It's a common practice in the heavy duty diesel engine industry. Many of the over the road trucks you see will easily go 25,000 miles without an oil change. They will change the filter out and top off the oil, which helps replenish the additive package, and they are good to go. Chevron did a test quit a few years ago and got a million miles out a heavy duty diesel engine before they had to do an overhaul. Now that's impresssive.

 

I noticed my L and my wifes Expedition both have black oil. I do not know if it is due to blow by or what. I also had a VW Siroco with 250,000 miles and the oil came out about the same color that it went in. This 5.4 motor runs dirty. My 911 has the same dirty oil but it is air cooled ... lots of expansion on warm up. I change my oiul at 3,000 miles and get great engine life in everything but the L. New engine at 45,000, blown plug.

 

I remember reading recently the best way to test it is to take some of the oil and rub it all over yourself and roll in sand.

if the sand sticks then its still okay
if it doesnt then you need to change it.

I think i got that info on a SRT-10 board or something!!???

 

hmm-- well thanks for all the replys--- I guess that there isn't a big concern. I will try the DEIMATT sand method , but since i don't live by the beach i will substitute kitty litter....

 

Seriously folks,
Anyone remember the Franz oil filter?
http://www.utterpower.com/oil.htm

Nothing like toilet paper to clean up a mess

Amsoil is another company that uses a bypass oil filter system but I have it on my Diesel Dodge and the oil is still very dark.
http://www.bestsyntheticoil.com/amsoil/by-pass.shtml

Using the bypass system it takes aproxamately 20 minutes of highway driving to clean all of the oil one time.

Being in the air conditioning industry I can tell bypass systems do work well. We use the same principal on open condenser water systems as well as closed loop systems.

The problem with full flow systems is that it can be restrictive and there are limitations on size.

--------------------------------------------------------------------------------
How many of you folks know that much of the time your oil is not being filtered at all... ?

Your average oil filter has two valves in it.

One is a check valve to keep the oil filter from draining when the engine is not running. (Our engine has the filter in the vertical position)
The other is to let the oil flow at higher pressure such as High RPM and cold start ups.

 

we are soooo the same, I was thinking someone might reply with kittly litter..LMAO!!

 

thats not wise, just fork out the 22 bucks for the oil at costco and 10 dollars for the k&n at kragen every 3000 miles and dont worry. Be nice to your engine, it gives you so much happiness.

 

Reason the oil turns black is because its doing its job. If your oil is coming out as clean as it did when your poured it out of the bottle id change your oil brand.

 

It is VERY, VERY important to change the oil regularly in a stock L. If you don't, you can end up with a very nasty looking intercooler.

I change mine every 3k miles, and I sleep well at night knowing that fresh Mobil1 is the only oil in MY intercooler!

 

I'm definitely not an expert on oil, but I do have an observation to share. I have a 1965 Mustang, 289 cubic inch V8 with Holley 4 barrel carb, 3 speed auto. I wrenched on that thing throughout high school, and I'm still workin' on it 15 years later.

Anyway, a few years ago, I rebuilt the carb, and initially jetted it a little too rich (had no choke). I drove it like that for a while, but the poor gas mileage and smell of gas vapors was getting old. When I changed the oil out, it was black, I mean pitch black. Still felt slippery though. Before I did the carb rebuild, the oil was darker at oil change time than when new, but you could still see through it.

So I re-jetted the carb to leaner settings, and drove it around for a few thousand miles. At oil change time, the oil was darker than new, but not nearly as dark as the oil that was used during the richly-jetted settings. And up to now, the oil has never been too "dark".

So my guess was that with the rich gas mixture, during normal blow-by, the excess gas was diluting the oil, and the PCV system wasn't enough to extract the excess gas vapors from the crankcase.

So, could darker-than-normal oil in a fuel injected engine be due to an engine that's mapped too rich? Anyone know?

 

LMMFAO!!!!!!!!!!!!!!!!!

 

Read the dark oil myth sections below...

http://www.quakerstate.com/pages/carcare/whattoknow.asp

http://www.nordicgroup.us/oil.htm#Th...k%20Oil%20Myth

 

I can't understand why anyone would hesitate to change the oil every 3 to 5k miles. It's so cheap in terms of vehicle ownership, and provides a lot of peace of mind (at least to me).

 

I change mine at every 3k. It makes me feel good to do my part for mother earth, to help clean up a huge toxic waste problem known as oil reserves…

”When in doubt, drain it out…”

 

I just switched to the Amsoil 5w30 motor oil. It says extended oil changes every one year or 25,000 miles. I also installed an Amsoil oil filter which is good for 12,500 miles. I plan on changing the oil filter in 12,500 miles and then new oil and filter at 25,000 miles. I ran the Mobil 1 5w30 but had to add a quart every 1000 miles. I already have 2000 miles on the Amsoil and the dipstick level is still good. I will watch the oil level this summer to see if extreme heat causes any oil usage/leakage. I am very happy with the Amsoil motor oil and filter so far...