Extend oil change interval?

[Kuato]

Originally Posted By: 2civics
http://www.blackstone-labs.com



Right.


Originally Posted By: 2civics

The only thing I question in your situation is how valid your results will be with the amount of oil change-out you have to do. Some of the guys here will be better able to tell you whether they think you'd get your money's worth from a UOA considering you are burning and replacing so much oil. The analysis costs $25 and is an extra $10 if you get the TBN done. What is the TBN? It's an add on testing that is over my head at the moment (has something to do with testing the additive package and how much further you can go on that oil??) and so the other guys will be better able to explain that as well if you are interested.


2civics, OP has to add oil during his OCI, that is a constant. Once he has the UOA and posts it up, he'll get plenty of comments. It will show the condition of the oil at the time the sample was taken and from the numbers we'll be able to tell if it's time to change the oil, or estimate how much further it can be safely run.

Blackstone, with the TBN (Total Base Number), will tell you both how much active additive remains, and also give an estimate based on other UOAs for that engine, how much further they think the oil could be run.

 

[bigt61]

Just change it every 5k. As long as you're keeping it topped off, you'll be fine.

 

[TonyDee]

I received the UOA yesterday. I'll post the results in the UOA forum.

Thanks for your help here/.

 

[stchman]

Originally Posted By: TonyDee
Hi all. New here. Love the place. I've already searched for answers to the questions as to whether or not I an mix conventional and synthetic oils and viscosity.

I have a 2001 Buick LeSabre with the 3.8L engine, about 73,000 miles.

I have to add a quart of oil about every 1,500 miles. My mechanic says that is fine. There are no oil leaks and emissions tests are good. So where's the oil going?

Anyway, the car's manual says that I should change oil every 3,000 miles because most (but not all) of my trips are in the suburbs and of about 10 miles each. They call it City duty.

Since I add a couple of quarts of oil every 3,000 miles which replaces old oil, at 3,000 miles, I've already changed out 2 quarts of oil. The old oil has been replaced with new oil. With that, I think I can extend oil changes to 5,000 miles.

Does this make sense?


First thing is to replace the PCV valve, malfunctioning PCV valves have been known to cause a great deal of problems. Simply pulling a valve out and shaking it is NOT a proper method of testing. A PCV valve is a somewhat precise device and meters airflow by the weight of hte plunger and how stiff the spring is. They are relatively inexpensive, so just replace it.

Second, try using Mobil 1 or another name brand synthetic oil, synthetic oils are less volatile and might reduce any oil consumption.

Forget getting a used oil analysis unless you are going to do LONG drain intervals (over 10K miles). A used oil analysis cost $35 from Blackstone with TBN. For that price, you could simply change the oil.

Give Mobil 1 and a Fram Tough Guard or Fram Ultra oil filter a try. Go 5K miles and keep an eye on your oil level to see if it using less oil.

 

[Snoman002]

No need to do repeated UOA's, but a few testing different OCI's can save you money in the long run. Think of it as an extra payment on your mortgage, one up front can save interest payments later. If the UOA tells you that you can go 10k the $35 spent will save you two unneeded oil changes for the indefinite future.

The GM OLM is generally considered to be very good. Basically stated it measures the revolutions of the motor and the engine temp (and a lot more). High RPM's at a cold temp will cause the % to decrease faster than high RPM's at a normal temp, than low RPM's at a high temp, etc. In your case, if consumption remains the same, you might be able to run the OLM to zero twice before changing the oil. You will need to run a goo filter to do so however.

As for consumption, as said try a PCV valve, it may help. If it's not leaking then it is burning, and you could try a few things if you wanted. AutoRX, MMO, Seafoam or high mileage oils all come to mind. If you ambitious try pulling the throttle body and looking in the intake, if it's covered in oil film a low NOACK oil could help.