Does synthetic clean better than conventional

[JOD]

Originally Posted By: demarpaint
Originally Posted By: dparm


Modern API SN oils clean very well, even in conventional form.


I wish that was the case for my 2000 Century having religious 3K Dino OC's its entire life including the new SN conventional oils. The valve train was far from clean after 85K miles when I took it from my father. It took me a lot more than oil to clean it up. Next OC I will be changing over to Havoline Synthetic and see if that does any additional cleaning.


Your 2000 Century didn't spend most of its life on SN-rated oils. There's a pretty significant difference between the SJ-rated oils and oils today. Deposit control requirements have increased, significantly.

 

[Pajero]

Well I have been doing some research and compared the oils listed on the PQIA. According to PQIA, AMSOIL Signature Series has 3681 Calcium, which was one of the highest. I'm only a novice looking at the numbers. Eneos Sustina has good numbers. Scroll down for Eneos Sustina used oil analysis

I know there are a plethora of factors to consider.

Ultra is highly regarded on the threads for its cleaning abilities. Just a layman's opinion.

Disclamier: I don't sell Amsoil. Aforementioned oil are a bit $$$$$ Good luck sir!

Pajero

 

[TrevorS]

Originally Posted By: demarpaint
My father was the original owner and the car, I have every invoice for the services and the miles logged. The oil was changed like clockwork every 3K miles [with conventional oil], most of which was done by the dealer, some Avis Lube, and a local shop. So neglect/abuse is out of the question. There are no mechanical issues what so ever with the engine. Is the 3.1L engine a sludge monster? Was the severe service user profile the car was used under the issue? Or did Conventional Oil changed every 3K not live up to the task? I don't know. What I do know is the car was properly maintained, over kill many would say.


Is there any chance that the dealer didn't actually do the oil changes?

 

[demarpaint]

Originally Posted By: JOD
Originally Posted By: demarpaint
Originally Posted By: dparm


Modern API SN oils clean very well, even in conventional form.


I wish that was the case for my 2000 Century having religious 3K Dino OC's its entire life including the new SN conventional oils. The valve train was far from clean after 85K miles when I took it from my father. It took me a lot more than oil to clean it up. Next OC I will be changing over to Havoline Synthetic and see if that does any additional cleaning.


Your 2000 Century didn't spend most of its life on SN-rated oils. There's a pretty significant difference between the SJ-rated oils and oils today. Deposit control requirements have increased, significantly.


SM was good oil, touted as good cleaning oil here too, SL was no slouch either. They were used for years in that car, and did no cleaning of the mess the older formulations left. Now we're what, about 2+ years into SN oil, that did nothing to clean up the mess either.

I state my Buick example for those members who think good conventional oil can clean up an engine, it dropped the ball in my Buick.

 

[badtlc]

Originally Posted By: dparm
Originally Posted By: badtlc
To be fair, I don't think there has been anything posted on this site that shows oil by itself has any cleaning abilities, just some oils are better at keeping things clean than others.


Sure there has. There have been threads where people showed before and after photos of neglected engines (missed oil changes, low oil level, very lousy filter).

Modern API SN oils clean very well, even in conventional form.


Would you share some? I have been on this site for a long time. I haven't seen any or been able to find any.

Thanks.

 

[JOD]

I don't want to discount your experience-it is what it is, after all. That said, I have to wonder is something else is going on, such as the infamous 3100 gasket issue causing the sludge/buildup, or the shop(s) using a cheap bulk oil that doesn't actually meet the API specs it claims to meet. Even under the most harsh short-trip conditions, your case is highly unusual.

There are reasons why a synthetic oil can be more likely to resist oxidation, but in terms of cleaning deposits that are already there, that's mainly a function of the detergent additives used. I don't see how a synthetic oil is really going to help any more than a conventional oil in your situation.

 

[TrevorS]

Originally Posted By: demarpaint
SM was good oil, touted as good cleaning oil here too, SL was no slouch either. They were used for years in that car, and did no cleaning of the mess the older formulations left. Now we're what, about 2+ years into SN oil, that did nothing to clean up the mess either.

