I am still having problems with my oil going dirty/dark brown quick after an oil change.

On average I am changing my oil every 1250 miles.

I basically change it every 2 months or when/If if its dirty or i get HLA noise on start-up.

I am using Millers 10w 40 semi synthetic oil which is a good brand in the UK.

It s not a BIG problem but just wanted to know if this is normal for the other greddy guys.


My car has done about 84,000 miles and for a 14 year old car and i have tried Fully synthetic oil, but my car does not like it. I had silly oil leaks develop when i switched to fully synthetic probaly cus it is thinner oil. i changed the seals and switched back to semi synthetic and they went away.

 

I had no leak problems going to Mobil 1 10w30, but my oil gets darker pretty much at 1000 miles. Used to be that pre-turbo oil couldn't be seen on the dipstick when I changed every 3000 miles. I have written it off to the Turbo addition.

 

thanks for that.

any other turbo/greddy guys care to comment?

 

My royal purple starts out a little dark, but definately doesn't take long to get even darker.....

All I do is monitor the level, and keep and eye on when to do the oil change... Of course, I look for "bits" when doing the change too, just to keep an eye on how the motor is doing.... <G>

I must say, the addition of the new motor, its very nice not to have the add oil every 1000 kms. <G>

Dave,

 

As far as I understand turbo cars generally "darken" the oil faster. Just be happy it's not a diesel, that oil seems to go black after a few mins.

 

My Audi diesel used to do that

 

an explanation i have been given which I am not sure to believe is that using semit synthetic oil, the mineral part is burning form the heat generated form the turbo as it it not a synthetic oil.

I was told a with a fully synthetic oil this will not happen. i will not switch to it again however and have oil leak throught the 14 year old seal cus its so thin and into the clutch/bell housing ruining my expensive exedy racing clutch.

however, your replies are good enough for me.

that means on average I do 6 oil changes a year.

does that not sound excessive considering I do approx 7500 miles a year.

 

This will still happen. Due to the heat that the turbo adds, the oil just naturally breaks down faster. When doing an oil change look for any water on top or fuel, that is when you start shitting your pants. Also, with the turbo you will get just a little bit more blow-by the rings, which that little tiny bit extra helps to break down the oil even quicker. My camaro does this now that I am running an 11:1 ratio also, because the added compression adds to the blowby of the cylinders.

 

even when i was NA i oculdnt get mibil full synth to last more than 2000 miles before it got used up. Q from quaker stae full synthetic is good better than the mobil even and royal pruple goes 3K miles even wiht the turbo. but it is atleast 7 bucks a liter. this or an oil cooler are youre only options.

 

How do you know the oil is "used up"? Even people with oil coolers have remarked that with the turbo the oil gets dark pretty quick.

I wonder how much of that is due to running rich?

 

i didn't think color was any real indication of the condition of the oil, either way i wouldn't worry about it

 

2nd.

 

I bought a car with ~30K miles on it a few years ago, had the same problem...(mobil 1) I pulled the oil pan and found about 1/2" of sludge caked in the pan... I cleaned up the pan, and between the first couple of oil changes it was almost impossible to tell that there was even oil in it.

So there might just be sludge on the bottom of your pan???
Pulling a miata pan isn't as easy some other cars because of the subframe clearance though..

 

The main indicator of oil is the smell. If the oil smells like it has been baking, then the oil has broken down. If the oil is coming out and there is a severly overpowering smell to it, then the oil has broken down. Something to try and do to clean the oil pan out is to run seafoam cleaner through the oil system. DO NOT RUN FOR MORE THAN 200 miles like this though. Even though seafoam is 100% petroleum, it will be a precatalyst for the oil to break down. It cleans out the oil system really well. Also, when I tore apart my gen2 sb chevy the bearings had been micropolished and looked immaculate. If they would have been thicked, I would have reused them for just a stock rebuild. I owe this all to royal purple, that oil is the ****. Just my opinion though, do whatever makes you happy and what you feel is the best. Also, my greddy came in today, yes, let the fun start. I can barely keep myself out of the garage. I want that and the emanage on there so badly I am salivating.

 

smell and hla's tell the story also you will notice abit less hot pressure with oil that has broken down into a lower vistocity range.

 

You want to know how your oil is holding up? Then have an oil analysis done. That's the only way you'll ever know for sure. Looking at the color of your oil and coming to the conclusion that it needs changing is silly if not downright stupid.

My oil shows excessive amounts of silicon which is basically dirt. Here in Arizona, with the desert air and plenty of new housing construction, we have a serious problem with dust. The high aluminum content is due to the silicon wearing out the cylinders - Aluminum and silicon = Aluminum Oxide = SANDPAPER!

Other then the dirt, the oil would have been good for at least another 1000~2000 miles.

My plans are to be very diligent about cleaning and oiling my K & N air filter.

 

I hope you don't have aluminum cylinder walls. My guess is that the silicon is wearing the aluminum from things like piston skirts and cam journals. IMO your aluminum count is VERY low. That's very good. - rob

 

I was trying to remember exactly what the analyst told me over the phone.

However, the aluminum content for my car is more than double the Universal Norm. According to Blackstone, the Universal Norm is for ALL of the Mazda Miata 1.8 engines they've tested historically.

Also, the last time I cleaned my K & N, I didn't oil it which hopefully is why I got all that dirt into the engine. I'll wait to do another oil analysis in 3000 miles. If I still have all that silicon, then I'll be replacing the K&N with something else.