Engine Cleanliness

[Gene K]

I have a question about engine cleanliness.
I keep seeing the recurring opinion that a "Synthetic" keeps engines cleaner.

I'm a bit confused about the attributes of a Group III 5W-30 "Synthetic" that would make it keep an engine cleaner for a 10,000 mi OCI vs Group II 10W-30 Conventional with a 5,000 mi OCI.

 

[The Critic]

Subscribed. I think any differences, if any, will be a function of the additive package.

 

[OVERKILL]

I have a question about engine cleanliness.
I keep seeing the recurring opinion that a "Synthetic" keeps engines cleaner.

I'm a bit confused about the attributes of a Group III 5W-30 "Synthetic" that would make it keep an engine cleaner for a 10,000 mi OCI vs Group II 10W-30 Conventional with a 5,000 mi OCI.

If a particular design produces deposits from oxidation, Group III bases are more resistant to oxidation than Group II. PAO is of course even more resistant as is POE. The creation of varnish depends on oxidation, so it's quite possible for certain designs that are "hard on oil" to produce varnish on oils blended using cheaper bases that would produce less, or none, on oils using better ones.

All that said, the ability to keep contaminants in suspension, prevent them from plating out onto surfaces and the like is a function of the additive package, so that of course plays a critical role.

 

[Graham Piccinini]

If you click here you will see that the engine that ran only on Royal Purple from new to 36k miles, then Amsoil 36k-151k, still ended up being varnished. OCIs were 6k-7k miles. Thoughts?

 

[OVERKILL]

If you click here you will see that the engine that ran only on Royal Purple from new to 36k miles, then Amsoil 36k-151k, still ended up being varnished. OCIs were 6k-7k miles. Thoughts?

Too long of OCI for the lube or condition of the engine. He said SS and XL, XL is just your Joe Average Group III oil. I certainly wouldn't be happy with that much varnish in my engine.

 

[Graham Piccinini]

Too long of OCI for the lube or condition of the engine. He said SS and XL, XL is just your Joe Average Group III oil. I certainly wouldn't be happy with that much varnish in my engine.

Amsoil claimed that their XL line is good for up to 1yr/12k miles. Royal Purple made similar claims for their API rated oil as well - up to 1yr/12k miles. That is from memory though, remember reading that from Amsoil and RP rep emails here on bitog somewhere, circa 2014-2016ish.

 

[OVERKILL]

Amsoil claimed that their XL line is good for up to 1yr/12k miles. Royal Purple made similar claims for their API rated oil as well - up to 1yr/12k miles. That is from memory though, remember reading that from Amsoil and RP rep emails here on bitog somewhere, circa 2014-2016ish.

RP's API oil was only ever marketed as good for OEM intervals AFAIK. XL "up to" should probably have been followed with UOA's, as in this case obviously there was oxidation taking place. Certain applications just are not good with longer drain intervals, mechanical issues can also cause premature degradation.

 

[Graham Piccinini]

RP's API oil was only ever marketed as good for OEM intervals AFAIK. XL "up to" should probably have been followed with UOA's, as in this case obviously there was oxidation taking place. Certain applications just are not good with longer drain intervals, mechanical issues can also cause premature degradation.

Just looked up the Owner Manual and Scheduled maintenance manuals from Ford. Here is a couple things that I found that give no excuse to Amsoil for that amount of varnish:
- "Synthetic or synthetic blends are not mandatory"
- Recommended OCI is 5k miles with a 5w30 conventional, so even a "simple" Amsoil XL shouldn't have had any issues going an extra couple thousand miles per OCI.

So returning to the original topic of this thread - I think varnish will happen either way, conventional for 5k or synthetic for 10k, unless you pick an oil that is known to pack a punch when it comes to cleaning. Pennzoil Ultra Platinum or Mobil1 0w40 come to mind. Also a small engine in a large engine bay may get less varnish due to less heat under the hood. Vice versa - a large engine in a tight engine bay won't get cooled as well, so will probably end up with more varnish regardless of oil used.

 

[Graham Piccinini]

Case on point: My 2000 Lexus GS300 with a 2JZ-GE inline six engine at 360k+ miles when this pic was taken. Both cams are subjects to same oil and same intervals, but the cam on the left is mostly uncovered and is vented out pretty well with airflow in the engine bay. While cam on the right has an intake manifold and throttle body unit wrapping around it, keeping more heat all around that intake cam, as compared to the exhaust side cam on the left.

Here is what it looks like assembled:

Yes, it has two valve covers on an Inline Six engine

 

[buster]

Depends on the operating conditions, engine type, quality of dispersant package. And detergents. Dispersant's are polymeric and ashless compounds. These compounds hold potential deposit forming materials to keep them suspended in the engine oil. A good III should have higher oxidation resistance than a II. But you're comparing 5k to 10k so it's hard to say. Really depends on the overall quality of the additive package too.

