TGMO 0W-20 SN, TBN/TAN, 5286 M, 85 Corolla 4A-LC

[Gokhan]

This is my third UOA with Toyota (TGMO) 0W-20 SN/GF-5 made in US by ExxonMobil.

The OCI duration is 5286 miles, 506 days. No makeup oil was added and the oil consumption was minimal -- about 0.3 - 0.4 quarts over the OCI (similar to last OCI) and probably mostly due to a small leak at the oil pan. Almost no oil consumption is thanks to replacing my valve-stem oil seals. Oil-change capacity is 3.5 quarts with oil-filter change. Dry-fill capacity is 3.9 quarts. The filter used is Toyota 90915-YZZF2. Cumulative miles and age on the 1.6-liter carbureted SOHC engine at the time of the UOA sample is 260480 miles, ~ 30 years. In addition to some high-speed freeway driving, the car mostly saw a lot of short trips that you would think would be hard on the oil. Temperatures in the area were mild, warm, or hot during last year.

I used the $30 (shipping included) high-quality aluminum Blackstone vacuum pump for oil sampling and it worked wonderfully. It's clean, fast, accurate, and lets you have a UOA oil before you change the oil so that you can use a different oil next time if you aren't satisfied. I strongly recommend it to everyone over the messy drain-hole method -- it's much, much, much better. Note that the pump doesn't touch the oil and doesn't require cleaning.

Note that the TBN and TAN are 4.68 and 3.54. My rule of thumb is that the TBN needs to stay larger than the TAN over the OCI for optimal protection. Note that the TBN value by WearCheck is the true TBN using the modern test method. Blackstone TBN values are underestimated.

Silicon is very impressive: 12 ppm vs. the 11 ppm of the virgin oil -- almost no dust is entering the engine, thanks to my meticulous seating of the air-filter gaskets over the carburetor.

Note that the viscosity at 9.55 cSt is very high for a 0W-20. I am guessing this to be due to some antifreeze contamination. There is 43 ppm sodium (Na) in the UOA signaling antifreeze contamination. However, they didn't find any glycol in the IR test. Go figure.

These are my previous UOAs, TGMO 0W-20 SN @ 249035 miles and PYB 5W-20 SN @ 243729 miles:

Previous Blackstone UOAs

Here is the official VOA of TGMO 0W-20 SN virgin oil

I am going to use ACDelco cooling-system seal tabs (part no. 10-108), hoping that it will stop my coolant seep. It seems to be happening through some holes in the aluminum cylinder head.

Note that this time the driving conditions were worse with a lot of short trips. Also, I broke the 1-year-maximum-OCI rule (!!) and waited for 506 days before I sampled for the UOA since my mileage was still low. These probably contributed to worse wear-metal results on the lead, aluminum, and chromium this time. I think I will give the thick oil a try next time (in my oil change this or next weekend) and run Mobil 1 0W-40 SN. What do you guys think?

 

[lubricatosaurus]

Report back when the engine is broken in.

 

[Nate1979]

Originally Posted By: lubricatosaurus
Report back when the engine is broken in.

LOL

 

[Garak]

Looks like you could have gone further, but you went a good length of time, and are cognizant of the possibility of coolant ingress. And yes, your silicon is quite low.

 

[Pontual]

Could be 43ppm of ingested Californian beach marine salt?

 

[Benito]

Originally Posted By: Gokhan
Note that the TBN value by WearCheck is the true TBN using the modern test method. Blackstone TBN values are underestimated.


Blackstone uses ASTM D-4739 which is the preferred method for used oil.

ASTM D-2896 is used for virgin oil and should only be used for used oil when a comparison to virgin TBN is desired.

On used oil, ASTM D-4739 will give a lower number. ASTM D-2896 will give a higher number. This can be misleading as to the true condition of the oil and lead to over extended oci's.

Which method are you saying Wearcheck is using? One of these or FTIR?

 

[BigD1]

Bar's Leak tablets are the same as the ACDelco tablets, and they are cheaper, and you get one more per pack too. NAPA and O'Reilly's auto parts stock them.

http://barsleaks.com/product/radiator-stop-leak-tablets/

 

[JerryBob]

I sold my 85 Corolla with the 4-AC engine only 4 years ago. Great car. Even Toyota themselves don't make them like that anymore.

The only problem I had was the clutch master cylinder would go out every couple of years. Must have been a poor design.

 

[camrydriver111]

It's interesting they report metals to 0.1 ppm. I didn't know AA was that accurate. I personally have a hard time believing they could distinguish between Cr 5.5 and 5.6 although I could be wrong since new instruments are coming out all the time.

The car seems to be OK with 0W20 as well.

 

[Gokhan]

Originally Posted By: Nate1979
Originally Posted By: lubricatosaurus
Report back when the engine is broken in.

LOL

Originally Posted By: JerryBob
I sold my 85 Corolla with the 4-AC engine only 4 years ago. Great car. Even Toyota themselves don't make them like that anymore.

