Why does synthetic oil turn black faster?

[Spade]

I'm not sure about this, but it seems that mineral oil doesn't turn black faster than synthetic oil.... I've been using these 2 types for years now and realise that synthetic becomes black faster? anyone have any idea?

[Darth_mel]

If it's turning black faster means the oil is doing it's job well mah.

 

It's a good thing to see IMO.

[Octopus]

Could be better cleaning ability, could be due to additives in the synthetic oil. Read somewhere that certain lube oil due to its additives, will turn dark colour as it gets heated up.

[Lwteyu]

hi

Need advise from fellow car owner.

Going for 1000 km servcing soon,

Change engine oil hyundai carmanual recommend SAE 5W-20/30.(even have Shell Helix printed)

Any idea where can get cheaper SAE 5W-20 4 litre?

 

The petrol station at shell sell 5W-40 helix ultra 4l at $89.80., Esso 5w-40 at $86.60....hmmmm. anyone got better cheaper lobang?(dun tell me go Malaysia lah)

 

Anyway mine is a hyundai verna 1.4a.

 

thanks for the advise

[Apollo]

synthetic oil hv detergent additives to help remove sludge and others. mineral oil produces sludge.

[Genie47]

Mineral oil is sludge provided it gets cooked long enough. Today's mineral oil not like the poor quality stuff our fathers used. Sufficient for city use but if chiong NSH, better don't.

[Genie47]

Use the Search Luke......

[Darth_mel]

Can try cxxxxxe 5W40 full synthetic. Using it now for the 2nd time.

 

Only $38.90 and comes with free car shampoo some more. Just bought mine at Autobacs.

 

But if you really want super cheap, cheap can try Sakura oil at Mustafa Shopping Centre. Only $17.50 for 4L. But I doubt so lah.....

Edited February 15, 2006 by Darth_mel

[Mits_jc]

if u want cheaper shell/mobil, can try searching "engine oil" on sg yahoo auctions or sg ebay.

 

if not, get can cheaper oils which are equally juz as good or even better than shell/mobil.

[Nutty]

Bro, check Yahoo auction.

 

Ppl are selling Helix at $54 $54... sometimes even $50

[Tkseah]

U can find the Shell at $54 here..

 

http://clubhyundai.org/forums/viewtopic.php?t=23165

 

But u may also wanna consider cheaper alternatives..

[Octopus]

I'm not sure about this, but it seems that mineral oil doesn't turn black faster than synthetic oil.... I've been using these 2 types for years now and realise that synthetic becomes black faster? anyone have any idea?

 

Check out this link: http://theoildrop.server101.com/ubb/ultima...ic;f=1;t=014088

 

Its about a guy who experiment on heating up some engine oil to determine different brand of engine oil turns dark due to heat, and Mobil 1 is one of them.

[Spade]

wow thanks bro, and pple!

 

taken off the site from JAG :

 

I see this question brought up all of the time and want to put it to rest. Stated more accurately, the reason that Mobil 1 darkens more so than many other motor oils in an engine is because it darkens more than many others just from being heated to operating temperatures. It is not because it's doing a better job of cleaning like most assume; it does clean well as do many other quality oils but that's not why it gets darker in use than some other oils in same engine use. Put in even simpler terms, it changes color a lot when heated.

 

And while we're on the topic, Redline oil gets even darker when heated than Mobil 1, given high enough temperatures. Not that it matters; it's just an FYI. Another FYI: Castrol 5W-40, 10W-40, and Gold GC stay very much the same color as they started when heated. I have same info on some other oils but that wasn't the point of this thread, so I'll end here.

 

Color change is a function of several things: additive package darkening, oxidation of basestocks (bad), and amount of carbon in the oil. For Mobil 1 and Redline, additive package darkening happens easily and well before the basestocks have darkened from oxidation.

 

How do I know? I heated the oils to many temperatures for many lengths of time. How else would I know?

 

Well it's tough to say because it is temperature AND time dependent. One extreme example is that I was able to turn most synthetics very black in 30-60 seconds if I had them at over 600F degrees.

Mobil 1 5W-30 and 10W-30 did darken noticeably when at 300F degrees for several hours, while the Castrol Syntecs I tested barely changed color. In an engine, the oil may never get over 220F degrees, but it's in use for MANY MANY hours, so it's enough to darken the oil just from heat.

 

To determine if an oil needs an oil cooler would be much better done by at best measuring the oil temp or at worst using a pyrometer on the oil pan. There are so many variables involved in the color change of used motor oil that going by that is shakey ground to stand on. Some conclusions can be made however. I know that for example GC's color is less affected by heat than Mobil 1 5W-30, so if one engine is making GC very dark compared to another engine using M1, the engine using GC is either running longer intervals, getting more blowby (carbon) into the oil, or it's running HOT AS HECK (>300F likely). GC takes such high temps to change color that no healthy engine will get the oil hot enough to change it just from heat.

 

The M1 might darken up, but the conventional will break down and tar up first, usually much sooner. The same can be said for some of the older Syntec formulae.

 

I don't care about any oil changing color once in service. It indicates absolutely nothing concerning the essential properties of the lubricant. It certainly isn't probative to thermal oxidation and breakdown. And other than when I put it in and drain it out, I don't stare at the color all that much. It just isn't that much of an automotive fashion accessory. Maybe if I had a leaker, I'd feel differently and try to find an oil that better complimented my block paint.

 

No I didn't test Pennzoil Platinum but did test the older Pennzoil 10W-30 Synthetic (API SL) about 2 years ago. I think it had the name "Penzane" or "Pentane" in it's ad literature. I don't want to discuss the results because the Platinum could be much better than the old Pennzoil synthetic.

 

Alright fellas, apparently my attempt at giving only a small portion of my OCD-inspired oil testing has opened pandora's box and spread from the color change topic to oxidative stability and the other things that really matter. It sounds like there is a desire for more data. I do not have enough spare time on my hands to present all of the results from several years of testing, but you may look at the list of oils tested below and ask any questions you have.

 

The purpose of the testing was to evaluate how the oils reacted to high temperatures. Whatever could be observed was and was recorded but the main focus was on (1) viscosity change resulting from the opposing effects of oxidation and break-up of viscosity index improvers, (2) flash point, (3) deposit formation, (4) volatility. The color and odor was noted but not used in any judging except when the odor indicated oxidation had occured. I did these on my own time out of scientific curiosity. I was not being paid by anyone.

 

Mobil 1 5W-30 EP (SL)

Mobil 1 10W-30 (SL)

Mobil 1 0W-40 (SL)

Castrol Syntec 5W-40 (SL)

Castrol Syntec 10W-40 (SM)

Gold German Castrol (SL)

Valvoline Synpower 10W-30 (SL)

Valvoline Synpower 5W-40 (SL)

Amsoil 5W-40 (SL)

Pennzoil Synthetic 10W-30 (SL)

SAE 30HD weight Pennzoil dino oil (SJ)

Redline 5W-30 (bought in 2002/2003 so ?)