I state my Buick example for those members who think good conventional oil can clean up an engine, it dropped the ball in my Buick.


Don't get me wrong, I think synthetics are better and run them myself, but we have no way of knowing whether the results, either causing the heavy varnish in the first place or not cleaning would have been different with semi syn or synthetic oil.

We don't exactly know what quality of conventional was being put into your vehicle either.

And has the conventional caused a mechanical issue or simply a cosmetic issue?

As JOD said, a quality SN conventional might perform similar to synthetic if you were to go through this again. As they say, past performance is not an indicator of future results. Way too many variables.

 

[bigt61]

Originally Posted By: demarpaint
Originally Posted By: dparm


The question would be, is that engine prone to sludge due to a design flaw, or did it just develop sludge from neglect/abuse?


My father was the original owner and the car, I have every invoice for the services and the miles logged. The oil was changed like clockwork every 3K miles [with conventional oil], most of which was done by the dealer, some Avis Lube, and a local shop. So neglect/abuse is out of the question. There are no mechanical issues what so ever with the engine. Is the 3.1L engine a sludge monster? Was the severe service user profile the car was used under the issue? Or did Conventional Oil changed every 3K not live up to the task? I don't know. What I do know is the car was properly maintained, over kill many would say.


Did your Dad ever check the oil level between changes? Is it possible that it was leaking or burning oil and that by the 3000 mile mark it was running a few quarts low? This would contribute to sludging. I had a 92 Lumina with the 3.1L at one point and it ran well at 190k when I sold it, even though it rattled a bit at cold start up. IIRC it didn't look bad through the fill hole but I always ran 20W-50 back then - I had a big stash of it.

 

[demarpaint]

Originally Posted By: bigt61


Did your Dad ever check the oil level between changes? Is it possible that it was leaking or burning oil and that by the 3000 mile mark it was running a few quarts low? This would contribute to sludging. I had a 92 Lumina with the 3.1L at one point and it ran well at 190k when I sold it, even though it rattled a bit at cold start up. IIRC it didn't look bad through the fill hole but I always ran 20W-50 back then - I had a big stash of it.


The car was very well maintained, it doesn't burn or leak a drop of oil. My father is not a DIY guy but he does religiously check fluids, the oil level is/was always full. Keep in mind the OCI's were only 3K and the oil always remained full. It has no coolant leaks, never overheated or left anyone stranded. The only problem was a CEL light for a small EVAP emissions system leak, which was corrected by replacing a fuel tank pressure sensor. It had the P1811 transmission code which Trav and I corrected by installing an accumulator kit. Neither of the two issues would have any impact on sludge or varnish, they recently occurred and were corrected almost immediately.

 

[demarpaint]

A few good questions have been brought up. There are no mechanical issues with the engine, no coolant leaks or head gasket issues, what you see is all cosmetic. The car had a combo of Mobil, Kendall, or Pennzoil products, all conventional.

As far as older oil being used back in the early years not being as good as the oils of today, there is no disputing that. However probably close to 30,000 miles of the ~97,000 miles the car had API SN oil, prior to that SM and SL oil. If the conventional SN oil had such great cleaning ability what happened? It had about 30K miles to work. It took my dosing it with a cleaner to start seeing an improvement. I have no idea how synthetic oil would have done, but I do know how SN conventional oil did.

I'm toying around with seeing how well Havoline Synthetic oil does going forward since I bought enough for 2 years worth of oil changes. My point in all of this discussion is telling someone run Pennzoil conventional for x amount of miles and it will clean up an engine, isn't always the case. Now I plan on seeing if the same holds true for synthetic oil.

 

[wag123]

Have the PCV valve and the rest of the PCV system been checked for proper function on this car?

 

[tig1]

YES!!

 

[KCJeep]

Originally Posted By: demarpaint
My point in all of this discussion is telling someone run Pennzoil conventional for x amount of miles and it will clean up an engine, isn't always the case.


Yes a common comment on here... oh the power of marketing! I like Pennzoil conventional but I haven't found it, or any other oil I've tried yet, to be a cleaning Genie in a bottle.

