
if you want group 4 oils, prices will double:. Revenol, Amsoil, redline and few others

If you plan to run 5k oci, any 5w-30 will work, synthetic or not.

 

My OCI is 5K miles, TGMO 5W30.

 

I can tell between synthetic blend and whatever I want to believe as synthetic. Big difference in oil smell (fumes), OCC residue, and also during idle, the engine is way smoother. All the above are more distinct during the winter months.

Amsoil Blog
* is from the internet, so is prolly true 😅😜

 

This is specified for my M6/S85 engine: https://www.castrol.com/en_us/united...es/10w-60.html

Also tried Liquid Moly last oil change (which occurs about every 1000 miles)

Let me know if there is something better, and if these are horrible to run for an engine that revs to 8500 rpm.

BTW - I think you'll be hard pressed to prove Mobil 1 5-30 is a pure Group IV synthetic.
https://blog.amsoil.com/are-all-synt...ii-vs-iv-vs-v/

 

most of Mobil1 oils are not group 4. Unlike Amsoil, you can get more information from Mobil1 SDS docs. Last time I checked some of them had 20-30% of group 4.
amsoil does not promise anything, could be group 4 or group 3, or both

 

What? hell NO!

It is never ever the same, like I said, I can tell by looking at the OCC residue, the oil smell after 5k, how the engine idles etc.

 

oil smell, is this some woodu ***** ? Send it to the oil analysis lab for objective results, and show us the proof that non-synthetic oil does not work for 5k OCI.
owner manual says 5k oci is good on dino pil

 

I did not say conventional oil will not work, I am saying it IS NOT the same thing in oil quality

Oil smell is more than enough, I can tell the oil is getting cooked with hi temps, while full still smells as new, obvious sign it is resistant to extreme heat.

You forgot OCC and smooth idle. The oil in the can is clean, if it is semi synthetic is foamie w a stench smell. It happens more under extreme cold temperatures, only w conventional and semi synthetic.

What is your basis about 5k intervals?
lets see your lab results...

 

I run mobil1 5w-30 ep with 10k OCI, blackstone laba said it was still good

 

I started looking around for group IV oils. Thanks for pointing this out btw, didn't know about this. Its seems that 60% is about as high as they go. Mobil 1 0-20 is one that is higher and sounds like getting lower. Also, it looks like Liquid Moly another that gets to 60%. That blend, may have something to do with start up, cold lubrication. I heard from a pretty knowledgeble guys to not let water get into your Liquid Moly. It could be the POA. Of course immediately everyone asks him how the hell does water get in your oil, his response was it happens.