I have a 1995 850 wagon with about 160K miles. At about 150K miles, a mechanic in a local repair shop recommended I switch to synthetic oil because of the age and mileage on the vehicle. I did start to use synthetic and have since change the oil 3 times (i.e. every 3000 miles). I now see oil stains on the garage floor. Several thread in this newsgroup mention that synthetic oil can cause leaks in older cars. If the synthetic oil is causing my apparent leak, will changing back to regular oil stop the leak?
What is it about synthetic that causes the leak in older cars?
It's the high-detergent action, which dissolves varnish and sludge on seals, and sometimes the seals themselves, if the rubber isn't compatible. The usual approach is to replace all the affected seals, but you could try removing the synthetic oil and switching to 'high mileage' oil, which will cause the seals to swell. This may or may not fix the problem, but if it does it probably won't be a permanent fix. If you plan to keep the car, then since the damage is already done you may want to spring for new oil seals and then keep using synthetic - it should prevent the lifters from sticking, anyway.
Go back to conventional oil, preferably one of the high mileage formulations like Valvoline MaxLife, Castrol High Mileage, etc.
I used to think that this was an old wives tale, but I have seen the problem myself when trying to put synthetic oils, especially Mobil-1, into older vehicles.
Synthetic oil is an excellent way for the poor (ha ha) oil companies to extract money from our fat (ha ha) wallets. There is no documented evidence that cars that use it have any better reliability. Sure it is better, but replacing all the copper wiring with gold is better also. But the bottom line is are there any real benefits. So far there are none and as has been mentioned here there are many problems. Following the manufacturers recommendations is all that is necessary, in fact is more than necessary.
I would be interrested in your data source used for this conclusion. I would have thought that the higher "breakdown temperature" of synthetic oil would have been particularly beneficial for turbos, as the oil would not tend to coke on the high speed - high temperature bearings.
Thanks in advance for any data sources you can provide.
You missed the point of my post. Synthetic oil is sold on the basis of laboratory tests. It is never sold on the basis of real world use in cars. Sure people say that they used it and had no problems, but I can say that about using the factory recommended oils, filters and changes. The truth is there is no field data supporting the use of synthetic oil based upon and A/B comparison with manufacturer recommended maintenance. None. If they had it they would use it unless it wasn't favorable.
If you don't want oil to coke, then use non-coking oil like used in motorcycles. Cars don't need it. I use it in my garden tractor since, like a motorcycle, it is an air cooled engine. If I don't use non-coking oil in my garden tractor, the oil is like tar when I drain it.
You want some real-world support? I am the original owner of a 1986 Honda Civic Si. This 1.5 liter engine, and the one after it, both have a reputation for starting to burn serious oil after about 120k miles, even with regular valve adjustment. I've run it mostly on synthetic since it was broken in, and while I get a puff of blue smoke from draindown past the valve seals if I let it sit for a few days, it doesn't use an appreciable amount of oil, and doesn't produce blue smoke while running. It has about
143k miles on it. Not enough? I also have an '81 Suzuki GS850 that I've owned since '89, and I use full synthetic in that. Aside from doing a gasket replacement because of weeping (not seriously leaking) oil about 15 years ago, the bike also uses no oil at 25 years old and 26k miles. Both engines have been run very hard on occasion, although not that much in later years.
I'm hardly a die-hard synthetic oil fan, especially for Volvo Red Block engines - I usually tell people to avoid it. But that isn't the same as saying that it has no benefits when used from the beginning.
These are anecdotal stories and don't prove a thing. I drive my Volvos
175,000 mile now and never have a puff of smoke or any oil usage and I just use the Volvo recommended oils, filters, and intervals (which are
7,500 miles and 10,000 miles. But neither of us is proving anything.
A laboratory comparison would take identical vehicles and run them to death under identical conditions using the recommended changes and filters. This would prove something, but anecdotal stories are just that. In order to justify the use of synthetic oil, it needs to either provide longer engine life or provide the same engine life with extended change intervals. It has not been shown to do either.
Personally I am sold on synthetics for turbo charged cars, cars which see very cold temperatures and cars which see very high temperatures. Also for engine designs where sludge has been an issue such as certain Toyotas.
Because of its high electrical conductivity and resistance to corrosion and other desirable combinations of physical and chemical properties, gold emerged in the late 20th century as an essential industrial metal, particularly as a thin plating on electrical card contacts and connectors. Relays that are for high currents have silver contacts and those for low voltages have gold contacts. Many micro-chips use gold internal wiring for its conductivity on very small cross-sections. The most common choices are aluminum and gold and gold is superior.
Electrical resistivity are room temperature:
Aluminum: 26.50 nano-ohms per meter Gold: 22.14 nano-ohms per meter Copper: 16.78 nano-ohms per meter Silver: 15.87 nano-ohms per meter
So for precise instruments, gold is superior because of its very low contact resistance.
For high current applications, silver is superior because of its high conductivity and moderate contact resistance.
Copper and aluminum are not useable unless the connectors are exotic (not copper or aluminum) or the ends are plated. We all know about the problems of aluminum house wiring and copper is not a lot better.
If you are using synthetic oil on an engine designed for conventional oil, you are changing the operation of the engine. Synthetic oils have smaller molecules than conventional motor oils. This means that it is not compatible with some engine designs. If the manufacturer doesn't recommend it, you use it at your own risk. If engines last perfectly well with conventional oil, there is no incentive to take this risk.
The only pros are lower cost and less chance of leaks developing in the future. The risk of leaks depends on how long you're been using synthetic or syn blend; if a short time, then the risk of leaks developing is higher than if you've been using it for years.
Well presented - I'll give you that, but it does not establish a case for the use of gold wires! Contacts, yes, wires - copper is far better, cheaper and lighter, as your own numbers amply demonstrate!
There's good evidence that synthetic oil is superior to conventional oil in some ways. But what Stephen has been saying (I think) is that no-one has proved that these properties lead to longer engine life, on average, than conventional oil would in the same make of engine under identical usage conditions. As far as I know, no such tests have been done . . . but if they have, I hope someone will post a link or reference.
The pro is saving money. As far as the cons, who knows. Synthetic blend is really a poorly defined term and many "conventional" oils could call themselves a blend if they wanted to. In fact, the Connoco line of oils (sold as Union 76, Phillips 66, Connoco and Motorcraft) are all labeled synthetic blend.
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