 

[demarpaint]

Originally Posted By: wag123
Have the PCV valve and the rest of the PCV system been checked for proper function on this car?


Yes

 

[TrevorS]

I think sludge removal will differ based on the reason it happened.

If it happened because prior oil was poor or was left in too long, then detergents in new quality oil will reach those areas in enough quantity and begin the cleanup. If the sludge or coking has been there for years and years, it will be harder.

If however the sludge or coking is due to engine design, eg areas that don't get splashed a lot, areas where oil can pool, areas that have thermal issues, then new oil is under the same challenging conditions as it has always been and will struggle to clean.

My engines are spotless through the fill hole and have always run quality synthetic at short intervals. Under the fill hole in one of them however, there is a bolt head quite high up that is slightly concave. Oil just sits there on the bolt head itself and the surrounding area. I can imagine that oil splashes up there and fills up this concave space, but new oil will always sit on top of old oil or displaces it too slowly.

Consequently, there is gritty carbon in the concave part of the bolt head. It isn't getting any better and I am running one weight heavier than recommended and quality synthetics. It has appeared despite continuous use of quality synthetics with short oci's and is not going away.

Now that I mention it, I'm going to reach in with a paper towel around a screwdriver and see what I can remove. It's kind of bothering me!

 

[Hyde244]

Use either - just start with a shorter OCI when trying to clean on engine.

 

[TrevorS]

Originally Posted By: TrevorS
I think sludge removal will differ based on the reason it happened.

If it happened because prior oil was poor or was left in too long, then detergents in new quality oil will reach those areas in enough quantity and begin the cleanup. If the sludge or coking has been there for years and years, it will be harder.

If however the sludge or coking is due to engine design, eg areas that don't get splashed a lot, areas where oil can pool, areas that have thermal issues, then new oil is under the same challenging conditions as it has always been and will struggle to clean.

My engines are spotless through the fill hole and have always run quality synthetic at short intervals. Under the fill hole in one of them however, there is a bolt head quite high up that is slightly concave. Oil just sits there on the bolt head itself and the surrounding area. I can imagine that oil splashes up there and fills up this concave space, but new oil will always sit on top of old oil or displaces it too slowly.

Consequently, there is gritty carbon in the concave part of the bolt head. It isn't getting any better and I am running one weight heavier than recommended and quality synthetics. It has appeared despite continuous use of quality synthetics with short oci's and is not going away.

Now that I mention it, I'm going to reach in with a paper towel around a screwdriver and see what I can remove. It's kind of bothering me!


Just managed to easily clean the areas where grit had built up. This was just through the fill hole so no doubt there are other similar bolts and surrounding areas with small build up.

It obviously hasn't harmed anything. Be interesting to see if this grit builds up again as I now do longer oci's, still with full syn.

 

[wally6934]

Originally Posted By: TrevorS
I think sludge removal will differ based on the reason it happened.

If it happened because prior oil was poor or was left in too long, then detergents in new quality oil will reach those areas in enough quantity and begin the cleanup. If the sludge or coking has been there for years and years, it will be harder.

If however the sludge or coking is due to engine design, eg areas that don't get splashed a lot, areas where oil can pool, areas that have thermal issues, then new oil is under the same challenging conditions as it has always been and will struggle to clean.


Good point. I was mainly thinking neglect with my OP but there are various reasons for getting sludge.

 

[F350]

Originally Posted By: demarpaint
I state my Buick example for those members who think good conventional oil can clean up an engine, it dropped the ball in my Buick.


Yeah, yeah, it was maintained religiously. But like everyone else, you never told us how he used the car while he had it. So, how did he?

 

[demarpaint]

Originally Posted By: F350
Originally Posted By: demarpaint
I state my Buick example for those members who think good conventional oil can clean up an engine, it dropped the ball in my Buick.


Yeah, yeah, it was maintained religiously. But like everyone else, you never told us how he used the car while he had it. So, how did he?


I told how the car was used in the link with the pictures, typical Long Island, NY use. That falls into the severe service category, which IMO most cars do. 3K conventional OCI's in case you missed that.