Low TBN

[buster]

Tooslick mentioned that I check the EGR valve on my car as a possible cause of the low TBN's of all my UOA's.

I'm not quite sure why, but all the oils I have run, RL had a very low TBN of only 2.6 after only 5k miles of highway driving. Amsoil and M1 did much better. I was told that the o2 sensor in my car doesn't have to be replaced at any specified time. Spark plugs still have life left in them. My gas mileage is not the same as it used to be but it's still decent. No hesitation or rough idleing either at stops.

Does anyone have any other suggestions or reasons why the TBN drops so rapidly in my car? Thanks

[ December 04, 2003, 05:46 PM: Message edited by: buster ]

 

[Quattro Pete]

Is it only an issue with your car or does the TBN of RL deplete quickly in most cars?

The reason I ask is because with some oils, the TB starts high, but depletes quickly, regardless of engine.

 

[buster]

Well RL dropped much quicker, but even Amsoil/M1 at 5k miles was down to I think about 4/5. I'd have to double check. It just seems for highway mileage that this engine is hard on oil. It holds 4qts.

Not to mention I added almost 2qts of makeup oil with RL!

 

[Drew99GT]

If your EGR was even partically stuck open, it would set an excessive flow code. The valve has a flow meter with a potentiometer and the ECU knows when the valve is supposed to be open and when it's not.

 

[buster]

Thanks Drew. Might just be from switching oils. RL does show a drop in TBN very quickly compared to other synthetics as mentioned by TS.

 

[Drew99GT]

Speaking of EGR systems, my 94 Corolla is supposed to have one (7AFE) according to my service manual, but it doesn't have one!

 

[Motorbike]

quote:

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Originally posted by buster:

Not to mention I added almost 2qts of makeup oil with RL!

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When a motor burns much oil in it's life eventualy the 02 sensor will get coated as will the cat converter without regard to design all will take this hit....it's a matter of time.

If your car is down on power and milaege it might be a bit of both and if the cat is clogged it will labor causing a bit more heat from backpressure.

You might have it checked given the history and miles .

 

[slider]

quote:

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Originally posted by Quattro Pete:
Is it only an issue with your car or does the TBN of RL deplete quickly in most cars?

The reason I ask is because with some oils, the TB starts high, but depletes quickly, regardless of engine.

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I'm not sure how accurate Blackstone's TBN test is with Redline. It's suggested that the esters can skew the test to the downside. There was post here a while back about a vrigin sample analyzed by them, and it came back as 8.5, while RL specifies 10 and other labs show closer to RL spec.

Blackstones current method seems compressed, even with other brands. TBN isn't an exactly precise measurement with any lab.

 

[Robbie Alexander]

quote:

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Originally posted by buster:
Tooslick mentioned that I check the EGR valve on my car as a possible cause of the low TBN's of all my UOA's.
-*-*-*

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I don't know enough about the numbers to be able to pinpoint it like that, but I do know that too much WEAR, will cause it to drop like a rock, or a combo of Wear and Si or All bottom end wear.... The key thing is anything getting into the oil in excess...