Tow Beast - synthetic vs conventional motor oil

[Catigale]

Im running Castrol 10W-40 conventional motor oil in the tow vehicle - 2002 VW Eurovan with VR6 200 HP motor, I change every 6 months and filter every other oil change.

Ive got 66,000 miles on it now - you can tell I dont drive much on my personal cars (only to airport and back once a week)

It uses no oil between changes.

We bought the Admiral a 2006 BMW X3 last summer and love it - it uses synthetic motor oil with one change per year/15000 miles whichever comes first.

Im thinking of switching the VDUB to the same synthetic - eliminates one oil change and also lets me use same spare oil of course.

For the gearheads like Paul and KMac...what is the ins/outs of switching a 66k motor from conventional to synthetic? Should I do it?

[Hardcrab]

The worst thing that could happen is the engine might develop leaks that are not present with conventional oil now.

I've understood that it provides no benefit to change over after 75,000 miles or so.
The engine is just to worn by that time.

It all depends on how long you intend this beast to give you service.

What I don't know is, if it leaks with synthetic oil, and you go back to dinosaur guts, will the leak stop?

I remember reading a story in an Air Force Driver mag years ago when Mobil 1 was first introduced.
Smokey Yunick wrote the article for the AF publication.

He used a brand new, zero miles, Chevy 454 on a dyno with Mobil 1.
He ran it the equiv of 75,000 miles as I recall.
After breakdown, he reported that the factory hone marks in the cylinders were still present, and the rod bearings could be repackaged and sold as new.
He opined that new engines should be driven at least 4-6,000 miles, (but less than 75,000 miles) so parts can wear in before switching to the synthetic oil

That one artilce sold me, and have used synthetic oil ever since in my vehicles.

[Paul S]

billions and billions of miles on cars with conventional oil with no problem.

When was the last time an engine failed due to the base oil used? I can't remember one, ever.

stick with conventional oil. IMO. cheap. it works. well.

once my mechanic put synthetic in my audi TT turbo quattro, lost a qt of oil in about 1000 mi. topped it off..another 1000 mi, another qt. next oil change went back to conventional, back to a qt in 4-5k mi (and 10,000 mi LOF interval with conventional oil) Only time, ever, i had synthetic in my cars..last time too.

yes synthetic may exploit any potential leak. but it won't MAKE a leak. switching back to conventional (yes it is safe to do so..contrary to popular belief) will make the leak go away if it didn't leak before synthetic is used.

My take, if a car requires it..use it.. otherwise I use whatever oil is on sale. Never had a problem with well over 1 million combined miles between all my cars (current and past) using conventional oil.

had my MG motor partially disassembled recently with 40k mi on a rebuild, looked like it just came out of the machine shop using conventional oil, still has 80# oil pressure. 110,000 on my other MG motor also still has 80# pressure and runs like a champ. 220,000 on my Accord, 190,000 on my pickup, 170,00 on my Land Rover, 110,000 on our Audi. all flawless motors, all on conventional oil.

Never seen any solid evidence that synthetic will extend the life of a motor, reduce maintenance, cost over a motor's useful life. Synthetic is not a bad product by any means.. I just don't buy into the hype..

Synthetic should be changed at the same interval as conventional oil. Part of the purpose of changing the oil, is the filter..and to remove impurities in the oil and drain it.

short answer: If want to try synthetic..go for it.. no downside. you can always go back if you want. I wouldn't make a habit of it though.

[Hamin' X]

At UPS, they did a five year evaluation of synthetic vs conventional oil. I think that they used three different synthetics and regular Delo 400 15W-40. We use Mack Cummins and Detroit diesel engines and put on between 175,000 to 200,000 miles/yr. The cost/benefit ratio came out on the side of conventional oil and no engines running synthetic oil were in better shape at the 1,000,000 mile rebuild. As well, the regular engine oil analysis done at the PMI intervals did not show any significantly less wear. Like nitrogen in the tires, I think it is more hype than benefit. YMMV.

