My Volvo is a 1995 850 GLT. The odemeter is broken and I estimate it has 220K miles on it. I have owned it since July 2009. My son filled it with Castrol GTX high mileage oil in the last oil change. I had used various brands of motor oil in it before. The results were all about the same. The oil would be a dark honey color when I changed it at 3,000 miles. Now my car has approx 1,500 miles on it and the Castrol oil is already black. Yecch !
All comments and opinions are welcome.

 

different oil with different detergents will probably remove different deposits. As for the mileage, you DO know that you can use the diagnostic box to get actual mileage, right?

 

What do you mean by a diagnostic box? Where would one find one of these?

 

https://volvoforums.com/forum/volvo-850-16/how-get-actual-mileage-93-95-850-volvo-27012/

 

Thank you Ibified !
I did not know how to get the actual mileage. I will try it sometime in the future. Your reply "different oil with different detergents will probably remove different deposits...." did remind me of one thing I did not mention before. My son performed an "Engine oil flush" prior to filling it with Castrol GTX HM. I assume that would have removed a lot of deposits before he added the Castrol. What is your opinion concerning "Engine oil flushes" ?

 

I have no opinion, really, because I have never done it.

 

I hear "stay away from US Castrol", but I also see that many people use in their Volvos. Besides it is recommended by Volvo (in the mid 90s). What's the deal here?

 

Back in the old days, we would take one quart of diesel fuel and add it to the engine, run it for 2-3 minutes and drain it. Nowadays, one can buy the Engine Flush at Advance Auto Parts or any chain store like it. It seems to be diesel mixed in with some other stuff. One performs the same procedure. The engine is run for a very short time, then drained. The results are spectacular. All carbon build up, sludge, or whatever is totally cleaned out of the engine. At first, we would only perform an engine flush as a last resort. We had a 1988 Chevy with 88K miles on it, but it was smoking. Additives were of little use. I did not want to go into the engine. We performed the engine flush. The results were instant. All of the carbon build up and sludge were gone. The car never smoked again. It was like a miracle!
Having said all of the above, I would do an engine flush only on an older car with lots of mileage and a questionable maintenance history. My son thinks it should be done every three years.