notaguru

My low mileage '83 recently underwent an oil change: 20W50 Castrol. Only a few hundred miles later, the oil has gone from amber to a much darker color.

Aluminum engine? Something wrong?

wpgshark

How bad was the previous oil?

If you have very used oil there is enough carry over that it can discolor the fresh oil in very short order.

notaguru

The Castrol oil change was just before I bought the car, so I don't know what the previous oil looked like.

Jim Devine

The color isn't all that important. What's in it is. If the car is fairly new to you,
consider getting an oil anylasis- not expensive. Several of the owners have used Blackstone Labs- it's a very detailed report. They send you a collection kit free & you pay when they run the test. It will show bearing material, any metals etc.

http://www.blackstone-labs.com/

mike77

May just be a sign that the additive package is doing its thing and cleaning the engine. Dirt is being removed from the engine surfaces and suspended in the oil.

VehiGAZ

notaguru, how LONG ago was that few-hundred-miles-ago oil change?

Perhaps they only changed the oil then and left the dirty-oil-filled-filter in, so the color is due to what was left in there.

I wouldn't sweat it either though, but do the Blackstone analysis as a baseline/reference report.

And in general, I suggest to ignore all claimed history and baseline everything - all fluids, filters, belts, etc now that it's yours and you can actually knowfor sure what's being done to it.

UpFixenDerPorsche

I'm generally in agreement with previous comments, although unless you drive permanantly in Death Valley I might question your choice of viscositiy.

If the PO has either not changed oil regularly, or has used $1.99 El Cheapo brand your engine may have accumulated a lot of sludge, that will be dislodged by the action of high detergent levels in any 'brand' oil.

Two thoughts:

- use a de-sludge additive from Nulon or other good brand, then change your oil/filter within a few hundred miles, or

- continue using Castrol, changing the oil every few thousand miles until it stops darkening so quickly after a change. This will occur over time if it is just a matter of de-sludging the engine.

If, over time, none of this works, then you may need to look at ring wear. A leakdown test would be a good guide for future action.

HTH

notaguru

It was the PO that did that oil change, and the bill indicates that the filter was also changed.

Thanks for the link to Blackstone. I used SOAP (the Spectrographic Oil Analysis Program) many years ago for aircraft engines, and forgot all about it. This is a great idea!

So - San Diego, where the weather is never VERY anything... What is the consensus on oil for this environment?

jcorenman

What color "darker"? Brown? Black? Something else?

Your first post was a week ago, so I am guessing that we're talking two weeks-- correct?
[Sidebar: Why make us guess?]

I am not accustomed to seeing the oil color change appreciably over a few hundred miles with these engines. After a few thousand, when it gets changed, yes it will be quite a bit darker on the dipstick.

If it is getting dark quickly then either it was very dirty previously (as mentioned), or something is wrong. A Blackstone report is very useful in either case, but would be more useful if the history was known.

Since the previous history is unknown I would change oil & filter again now, to eliminate any significant carryover and also cut open the filter and have a look at what it has filtered out.

Then drive it another few hundred miles and if it quickly darkens again then pull another sample, otherwise wait for the following change.

We generally send off a sample at each change, and cut open the filter.

NOOOooo..... Not another Oil Thread!!??

Do some searching here, opinions vary. Most will recommend 15w50 or 20w50 for moderate climates, make sure the ZDDP level is adequate, and a decent brand. I am not familiar with Castrol's current oils, we use Brad Penn or Torco these days. We also send off virgin samples to Blackstone for oils that we are considering, so we have a baseline for later comparison.