Motor breaking oil down too fast?

[GotToyota?]

I have a 95' Toyota Celica, which has been given Pennzoil Platinum for the last two oil changes. The first change I changed the oil around 4,000 miles, and the oil was already pretty broken down. As for this current change, it almost has 3,000 miles on there, and it's already broken down quite a lot as well. On this car, which I find hard to believe, Toyota recommends changing oil every 7,500 miles with normal driving conditions and 5,000 with "extreme" driving conditions. Is it bad that the motor is breaking down oil this quickly, or is this somewhat normal?

BTW, the motor is a 5S-FE, using 10W-30 PP, with a Napa Gold filter.

-Matt

 

[jdub]

How do you know the oil is "breaking down"?

 

[johnathan1]

I'm guessing lower oil pressure as mileage increases?

 

[GotToyota?]

Jdub, call me a n00b, but I thought the "broken down" status was based off the color of the oil. For example, the darker it is, the more broken down it is, maybe I'm way off here, lol.

-Matt

 

[starscream5000]

Are you sending your oil out to a lab to be tested to determine that it's breaking down? A place like Blackstone labs? Or are you just thinking this becuase the oil is getting dark? What oil filter are you using?

If you say this because the oil is getting dark, that means that the oil is doing it's job by cleaning the engine (along with cooling it). Try changing your oil filter out every 4000 miles if this is the case (don't forget to replace the lost oil from the filter change).

 

[johnathan1]

Dark=dirty. Oil getting dirty is totally normal...that doesn't mean it is protecting less.

 

[jdub]

^^^ What they said
http://www.blackstone-labs.com/

Your oil will get dark over time...if you use a by-pass filter in addition to the full flow you have now, it will take longer to get dark, but eventually that will occur. The only way to tell if oil has lost it's effectiveness is with analysis. Pennzoil Platinum will easily go 8K between changes. NAPA Gold is an excellant filter.

Johnathan - Oil will lose viscosity over time and "settle" between the viscosity numbers on the bottle. You "may" see a slight oil pressure decrease as a result. If you see a significant decrease in pressure, it is much more likely something is going on in the motor...oil pump, bearing clearances, etc.

 

[GotToyota?]

Awesome, thanks for the info guys, seems as if the oil is doing it's job.

-Matt