Discussion: Engine oils

AVANTE · November 20, 2020

Hi guys, hope you're all doing well.

I've been having doubts about engine oils in the lankan context and have been doing alot of reading recently. There are still somethings I want to learn more about and need clarification on.

1) Modern engine oils can go longer than ever, so why are people still changing at the ancient 5000km mark? My service records state that the next oil change should happen at 5k (Mobil Semi-Synthetic 10W40) and I have seen many people with modern cars do the same.

2) Is it true that SAE 40/50 rated oils are better for higher mileage engines to secure the loose gaps/tolerances?

3) Liqui Moly vs Mobil. Who truly is the pioneer in modern oil tech? Pricey stuff but who has the edge? I have read alot of cases in forums where they swear Mobil oils are special and different from other brands in their sludge clearing properties. I have also seen people spitting at Liqui Moly saying "eww".

4) Also, a small side topic. Engine flushing: Diesel vs purpose engineered flushes. People say flushes/additives can hurt the oil pump on old engines and some swear by diesel. But there are also people saying diesels leave stains behind.

What do you guys think? Would like to hear your opinions on these.

Edited November 20, 2020 by AVANTE

iRage · November 20, 2020

1. Well...according to the oil manufacturers themselves most of the mineral ones come with a recommended change interval of 5-6k...synthetics 7-8k and synthetics 10-12k....then again depending on the manufacturer the semi and fully synthetics can go up. More than the car..I believe the determining factor would be the oil itself (and then how you use the car).

2. Again at the end of the day it is about the state of the engine as well...if the engine is in good condition with proper compression, etc...then you really do not need an oil to fill the gaps/tolerances. The thicker oil is a must for old engines is something that comes from the "good old" days and the reality is engines do wear and tear and subsequently will need oils to compensate. The other side of the belief from the good old days is that as the car gets older the cooling system might be inefficient...thus a heavier oil will absorb more heat and slightly compensate for any loss of efficiency in the cooling system.

3. I believe both Mobil and LM make good oils...but they are not common in SL due to the cost factor. Have not used Mobil oils in SL..but did use LM on the Mark X. I do not think that the additives did any regenerating of the walls or anything of the sort...but it did do a good job on extremely long runs than the Toyota oil did with the same weight 10W-30 which later got swapped for 40.

4. Flushes....there is truth to that. Had it happen to a friend's Ford Escort during my college days (we spent thanks giving holidays changing oil seals)...old cars can have work out rings, seals and other small components. On one hand the flush it self can cause these old parts to degenerate and loosen up or brake creating an outlet for oils to pour out. Secondly, the oils do create sort of a membrane with time that sort of....not plugs up leaks but slows it down to slight seepages that might go unnoticed. The flush can clear out this membrane and now the location of the seepage shows a proper fluid leak.

AVANTE · November 20, 2020

17 minutes ago, iRage said:

1. Well...according to the oil manufacturers themselves most of the mineral ones come with a recommended change interval of 5-6k...synthetics 7-8k and synthetics 10-12k....then again depending on the manufacturer the semi and fully synthetics can go up. More than the car..I believe the determining factor would be the oil itself (and then how you use the car).

True true. People need to be informed on early oil changes, they're just a waste of money. It's okay if the oil is more than an year old, but if not it's just pointless. Why spend extra for semi-synthetic when you change it at 5k like mineral oil right?

20 minutes ago, iRage said:

2. Again at the end of the day it is about the state of the engine as well...if the engine is in good condition with proper compression, etc...then you really do not need an oil to fill the gaps/tolerances. The thicker oil is a must for old engines is something that comes from the "good old" days and the reality is engines do wear and tear and subsequently will need oils to compensate. The other side of the belief from the good old days is that as the car gets older the cooling system might be inefficient...thus a heavier oil will absorb more heat and slightly compensate for any loss of efficiency in the cooling system.

Agreed.

22 minutes ago, iRage said:

3. I believe both Mobil and LM make good oils...but they are not common in SL due to the cost factor. Have not used Mobil oils in SL..but did use LM on the Mark X. I do not think that the additives did any regenerating of the walls or anything of the sort...but it did do a good job on extremely long runs than the Toyota oil did with the same weight 10W-30 which later got swapped for 40.

4. Flushes....there is truth to that. Had it happen to a friend's Ford Escort during my college days (we spent thanks giving holidays changing oil seals)...old cars can have work out rings, seals and other small components. On one hand the flush it self can cause these old parts to degenerate and loosen up or brake creating an outlet for oils to pour out. Secondly, the oils do create sort of a membrane with time that sort of....not plugs up leaks but slows it down to slight seepages that might go unnoticed. The flush can clear out this membrane and now the location of the seepage shows a proper fluid leak.

So LM vs Mobil is a topic of personal preference. I use Mobil for both car and motorbikes and it's just one of those knock on wood brands you just can't go wrong with.

Wow that escort must have been fun.😅 There's another topic on how some people say not to clean the engine too much (tune up) and get rid of all the carbon deposits as some of it is needed for the valves to seal a bit more appropriately. Another guy said his diesel golf smoked to death after adding flush and additives. Horror stories are out there. I guess the verdict is don't use flushes for really old engines? Better to just dismantle and clean or maybe rebuild/replace.

