1997 850 NA - Switched to Pennzoil 5W-40

Post by **xHeart** » 12 Mar 2016, 07:36

It is now more than 40,000 miles since the PCV (5+ yrs), and regular oil and and filter change every 4-months. It has been running very well - no motor issues.

But, It burns a quart every 3000 miles in urban driving.

Several posts at MVS suggest 5W40 could be a better choice. I am upgrading from conventional Pennzoil 5W30 to All Synthetic Pennzoil Euro 5W-40.

So my goal is sustain PCV, oil change once a year, and not have to add an extra quart between the oil change.

Any thoughts?

Post by **abscate** » 12 Mar 2016, 08:25

How many miles are you driving every year ??

40,000/5 is 8k, in which case just go to synthetic and change once per year

Post by **dosbricks** » 12 Mar 2016, 08:48

5W40 might cut your oil consumption by one half at best, but as an additional benefit it will clean up your engine over time while reducing wear.

Post by **j-dawg** » 12 Mar 2016, 11:05

Just a quart every 3000? The gods extract from you but a meager tribute.

Post by **abscate** » 12 Mar 2016, 11:37

j-dawg wrote:Just a quart every 3000? The gods extract from you but a meager tribute.

Nice prose, well done.

ThommyKent · Post by **ThommyKent** » 12 Mar 2016, 13:01

dosbricks wrote:5W40 might cut your oil consumption by one half at best, but as an additional benefit it will clean up your engine over time while reducing wear.

How does it clean engine?

Post by **dosbricks** » 12 Mar 2016, 19:41

ThommyKent wrote:
dosbricks wrote:5W40 might cut your oil consumption by one half at best, but as an additional benefit it will clean up your engine over time while reducing wear.
How does it clean engine?

I should have been more clear and indicated synthetic oil, not just a different weight. Synthetic doesn't contain the paraffin and some other undesirables found in dino oil, so it's detergents can be more effective in dissolving the existing sludge in the engine.

If you want to get down on the molecular level (this is abscate's territory), basically in synthetic oil, all the molecules are the same size--small. In dino oil there are small medium and large ones, so the large ones can tend to block up in tight places followed by the medium ones and then keep the small ones from flowing through. And we all know little molecules (like Little Scrubbing Bubbles *TM) clean better.

Does it seem like I don't know what I'm talking about? Probably. So I will speak from personal experience. About 18 years ago I bought my 850 wagon. It had a very low grade dino oil used in it for it's first two years of life and already the engine was brown inside (as observed through the oil filler), and I immediately switched it to full synthetic, and over the next couple of years it slowly cleaned up inside. So there you have it, a first hand testimonial. Which I'm far better at than explaining the scientific properties of engine oil.

Post by **rguzz** » 12 Mar 2016, 21:18

I use a quart of oil in my Audi A6 every 1200 miles and that is considered normal use for that car, i.e. within normal healthy engine range. As someone already stated, it might be tough to improve on one quart per 3k miles of stop and start driving no matter what you do. I've had so many oil leaks in my Volvo I've never been able to truly determine oil consumption. Just did the oil cooler lines and am now leak free so I'm looking forward to using one quart per 3k miles travelled!

Post by **jreed** » 13 Mar 2016, 06:59

Everybody is going to have a different take on the oil recommendation, but I thought I'd add my experience in case it is of use in your situation... My '97 855 GLT (187k miles) was losing about 1L every 3-5k miles when I used Mobil 1 10W-30. I switched two years ago to Mobil 1 10W-30 High Mileage and the leakage rate went way down -- I'm generally not adding more than a 100-200 mL before the next 5K oil change.

Post by **misha** » 13 Mar 2016, 16:46

About synthetic vs mineral oil....
Bmw made a research with a 100k km in a car with synthetic oil and in other car also 100k km but with mineral oil.
After dismantling the engine in tiny pieces....neither engine had signs of wearing.

Think about it.