~Rich

[Paul S]

At UPS, they did a five year evaluation of synthetic vs conventional oil. I think that they used three different synthetics and regular Delo 400 15W-40. We use Mack Cummins and Detroit diesel engines and put on between 175,000 to 200,000 miles/yr. The cost/benefit ratio came out on the side of conventional oil and no engines running synthetic oil were in better shape at the 1,000,000 mile rebuild. As well, the regular engine oil analysis done at the PMI intervals did not show any significantly less wear. Like nitrogen in the tires, I think it is more hype than benefit. YMMV.

~Rich

I would buy that. I think the issue is more of regular routine maintenance rather than the oil's base that is important.

But with the strong marketing and glam scientific looking lab experiments pushing the oils to extreme situations looks cool...but in the real world, I think if an engine will fail, it will be due to something OTHER than the oil base. lack of oil changes..missed timing belt change..etc

I do like nitrogen in my tires..as i get it free from Costco.. but won't pay for it.. sure it is technically better.. but it is not worth $80-100 the dealers are charging. Air works quite well.. i'll take it when its free, but won't go out of my way for it.

[Hardcrab]

No disagreements with the above.
After all, who runs a car 200-300,00 miles?
Other things start breaking before the engine goes south.

But synth brings more to the table than lubricating properties.

In my one, unscientific, empirical and therefore semi-useless personal experience, synth saved my bacon in a big way (IMHO):

1988 Ford Bronco
302 V-8
140,000 or so.
Mobil 1 after the first 5,000 miles.
25 miles deep in, easy 4 wheeling around in the mountains and valley dirt roads in the Mojave desert.
Summer.
Alone.


Noticed the temp gage rising.
Slight steam from under the hood.
Needle pegged.
Ugly, to say the least.
Decision time.
Let it cool for about twenty minutes.
Head back out on a wing and a prayer.
Before the paved state road is reached, the engine seizes and stops running 3 seperate times.
Let it cool some each time until it restarts.
Forget the consequences.
One more freeze up before the gas station and a water fill up for the final leg to home.
Decisions,decisions.

Forward in time:
Replace the leaking corroded freeze plug.
The final result?
No engine problems.
No smoking, no knocking, no nothing.
Still running fine for the next owner 4 years later.

Would conventional oil have left me with the same results?
Maybe, but I'll never know.

Or bet on it.

[dennisneal]

Who runs a car 200 - 300,000 miles?

Me.

We owned a 1985 Toyota Corolla and we got 325,000 miles from it before we finally sold it. Then we bought a 1995 Toyota Corolla and that one lasted for more than 250,000 miles. It was in excellent condition when we sold it in 2009. Today we own a 2006 Camry and a 2007 F-150. We buy them new and plan to keep them at least 10 years.

The secret? Regular maintenance: oil changes at the factory recommended mileage, etc., etc. I generally buy Castrol, or other premium oil like Valvoline, (but not synthetic).

I figure that an engine is just getting broken in at 75,000 miles.

[Paul S]

2-300,000 miles... more people than you think! I know I can't afford a new car every 5-10 years..If it is paid for.. I keep it!!

cars can go longer than people realize. people get new cars because they want a new car..not because they HAVE to have a new car. Unless there is a significant reason, 200,000 is the minimum number of miles I will keep a car. Most cars are taken from be from accidents than anything else. Then again, most cars with 200,000 and 10-15 years old will be pretty much a total loss in any moderate accident.

[Paul S]

No disagreements with the above.
After all, who runs a car 200-300,00 miles?
Other things start breaking before the engine goes south.

But synth brings more to the table than lubricating properties.

In my one, unscientific, empirical and therefore semi-useless personal experience, synth saved my bacon in a big way (IMHO):

1988 Ford Bronco
302 V-8
140,000 or so.
Mobil 1 after the first 5,000 miles.
25 miles deep in, easy 4 wheeling around in the mountains and valley dirt roads in the Mojave desert.
Summer.
Alone.

..........................
Would conventional oil have left me with the same results?
Maybe, but I'll never know.

Or bet on it.

