Toyota (TGMO) 0W-20 SN, 5,306 M, 85 Corolla 4A-LC

[Gokhan]

I've now got the UOA results on the Toyota (TGMO) 0W-20 SN fully synthetic, made in USA by ExxonMobil.

The results seem to be slightly better than the previous results with the PYB 5W-20 SN dino. Toyota 0W-20 SN is also rather thick, almost as thick as a 5W-30. In fact, I think most 5W-30s shear to smaller viscosity. So, it's thicker than most 5W-30s after they shear. This is a good thing for me, as I want the added protection of slightly higher hot viscosity as well as the super-low cold viscosity of Toyota 0W-20 SN thanks to its ultrahigh, 220ish viscosity index (VI).

The two concerns in the UOA are high chromium and sodium. I've been collecting the hot oil sample in a tin mint-candy box. I am suspecting that chromium might be coming from the plating of the tin box. I was also washing the box with soap and rinsing it many times with water, and there is a possibility that sodium might be coming from the soap-washing. These are speculations though, and I asked these questions to Blackstone as well. Next time, I will try to directly sample the oil in the plastic bottle.

Discussion and comments are welcome.

 

[147_Grain]

The sodium is likely from a small leak from the well-worn headgasket. Would recommend you stick with 5-6K oil changes with 5W-20 or even 5W-30 weight oil in the Southern California heat. Your engine has 250K on the clock and might benefit from a 5W-30 weight oil.

The higher than normal viscosity might be from the much thicker / leftover 15W-40 diesel oil from the last LOF change.

 

[cathy]

did u specifically look for this 28 year old car? How did u endup w this?

 

[Gokhan]

Originally Posted By: 147_Grain
The higher than normal viscosity might be from the much thicker / leftover 15W-40 diesel oil from the last LOF change.

It's not technically higher than normal. xW-20 can go up to 9.29 cSt at 100 C without being classified as xW-30.

15W-40 was two oil changes ago. Previous oil was PYB SN 5W-20 dino and its UOA viscosity was less than that of Toyota 0W-20 SN.

 

[martinq]

Excellent. Hope you continue to use and test this oil. I'd be interested on how this trends-out.

Would suggest trying to find a better sample-collection container if possible. Why not drain directly into the sample container when changing the oil?

 

[getnpsi]

A toyota in California can be parked with a bad clutch or other lame excuse for 15+ years and take back up into service right where it left off. Many fully functioning cars got parked as they aged (the owners) as so many out there are factory no A/C. I do have friends from other parts of the country and they treat a target parking lot as a car show at times, getting all excited over peoples daily buckets!

 

[Gokhan]

Originally Posted By: martinq
Excellent. Hope you continue to use and test this oil. I'd be interested on how this trends-out.

Would suggest trying to find a better sample-collection container if possible. Why not drain directly into the sample container when changing the oil?

Thanks. The reason I collected it with a shallow tin can last couple of times was because there is very little clearance between the oil pan and the drain pan. I will try to find a shallower drain pan next time so that I can get the bottle in between.

The new oil in the engine is also Toyota 0W-20 SN and apparently from the same batch as the last time.

 

[Gokhan]

Originally Posted By: getnpsi
A toyota in California can be parked with a bad clutch or other lame excuse for 15+ years and take back up into service right where it left off. Many fully functioning cars got parked as they aged (the owners) as so many out there are factory no A/C. I do have friends from other parts of the country and they treat a target parking lot as a car show at times, getting all excited over peoples daily buckets!

I've had it for 18 years now. I've been repairing and maintaining it mostly myself and that's why it's running so well. Note that it only consumed (mostly through a small leak at the oil-pan seal) less than 0.4 quarts in more than 5,000 miles with 0W-20. I've used no makeup oil at all in both oil-change intervals (OCIs) in the report above. The 28-year-old girl is way better than 10-year-olds out there in terms of oil consumption. It's thanks to me having replaced the valve-stem oil seals.

 

[Coprolite]

If you plan on doing many UOA, why not invest in a little suction device and some tubing to go down the dipstick tube? I am sure there are UOA specific ones available, but a harbor freight brake bleeder kit is easy and cheap to get, also.

 

[buster]

TGMO is surprisingly shear stable for an ultra high vis 0w20.

 

[fdcg27]

The sodium may be of some concern, but this UOA of a 0W-20 from an engine built long before such a grade was even considered looks really good.
This UOA can be a poster child in the next thick vs thin thread.
This engine has apparently held up really well over many years and miles.
While there may be some doubt about Toyota quality these days, this was clearly a car built when no such doubts could be justified.

