i just got an oil change last month and rarely drive my z. i only drive it on weekends, so thats like 4 times a month and i only drive it to like the liquor store or some fast food place. today i checked my oil and it was pretty dirty and looks like it might need another oil change by the end of the month. is that normal assuming because its an old car?

Short trips like what you describe can cause the oil to darken up quickly.

It, the engine and therefore the oil, needs to get up to operating temperature, often, and stay there for a reasonable length of time.

This allows condensation and contaminants to be burnt off.

The less a car is used, the more often the oil needs to be changed.

Even on a regularly used car, I try to change the oil and filter at no more than 5,000Km intervals.

I don't think being an old car has much bearing on the situation, unless there is another contributing factor, like for example, too rich mixture.

Short trips once again where you barely push in the choke, if you have one, could cause fuel to be diluting the oil:rolleyes:

I have had a lot of old cars, and many of them have had symptoms like that. If there is a lot of gunk in the oil passages, or a lot of blow-by past the rings the oil turns black very quickly.

Oh, and I agree with Nissanman as well on the short trip theory.

The color of the oil is not generally a good indicator of when it needs to be changed.

What color is the Oil supposed to be BTW?

it always helps too if you make sure to get the car nice and hot when you change the oil. gets more of the residual build-up out.