The only problem I had was the clutch master cylinder would go out every couple of years. Must have been a poor design.

I don't think I will ever be able to break in this engine. It still performs as good as new -- no oil consumption, gas mileage similar to newer Corollas.

Mine is a 4-speed AT -- the proven Aisin-Warner A240L transmission that still runs like clockwork.

Regarding the clutch master cylinder issue, it's probably because the aftermarket rebuilt ones you were putting use low-quality parts or are rebuilt poorly. I rebuilt my brake master cylinder using an OEM kit once and it hasn't leaked a drop since. I was really impressed by the quality of the machining work on the core. It was flawless machining. Again, I am guessing in your case the mistake was to use aftermarket gaskets and seals during rebuilt. I don't think you can find any better machined parts then they did in Japan in the 1980s.

 

[Gokhan]

Originally Posted By: Pontual
Could be 43ppm of ingested Californian beach marine salt?

I thought about it myself. However, the car is parked 4.73 miles from Venice Beach; although, I go there almost every weekend. 43 ppm Na is about 135 mg in 3.9 qt of 0W-20 oil, which is contained in about 343 mg of salt, and I doubt that much salt could get into the oil from the air that easily.

Also, something needs to explain the oil thickening. Perhaps, since it's an old-engine design, it tends to thicken the oil -- I don't know.

 

[Gokhan]

Originally Posted By: Benito
Originally Posted By: Gokhan
Note that the TBN value by WearCheck is the true TBN using the modern test method. Blackstone TBN values are underestimated.


Blackstone uses ASTM D-4739 which is the preferred method for used oil.

ASTM D-2896 is used for virgin oil and should only be used for used oil when a comparison to virgin TBN is desired.

On used oil, ASTM D-4739 will give a lower number. ASTM D-2896 will give a higher number. This can be misleading as to the true condition of the oil and lead to over extended oci's.

Which method are you saying Wearcheck is using? One of these or FTIR?

I think you're right. ASTM gives a lot of info:

http://compass.astm.org/EDIT/html_annot.cgi?D4739

Here is an excerpt:

5 | Significance and Use

5.1 New and used petroleum products can contain basic constituents that are present as additives. The relative amount of these materials can be determined by titration with acids. The base number is a measure of the amount of basic substances in the oil always under the conditions of the test. It is sometimes used as a measure of lubricant degradation in service. However, any condemning limit shall be empirically established.

5.2 As stated in 1.2, this test method uses a weaker acid to titrate the base than Test Method D2896, and the titration solvents are also different. Test Method D2896 uses a stronger acid and a more polar solvent system than Test Method D4739. As a result, Test Method D2896 will titrate salts of weak acids (soaps), basic salts of polyacidic bases, and weak alkaline salts of some metals. They do not protect the oil from acidic components due to the degradation of the oil. This test method may produce a falsely exaggerated base number. Test Method D4739 will probably not titrate these weak bases but, if so, will titrate them to a lesser degree of completion. It measures only the basic components of the additive package that neutralizes acids. On the other hand, if the additive package contains weak basic components that do not play a role in neutralizing the acidic components of the degrading oil, then the Test Method D4739 result may be falsely understated.

5.3 Particular care is required in the interpretation of the base number of new and used lubricants.

5.3.1 When the base number of the new oil is required as an expression of its manufactured quality, Test Method D2896 is preferred, since it is known to titrate weak bases that this test method may or may not titrate reliably.

5.3.2 When the base number of in-service or at-term oil is required, this test method is preferred because in many cases, especially for internal combustion engine oils, weakly basic degradation products are possible. Test Method D2896 will titrate these, thus giving a false value of essential basicity. This test method may or may not titrate these weak acids.

5.3.3 When the loss of base number value, as the oils proceed in service, is the consideration, this test method is to be preferred and all values including the unused oil shall be determined by this test method. Base numbers obtained by this test method shall not be related to base numbers obtained by another test method such as Test Method D2896.

5.3.4 In ASTM Interlaboratory Crosscheck Programs for both new and used lubricants, historically Test Method D2896 gives a higher value for base number.

I think no matter which method is used, you need to be careful in interpreting the numbers. One good thing about WearCheck is that they also give the TAN value, which is also critical. It looks like the difference between TBN and TAN is more appropriate in judging the oil condition than the TBN alone.

WearCheck also provides oxidation, nitration, and sulfation, which are useful in judging the oil condition as well.

There was also some discussion about this here on BITOG. The Oronite article references there is pretty good in discussing TBN and TAN:

TBN, TAN, Ca, Mg, base-oil quality, oil life

FTIR (Fourier transform infrared) spectroscopy WearCheck uses is for looking at soot, oxidation, sulfation, nitration, glycol, etc. (light-green rows in the UOA posted above). It needs to have the virgin oil as the baseline reference to make any sense. I did provide them with a virgin sample last year.

 

[Gokhan]

Originally Posted By: camrydriver111
It's interesting they report metals to 0.1 ppm. I didn't know AA was that accurate. I personally have a hard time believing they could distinguish between Cr 5.5 and 5.6 although I could be wrong since new instruments are coming out all the time.