 

[Capa]

Fantastic result, though I do wonder if with the TBN you would reach 10,000 miles?

 

[Gokhan]

Originally Posted By: Capa
Fantastic result, though I do wonder if with the TBN you would reach 10,000 miles?

Thanks. Good question about TBN. It's better than PYB 5W-20 but it did get pretty low. I don't know if the TBN decreases linearly over the entire OCI. It could be that it's not so and more miles pass between 2.5 and 1.0 than between, say, 8.0 and 2.5. The other concern would be the possibility of oil-filter clogging after a while.

Perhaps high sodium and chromium is a result of my sampling using the tin can. Let's see what Blackstone will say. I will try to directly sample it next time.

 

[ZFoily]

Originally Posted By: Gokhan
I've now got the UOA results on the Toyota (TGMO) 0W-20 SN fully synthetic, made in USA by ExxonMobil.

The results seem to be slightly better than the previous results with the PYB 5W-20 SN dino. Toyota 0W-20 SN is also rather thick, almost as thick as a 5W-30. In fact, I think most 5W-30s shear to smaller viscosity. So, it's thicker than most 5W-30s after they shear. This is a good thing for me, as I want the added protection of slightly higher hot viscosity as well as the super-low cold viscosity of Toyota 0W-20 SN thanks to its ultrahigh, 220ish viscosity index (VI).

The two concerns in the UOA are high chromium and sodium. I've been collecting the hot oil sample in a tin mint-candy box. I am suspecting that chromium might be coming from the plating of the tin box. I was also washing the box with soap and rinsing it many times with water, and there is a possibility that sodium might be coming from the soap-washing. These are speculations though, and I asked these questions to Blackstone as well. Next time, I will try to directly sample the oil in the plastic bottle.

Discussion and comments are welcome.

Any trace of coolant is serious, the anti freeze will trash the detergents and cause sludge. It's the no 1 cause of lubrication related main block failures according to Blackstones, so I would not ignore their warning.
The engine is in good condition, but if you can't afford a new HG job to stop the leak, or it is not an economic repair, then firstly I would dump the present fill (Keep the oil filter in use if you wish), switch to an HM 5/30 from a major brand and add a can of stop leak to your coolant.
If you are not exposed to below zero temps, dump the coolant and fill with water, a can of soluble oil (Marine engine anti corrosive), then add a can of major brand stop leak to the coolant mix. It might look like a nasty light brown mix, BUT it will do far less damage than anti freeze in your oil!
Once the leak seals up or you get it fixed (Might just be a head bolt if you are lucky), then 10K miles might be a target OCI, IF you want to extend via 7.5K miles and another UOA first.
Not sure about the Cr figure as it looks OK in statistical terms, but if it trends up then think about changing to a high Zinc content oil. The 0W part will make no difference in LA, unless you head for the mountains and below minus 25C it is a non factor in start up wear terms.

 

[buster]

Coolant could also be why the viscosity is creeping up a bit.

 

[Gokhan]

Yes, however, I am not 100% convinced that I have a coolant seep into the oil. It's certainly quite possible with a 28-year-old head gasket. I need to sample directly into the plastic bottle instead of the tin can next time to make sure that the sodium didn't come from washing the tin can with soap and the chromium didn't come from the plating of the can.

Ingredients in Simply Ivory: sodium tallowate and/or sodium palmate, water, sodium cocoate or sodium palm kernelate, glycerin, sodium chloride, fragrance, one or more of the following: coconut acid, palm kernel acid, tallow acid or palm acid, and tetrasodium EDTA.

Ingredients in can plating: chromium, zinc, etc.

 

[147_Grain]

It is highly likely that any 28-year old engine and head gasket are leaking a little bit.

Odds are high that this is your problem and not the tin can.

 

[Coprolite]

Just suck a sample through the dipstick tube. The results will give you an answer and course of action.

 

[Gokhan]

I should also add that the car was driven in extreme conditions as well, including a round trip to Las Vegas where there are a lot of steep grades you climb in excess of 70 MPH in hot weather. That's virtually full throttle for this 74 HP engine. There were also a lot of very short trips less than 2.5 miles.

The oil loss in 5,000+ miles was very small, about 0.3 - 0.4 quarts, probably mostly due to a small leak at the oil-pan seal.