 

[demarpaint]

Here's a fill hole picture from a 2000 Century I was given by my father. He was the original owner and the vehicle was meticuolsly maintained with dino oil changed at the dealer or a local trusted shop. FTR no OCI exceeded 3,000 miles, the engine had about 85K miles on it when I took this shot. No mechanical issues whatsoever. Not very impressive considering the rave reviews dino oil gets from a lot of people. Regarding cleaning it, " a good cleaning synthetic" would have taken a lot longer than I had the patience or time for to clean it up.

Hey @Trav you remember this car?

 

[4WD]

Why dino is becoming extinct

 

[aquariuscsm]

I have a question about engine cleanliness.
I keep seeing the recurring opinion that a "Synthetic" keeps engines cleaner.

I'm a bit confused about the attributes of a Group III 5W-30 "Synthetic" that would make it keep an engine cleaner for a 10,000 mi OCI vs Group II 10W-30 Conventional with a 5,000 mi OCI.

Isn't grp 3 oil just cleaner, more refined dino juice (more aggressively refined crude)? I'm guessing there's just less impurities in it to keep from dirtying the engine.

 

[demarpaint]

Why dino is becoming extinct

Looking at those pictures it's extinct in my book. I wouldn't use it in any vehicle I own.

 

[4WD]

Isn't grp 3 oil just cleaner, more refined dino juice (more aggressively refined crude)? I'm guessing there's just less impurities in it to keep from dirtying the engine.

Dino is just BITOG “speak” for conventional …

 

[Davejam]

I mean we're looking at the top of cam. Does it really matter if there is varnish there? This is more or less static region.
The portion where the lifter makes contact with valve is what's important, and that looks to be better.
I think these cam pictures are much-a-do about nothing unless we're looking at serious sludge.

 

[Snagglefoot]

How about the underside? I dropped the oil pan on 15 year old Ford V-6 with 85,000 miles and things were totally clean with nothing on the pickup screen. I bought it used and am only assuming it had regular changes with 5w20 oil.

 

[Gene K]

I mean we're looking at the top of cam. Does it really matter if there is varnish there? This is more or less static region.
The portion where the lifter makes contact with valve is what's important, and that looks to be better.
I think these cam pictures are much-a-do about nothing unless we're looking at serious sludge.

I'm not sure it's possible for varnish or sludge to form on the lobe of the cam. It's getting polished off on every cam rotation. If you will look the heels are varnished but not the lobes. That may be a mechanical engine but even if hydraulic the heels don't see near the pressure as the lobes.

 

[Trav]

Here's a fill hole picture from a 2000 Century I was given by my father. He was the original owner and the vehicle was meticuolsly maintained with dino oil changed at the dealer or a local trusted shop. FTR no OCI exceeded 3,000 miles, the engine had about 85K miles on it when I took this shot. No mechanical issues whatsoever. Not very impressive considering the rave reviews dino oil gets from a lot of people. Regarding cleaning it, " a good cleaning synthetic" would have taken a lot longer than I had the patience or time for to clean it up.

Hey @Trav you remember this car?
View attachment 29071

Sure do from when I did the transmission repair on it. That was terrible under the cover, I wont use dino in anything I own and have not for over 30 years. No engine I have owned since new had varnish or sludge even the so called problem engines (VW 1.8T, ecotec 2.0T) stayed new looking clean.
Good oil, no snake oils, and above all no extended OCI.

Varnish acts like a primer for sludge and contaminates, it can also gum up sensitive precicion parts like cam phasers, hydraulic tensioners, spool valves (a common Honda issue), cylinder acuation components, piston rings, cam chain pin wear, etc. You dont want varnish in any of these parts, it can be a precursor to much greater and very expensive issues in the future. Oil is cheap repairs of this nature are not.

 

[OVERKILL]

Just looked up the Owner Manual and Scheduled maintenance manuals from Ford. Here is a couple things that I found that give no excuse to Amsoil for that amount of varnish:
- "Synthetic or synthetic blends are not mandatory"
- Recommended OCI is 5k miles with a 5w30 conventional, so even a "simple" Amsoil XL shouldn't have had any issues going an extra couple thousand miles per OCI.

So returning to the original topic of this thread - I think varnish will happen either way, conventional for 5k or synthetic for 10k, unless you pick an oil that is known to pack a punch when it comes to cleaning. Pennzoil Ultra Platinum or Mobil1 0w40 come to mind. Also a small engine in a large engine bay may get less varnish due to less heat under the hood. Vice versa - a large engine in a tight engine bay won't get cooled as well, so will probably end up with more varnish regardless of oil used.

Quick shot of my old E39 M5 through the fill hole which I think would meet your tight engine bay, physically large engine criteria. I have no idea was the previous owner ran, this was M1 0w-40: