Synthetic oil in an 850 with 150K miles

We're coming from different places. I'm looking for a compelling reason

*not* to use synthetic oil.

It's pretty clear that synthetic oil - maybe especially Mobil

1 - is more likely to cause leaks in older engines that have been run on conventional oil. Japanese cars seem less prone to these leaks, and Volvos more prone to them. I don't know about American cars. If you drive a Volvo, the closest you will get to a consensus (not very close!) is that turbos and early model 850's will likely benefit, and it probably isn't worth the risk in the other Volvo engines. The same seems to apply to synthetic blends.

Regular oil changes with an oil that SH or current additives all you need to "keep the lifters from sticking". Synthetic oil in and by itself is not needed to prevent valves from sticking - and I have an 83 Volvo 240GL, an 83 Plymouth Voyager, a 96 Volvo 850, and a 1954 Case D tractor to illustrate my point.

Ken, Canada

I was referring to a specific, known issue with the first couple of years the Volvo 850 was produced. The oil passages in the head were/are very small, and for the first couple of years there is a fairly high rate of failure for the hydraulic lifters. But hey, this is usenet, so one has to expect gratuitous abuse!

The one reason not to use it is the added expense with no real benefit.

I am looking for one reason to use it. Sure, it tests better in the lab, but no one has translated this to real world benefits. Not one.

No one has mentioned that Volvo has permitted synthetic oils to be used in its cars made in 1981 and later if they meet the API Service specs listed by Volvo which in 1981 were SE-CC and SF-CC. However, Volvo has never recommended synthetic oils.

This is per the owners manuals which are available on line.

I use synthetic because it flows better when cold - keep a bottle of regular oil outside in the winter, beside a bottle of synthetic. My synthetic 5W40 gurgles when I shake the bottle at my typical winter temperatures, whereas the bottle of regular 5W30 does not.

Synthetic also has higher heat resistance, so in my turbocharged cars, and air-cooled motorcycle, snow blower and lawnmower this higher heat resistance makes me feel like I'm protecting them better, even if regular oil has enough heat resistance for the temperatures reached.

So there's 2 reasons - better protection when cold and easier cold starts, and it makes me feel like I'm doing something for high temperature protection.

Synthetic oil is subjected to higher quality control standards; how's that for a benefit?

I am looking for a reason not to use it. Sure it is met with skepticism, but on one has translated this to real world risks. Not one.

People can actually substantiate this, reporting leaks on their Volvo motors, clearly caused by switching to synthetic oil?

Just how "clear" is it, and where are the data? Is it "clear" enough for a class action suit?

There is a Mechanical Engineer in Bath, Maine who has rebuilt many Volvo D24T engines. His experience with Mobil-1 in these engines after an overhaul (using a 40,000 mile oil and filter change interval) is that after 100,000 miles of operation there is _no measurable wear_. I assume that his observations include crankshaft bearings and pistons/cylinders, cam shaft and valve guides. If you want more details, please let me know, and i will ask him.

Based on his observations i switched my 1989 Volvo 240 Sedan (250,000 km) to Mobil-1 about 5 years ago. I have seen _no_ evidence of leaking seals. My son's 1986 Volvo 240 Wagon (465,000 km) likewise received Mobil-1 about 4 years ago. There has been _no_ sign of oil leaks. I changed the timing belt a month ago, and did not bother replacing the three front oil seals as everything was completely oil free and dry. The oil consumption of this engine was about 1 liter/1000 km. With Mobil-1 it is down to 1/4 liter/1000 km. I recently changed the oil after 40,000 km, and it was quite clean. More importantly, i also checked the throttle body (TB). It was also clean. Before the change to Mobil-1, i removed the TB and had to clean out a lot of gummy, brown deposit.

In my experience, Mobil-1 is a superior product. The ability of the oil to cling to metal surfaces better than conventional dyno oil is an advantage during engine startups. Less wear will be the result. Remember that startups cause a lot of the wear in an engine.

Do a search in this newsgroup. You will see a pattern of people buying a Volvo, - usually a 240 - switching it to synthetic because they want the best oil for it, and then getting leaking seals. It happened to me and to many others. I still recommend synthetic oil for the 850 with its hydraulic lifters and small oil passages, and for turbo engines, but for normally aspirated Volvo engines it doesn't seem to be worth the risk of leaks. No, not enough hard data for a class-action lawsuit, just years of observations, and personal experience. You can believe me or not, as you like. I won't have to buy you any oil seals. ;-)

Correlation is not causation, but strong evidence that these oils that are being heavily marketed to consumers for use in their high-mileage engines, would be interesting to confront the oil companies with.

I also wonder this: Are seals worse than rings and cams?

There is no evidence that non-synthetic oils, used as directed and changed regularly, cause excessive wear. The one study I looked at showed the opposite: that in NYC taxi cabs, synthetic and non-synthetic oils performed the same. As others have noted, synthetic should provide better protection in extreme temps, but for normal driving - and especially in Volvo red block engines - you will see little or no difference in wear.

But enough of this. No one's mind is going to change.

I drive in an environment that routinely sees extremely high temperatures. This subject is genuinely of interest to me.

People keep coming back to a conservative argument in favor of old-fashioned oil, that smells like what we call in the IT industry, "FUD."

I believe you when you suggest there is nothing wrong with standard lubricants. I'm not trying to suggest that there needs to be a

*problem* with them in order for synthetics to have merit. And I don't see synthetics as particularly expensive, either.

According to your data, synthetic oil performs at least as well as standard, and no specific problems have been attributed to its use, aside from anecdotal reports of seal failure.

Use only fully synthetic as the mixes are a rip off .REAL synthetic means a clean engine no gunk build up and longer life for the engine ,as for a turbo its a must .The original synthetic did not have elastasizers in it which swell the seals slightly, now this is ADDED the oil is brilliant .With synthetic you need not change the oil as often so in this way you save on the higher costs JUST CHANGE THE FILTER AS USUAL .No doubt your engine is now cleaned out of all the rubbish and scum that dino oils create. Be patient and you will find all is ok.Provided you don't use castrol which many say is just a highly modified dino oil .I use Mobil one or Bp visco

5000. My neighbour changed to synthetic oil Mobil one and I did the change all was well till she went to the mechanic with a new container of Mobil one to put in the car he switched oils and you could feel the difference .HE HAD HER SYNTHETIC OIL STILL ON HIS SHELF IN THE WORKSHOP .

I disolves buildups and makes gaskets and seals more vulnerable to leaking. Anything good at lubricating is good at leaking. There is a compromise there someplace. That is the reason for different viscosities and grades.