dirty oil
 

i have an 89 lx with 99000 miles on it. i change the oil every 3000 miles and within 500 miles the oil starts to get pretty dark. i dont beat the hell out of the car all of the time, culd this be because the car does not get to a high enough temp to burn the dirt off?? i have a 180 thermostat, flex fan, and a hihg volume water pump, which usually keeps the temp below 180. by the way i use mobil one and a mobil one filter, any help as to ehy the oil gets so dirty so fast would help

My F-150 has 66k miles on it, and I change the oil and filter every 3000 miles. I use Mobil 1 oil and Napa filters. My truck never gets hot. When I change the oil, every 3000 miles, it looks virtually as clean as it did when it went it.

I would flush your engine before you do your next oil change. That, and make sure you change your filter when you change your oil. Also, replace your PCV valve.

Take care,
-Chris

HHHHHMmmmm....do you operate in a dirty environment?, dark oil in 500 miles does sound a little strange, Desert storm helicopters oil was dark on startup with a fresh change, i know i was there.but, unless your having pressure problems i wouldn't worry, start beating the crappola out of it and see if your don't beat on it theory proves true?

When I took my pan off I was surprised how much junk lays in the bottom after you drain the oil. I cleaned everything real well before I put it back together and the oil stays clean longer.

I change my oil by sight.
I don't buy the "minute lube" recomendation of 3000 mile changes because of the research that shows that oil doesn't wear out, it just gets dirty.
My stang has 150K on it and a fresh oil change & filter never stays clean for long. It tends to stay somewhere in betweeen clean and black, which works for most driving conditions.

You can always spin on a new filter more frequently if you want to be on the safe side. 2000 mile oil changes are alot cheaper that sigging into the cause of dirty oil. It's a matter of dollars or some cents.

I change my oil by sight.
I don't buy the "minute lube" recomendation of 3000 mile changes because of the research that shows that oil doesn't wear out, it just gets dirty.
My stang has 150K on it and a fresh oil change & filter never stays clean for long. It tends to stay somewhere in betweeen clean and black, which works for most driving conditions.

You can always spin on a new filter more frequently if you want to be on the safe side. 2000 mile oil changes are alot cheaper that sigging into the cause of dirty oil. It's a matter of dollars or some cents.

I've seen brand new cars get dirty oil almost immediately after you start them because you can't get ALL the oil out during an oil change. One way make sure you have very clean oil is to change your oil, start the car and let it run for a few minutes and drain and refill the oil again. This gets quite a bit of the old oil out. I also think the time you change your oil is dependant on the condition of your engine. If the engine burns oil there will be more sludge buildup than one that is fresh. Oil also tends to seperate and turn into sludge faster with older engines that comsume more oil, also carbon builds up faster in older engines. 3,000 is a safe bet for most vehicles, but you can get away with longer oil changes if the oil isn't being burnt or if the filter is still actually filtering (not bypassing) by that time. I don't risk it, i usually go 3,000 miles just because of the fact that your oil may be good for 5,000 miles, but you never get all of the old oil out, plus if extra dirt gets into your engine somehow (crack in airbox, vacuum leak, skip in gasket sealing, etc. etc.) or small pieces of gasket/carbon falls down into the pan it can clog up the filter fairly quickly with relatively "small" amount of debris. This is just my opinion though, based on what i've seen working on cars.