The car seems to be OK with 0W20 as well.

Ah, 0.1 ppm is the precision of the measurement, not the accuracy. For example if you have a weight scale with 0.1 oz increments, 0.1 oz is the precision. The accuracy on the other hand could be, say +/- 2%, which would correspond to +/- 0.3 oz when you are weighing something that is 16 oz.

I didn't ask WearCheck about the accuracy but I am guessing it's +/- 0.5 ppm or more.

 

[Gokhan]

Originally Posted By: BigD1
Bar's Leak tablets are the same as the ACDelco tablets, and they are cheaper, and you get one more per pack too. NAPA and O'Reilly's auto parts stock them.

http://barsleaks.com/product/radiator-stop-leak-tablets/

Thanks for the info. They are probably very similar or maybe the same. I wanted to go with the OEM part [GM (ACDelco) part no. 12378255 (10-108)]. GM MSRP is $4.02. I got it from the local Felix Chevrolet for $4.50. It's 1 - 1.5 g per qt of coolant, with each tablet being 4 g. So, for my 6.6 qt system, it's no more than 2.5 tablets. I am hoping that it will work and it won't do any harm.

 

[BigD1]

There use to be two GM part numbers. The four gram tablets and the 10 gram tablets. The Bar's tablets are the 10 gram.

If you are using green conventional coolant, the secondary effect of the tablets is the cleaning of silicate deposits at the water pump.

I would crush and dissolve the tablets in hot/warm water until it is a liquid.

 

[demarpaint]

Originally Posted By: BigD1
There use to be two GM part numbers. The four gram tablets and the 10 gram tablets. The Bar's tablets are the 10 gram.

If you are using green conventional coolant, the secondary effect of the tablets is the cleaning of silicate deposits at the water pump.

I would crush and dissolve the tablets in hot/warm water until it is a liquid.




The last time I used the tablets I put them in a small envelope and smashed them with a rubber mallet into a powder and added it to the radiator. I like your idea too. They say you can put them in whole but......

 

[Gokhan]

Originally Posted By: demarpaint
Originally Posted By: BigD1
There use to be two GM part numbers. The four gram tablets and the 10 gram tablets. The Bar's tablets are the 10 gram.

If you are using green conventional coolant, the secondary effect of the tablets is the cleaning of silicate deposits at the water pump.

I would crush and dissolve the tablets in hot/warm water until it is a liquid.

The last time I used the tablets I put them in a small envelope and smashed them with a rubber mallet into a powder and added it to the radiator. I like your idea too. They say you can put them in whole but......

In my case making a liquid won't work because the radiator is always full to the cap. I am thinking of crushing them into a powder and then mixing them into the coolant with a plastic spoon in the radiator neck.

I wonder what's the difference between the old and new parts. The new part says 1 - 1.5 g (1/4 - 3/8 new tablet) per qt of coolant vs. the Bar's Leaks (old part) saying 5 g (1/2 old tablet) per qt.

 

[BigD1]

When I use the tablets dissolved in a few ounces of water, I just use a turkey baster, and remove enough liquid from the radiator, so that I can get in the tablet liquid. What coolant that was removed from radiator can be put in the coolant tank because a little bit over won't hurt it.

 

[Gokhan]

Thanks for the tip. They had the Pillsbury brand baster (and other kitchen tools) at the 99 Cents Only Store. I used it to draw some hot coolant from the radiator and mixed the crushed tablets in it in a container. They don't mix that well. Then, I put it back using a funnel and topped off the coolant. It looks like some of the seepage points (like near the the water outlet) had already been closed thanks to seeping coolant clogging them. Hopefully, the tablets will work in sealing the remaining seepage holes. I used 3 tablets (12 g) with the capacity being 6.6 qt. It says 1 - 1.5 g per qt; so, it may be a little more than the recommended dosage, but then perhaps not all of the crushed and mixed tablets went it.

I plan to put in Mobil 1 0W-40 SN next weekend. I don't know if somewhat high Cr and Pb is due to coolant contamination or 0W-20 viscosity not being sufficient but I will give it a try.

 

[Pontual]

Originally Posted By: Gokhan
Originally Posted By: Pontual
Could be 43ppm of ingested Californian beach marine salt?

I thought about it myself. However, the car is parked 4.73 miles from Venice Beach; although, I go there almost every weekend. 43 ppm Na is about 135 mg in 3.9 qt of 0W-20 oil, which is contained in about 343 mg of salt, and I doubt that much salt could get into the oil from the air that easily.

Also, something needs to explain the oil thickening. Perhaps, since it's an old-engine design, it tends to thicken the oil -- I don't know.


Let's see:

5.3k miles used about 145 gallons of fuel If Iam Correct. Multiply that by 14.7 and your engine breath about 7.5 tons of midly salt air, you only need that 0,34 grams of salt has dissolved on oil, after a bunch more had past throught the intake system. I think its doable!