On a serious note, what say you about flushing with diesel? There are people who will vouch for diesel as well as say No. It seems to be another experience/preference based debate but there are surely some solid facts right?

Kavvz · November 22, 2020

On 11/20/2020 at 9:32 AM, AVANTE said:

3) Liqui Moly vs Mobil. Who truly is the pioneer in modern oil tech? Pricey stuff but who has the edge? I have read alot of cases in forums where they swear Mobil oils are special and different from other brands in their sludge clearing properties. I have also seen people spitting at Liqui Moly saying "eww".

Can't comment on the other stuff (no real experience with Liqui Molly) But I do use Mobil off and on, mainly as their marketing is so strong, but most of the time (70-80% of the time I would say) I use Castrol Edge fully synthetic. Its cheaper, and gets the job done. I've used it on a diesel and various other petrol cars for 3-5 years and I don't really see a huge difference between Mobil f.synthetic and Castrol f.synthetic to be honest.

AVANTE · November 22, 2020

1 hour ago, Kavvz said:

Can't comment on the other stuff (no real experience with Liqui Molly) But I do use Mobil off and on, mainly as their marketing is so strong, but most of the time (70-80% of the time I would say) I use Castrol Edge fully synthetic. Its cheaper, and gets the job done. I've used it on a diesel and various other petrol cars for 3-5 years and I don't really see a huge difference between Mobil f.synthetic and Castrol f.synthetic to be honest.

So what I can conclude from all this is, you just can't go wrong with any of the top brands.

BMW used repackaged Castrol (now Shell)

Peugeot/Citroen goes with Total

Mercedes Benz stands with Mobil

GM also go with ExxonMobil brands.

Also I got another question, since W rating doesn't matter in lanka, I won't be facing any issue in going from 10W-40 to something like 5W-40 right?

Kavvz · November 22, 2020

10 hours ago, AVANTE said:

Also I got another question, since W rating doesn't matter in lanka, I won't be facing any issue in going from 10W-40 to something like 5W-40 right?

Yes: No issue at all for our Sri Lankan climate. All good 👍

Kavvz · January 6, 2021

Hello Gentlemen: I was wondering whether any of you may have a suggestion for any products that I could use to help flush out sludge etc. before an oil change?

(Background: I recently purchased an older car that may not have had its oil changes on time and while there are no issues at this point I do want to address any potential engine sludge issues as its an older car running (what I believe to be) regular mineral oil. I figure adding some engine oil additives before the next oil change is probably a good idea. Does anyone have any preferred brands that I could look into for this? )

I understand Liqui-Moly and Wurth both have good products for the above. Has anyone used either one or is there any other brand you can give a recommendation for ?

Thanks in advance.

Ruslan · January 7, 2021

5 hours ago, Kavvz said:

Hello Gentlemen: I was wondering whether any of you may have a suggestion for any products that I could use to help flush out sludge etc. before an oil change?

(Background: I recently purchased an older car that may not have had its oil changes on time and while there are no issues at this point I do want to address any potential engine sludge issues as its an older car running (what I believe to be) regular mineral oil. I figure adding some engine oil additives before the next oil change is probably a good idea. Does anyone have any preferred brands that I could look into for this? )

I understand Liqui-Moly and Wurth both have good products for the above. Has anyone used either one or is there any other brand you can give a recommendation for ?

Thanks in advance.

Haven’t use both above but BG 109 (EPR as they say now). Had good results with Vios 2006. Well its not heavily sludged in the first place and has removed the Yellowish varnish under the tappet cover. When changing the oil, oil has turned into darkened brown. After the oil change oil stayed yellow to dark yellow till 5k mark. Not sure how it will behave on highly sludged engine. So beware. Heard these are bad for valve stem seals. But in my case havent noticed any oil burn after use.

Edited January 7, 2021 by Ruslan

MaleCortana · January 7, 2021

My mechanic claimed that he had a surge of cars that used LiquiMoly and somehow the engines had to be replaced or something like that, but take it with a lot of salt as I have no personal experience anyway.

AFAIK people say that you shouldn't do flushes (that is using the machine that pumps stuff) on older engines as worn bits and pieces can come loose.

Kavvz · January 9, 2021

On 1/6/2021 at 9:49 PM, Ruslan said:

So beware. Heard these are bad for valve stem seals. But in my case havent noticed any oil burn after use.

On 1/7/2021 at 3:36 AM, MaleCortana said:

My mechanic claimed that he had a surge of cars that used LiquiMoly and somehow the engines had to be replaced or something like that, but take it with a lot of salt as I have no personal experience anyway.

Thanks for your input Gentleman: Upon further research as well as taking into consideration your comments above I've decided to just drain out the old oil and simply switch to synthetic oil and not add any additives or any flushing chemicals as the risks seem to greatly outweigh the benefits.

CNX · January 11, 2021

Good decision. Just make sure you do the first oil change after switching a bit sooner may be around 3K km to get rid of any nasties that get transferred to the synthetic oil.

Edited January 11, 2021 by CNX