My point is that conventional oil will not cause an engine to fail sooner than syn. oil under normal running conditions. When internal engine components fail, it is impossible to compare what one oil would do than another...

another, as you say, "unscientific, empirical and therefore semi-useless personal experience" . I had a head gasket replaced on my B when one leaked. This particular brand was not unidirectional. The mechanic put it down with the oil feed hole covered. The motor ran 100 miles with no lube getting to the head, other than any residue that might have been left on it. Once a pushrod failed, pulled the head. new gasket (put on right) and pushrod and we were good to go. Inspected everything else.. mechanic was amazed that no other damage was done. Got to love conventional oil!

But again in your and my case above, the oil base did not cause either issue. Yes synthetic has outstanding properties in the lab, but most people will run their motor without oil pressure, or something else and blow through that safety net (if any truely exists) and end up in the same pot.

Even if it has some magic properties, and it truely was the reason your truck made it back OK, it is still not a reason, IMO, for the average driver, in an average car, to use to extend the life of their motor. If a car overheats or runs low on oil, you pull over and call for assistance before damage can be done. Again, if it gives piece of mind.. go for it! Not trying to convert people to the conventional oil camp

[moondancer]

Hello All
I agree regular manitenance is the key in changing your oil. For the price of a filter thought I will replace it everytime I do an oil change. I find I break even price wise by using synthetic oil. I change it between 6000 and 7000 miles with filter, OEM filter. Saves me two hours and a possible mess in driveway once a year, time is priceless.
I worked with a guy who was a former mechanic on the old Barber-Saab series racing circuit. All their cars ran Mobil-1, they changed sponsors to another oil. All the cars blew their engines before the end of the season, except one. The other mechanics wondered why and the mech on this car amitted to pencil whipping the maintenance log. He never changed oil for almost two seasons. This was an unasked for testimonial. I now use it in almost everything, the Honda BF50 gets it this fall when I do the end of year maintenance.
It may be hype and may not but it doesn't cost me more than $20 extra at the end of the year.
Well that is my two cents, hope the season is going well for everyone.
Mike

[TAW02]

Typically this and any auto/truck/outboard/airboat/(insert here)/question about maintenance can be answered here :

http://www.magicmechanic.net/

These guys are terrific and also have a Saturday afternoon radio show you can listen and call in on toll free.

[Scott]

I also must admit, I am a fan of the Synth oil. I use it in everything. Albeit it out of laziness because my idea of an oil change is replacing what leaks out and I believe that synth oil retains its ability to lubricate over time better than normal oil.

That being said if you are a fan of regular oil changes, Dino oil is just as good in the short term.

[kmclemore]

Ditto here. I've used Mobil-1 in my cars for over 20 years now, and they all run beautifully... for example, I have over 170K miles now on my Dodge Caravan (tow car & Boy Scout vehicle), and trust me, I ride that truck very hard... and I tend to run 10K between changes.

However, one caveat... I do NOT use synthetics in my vintage cars. They were not designed for such oils, and when you introduce synthetics into older motors (with antiquated seal and gasket designs) they tend to begin leaking oil like a sieve. IMHO, use Dino oils in older cars (say, pre-1980) and use synthetics in newer ones (>1980).

[Scott]

OK, you caught me out. I do use Dino 20-50 in the MG. I didnt consider that one but only because I cant find 20-50 in Synth. That would be a good experiment. It uses about 1 quart every 2+ years. Due to lack of miles. I should switch it and see.

[grady]

Synthetic oil, does not break down as quick at conventional oil, but it does not suspend impurities as well as conventional oil. Piston engines dump a lot of trash into the oil.

Conventional oil breaks down quicker but suspends the impurities so they can be removed.

In my opinion synthetic is not the best choice for a piston engine. If you are racing and looking for best lubrication with the least resistance that is another story.

Now you can get the best of both worlds with a semi-synthetic oil if you are driving a lot and wanting extend you oil change interval.

Another reason to change the oil every 3 to 6 months on a low use engine is to remove moisture that builds up inside the engine. This happens when you do not drive for long periods of time and the engine does not stay at operating temperature for hours.

Oil discussions are so much fun, I do not think there are two opinions the same on it.

(as long as we are on oil, a fun question to ask. "What does the "W" stand for in an oil rating?" contrary to popular thought it is not Weight)
Think way back to before multi-viscosity oil.