I just bought a 2013 Volkswagen Jetta with 67,000 miles. It had synthetic oil in it and I was told I did not need to change my oil as often as I had been with my corolla. Why is that? I thought one of the main reasons for changing oil was because of the fine particles that build up in the oil and can damage the engine because they are so abrasive. How does synthetic oil prevent that? Won’t there still be a build up of little particles that shouldn’t be there?
Ignore whoever told you that. Follow the manufacturer’s oil change schedule in the users manual in the glovebox, synthetic or not.
And note that the recommended change interval is in the form of xxxk miles or xxx months whichever occurs first.
And I’d get it changed ASAP as the previous owner may have neglected it. Also check for other recommended maintenance that may be overdue.
1 Like
I haven’t been aware that accumulated abrasive particles were a problem in engines other than when faulty filters are involved. Oil fails when it deteriorates from heat and chemical contamination. The higher flash point of synthetics and eliminates one of the most significant sources of contamination in an engine with good compression.
Air cooled VWs were the last automobile engines I am aware of that were subject to accumulated abrasive particles. The only oil filter was a ring of window screen wire that prevented rocks and socket wrenches from being sucked into the oil pump.
5 Likes
Volkswagen oils have more additives and for that reason may go somewhat longer between intervals. Europeans love long drain intervals, regardless of what it does to their engine life.
As mentioned, observe the manual and make sure you put in the right oil; it will be much more expensive than what you are used to putting in your Corolla.
The oil filter is what removes particles from the circulating oil.
One source of particles is the incoming air. Make sure your air filter and the gaskets in its housing are airtight.
Detergent oils hold the particles in suspension and I assume synthetic oil is a detergent oil. Tom McCahill, in his book “What You Should Know About Cars” published in the early 1960s, had no use for detergent oil. He didn’t like the particles being whipped through the engine bearings. He preferred a non-detergent oil where the particles settled to the bottom of.the oil pan.
My first car, a 1947 Pontiac did not have an oil filter. It was made before detergent oils were common. My 1955 Pontiac also did not have an oil filter. However, it had hydraulic tappets and detergent oil was required. I had all kinds of problems with the oil passages sludging up, even after I added an oil filter. The engine had been overhauled just before I bought the car. Apparently, not all the sludge was purged from the engine. GM must have realized that detergent oils and no filter was a problem. The 1956 Pontiac and the 1956 Chevrolet V-8 came with oil filters as standard equipment, where the newly introduced OHV V-8 engines for 1955 on the Pontiac and Chevrolet had the oil filter as an option.
At any rate, I don’t agree with Tom McCahill on this issue.
You need to change the oil as often as VW recommends you do so. If your Jetta has a larger sump that your old Corolla, then that is one reason why it might not need oil changes as frequently as the Corolla. You can change the oil more often if you want to. That will cost you a little more money, and it helps you sleep at night, the cost is small.
1 Like
LOL!
That is the best description I have ever heard regarding the…“oil filter”…in those air-cooled VW engines.
Thanks for the chuckle, Rod.
Yes, particles can build up in the engine oil. Those particles can be due to inhaled dust, combustion chamber particulates, acids, and so on. NO oil filter made will remove all of those from circulating engine oil as generally speaking anything from 20-25 microns on down will continue to circle.
As for the air-cooled VWs a toilet paper filter kit was offered… 
1 Like
Agree on the VW filters , I had a 71 bus and after the first time I changed the oil, I never bothered to access the screen and replace the gasket. I just removed the small bold in the center and changed the oil every 3000 miles. While the oil was out I popped the valve covers and adjusted the valves. The valve seats rept recessing into the heads because I could not make myself keep the speed down to the 68 mph VW recommended.
The removal of particulate matter is the reason for an oil filter, there is no other mechanism for removal of particulate matter or abrasive particles.
Oil is exposed to combustion byproducts like carbon residue on cylinder walls. Will the crud, carbon, ash be more or less with Dino oil vs synthetic oil? Folks use that argument for trans oil. It does not experience combustion contamination so it should last the life of car? Right.
And todays filters seem to be 99% effective.
Anyone besides me remember the porous bronze oil filters that were advertised in the mid 1950s in publications like Popular Mechanics and Mechanix Illustrated? These special filters were supposed to remove particles much smaller than regular filters. These porous bronze filters were.cleaned in solvent at each oil change and reused.
I don’t recall bronze oil filters but GM did use a bronze fuel filter insert for several years.
And although the brand name escapes me I recall an oil filter that used a porous molded element similar in appearence to gas heater grates. Of course who these days knows what a gas heater grate is?
The Franz toilet paper filter was a strange device and I can’t imagine how one could be installed on an air cooled VW, @ok4450. But then there were centrifugal oil purifiers available for a while.
My recollection is that, in the early '50s, Pontiac used some sort of internal centrifugal oil separator/filter, before they began using cartridge oil filters.
I don’t remember whether this was on their six cylinder engine or on their straight eight, but I am confident that Triedaq–who owned an early '50s Pontiac–will recall the details.
@VDCdriver. I am not sure I remember much about this, but it seems to me.that both the Pontiac inline side valve 6 and 8 had some sort of oil separator in the pan in addition to the oil pump. I know that these engines did not have an oil filter.
Chrysler products of the 1940s and.early 1950s did have a.full flow oil filters on the. Inline 6 and the inline 8 flathead engines. . The inline flathead 8 was used in the Chrysler senior models, the Saratoga, New Yorker and Imperial model through 1950.
GM didn’t fit its Pontiac flatheads with oil filters. In fact the oil filter was an option in 1955 on its newly introduced OHV V-8 which replaced both the flathead 6 and 8.
I’ll try to remember more about the oiling systems used.on these old.Pontiac engines.
The oil filter was available as an “accessory” . Our 1941 family Chevy stove bolt 6 had a bypass oil filter in a canister on the side of the engine… You changed out the cartridge with each oil change.
Similarly my 1948 “green Hornet” Chevy Deluxe also had one of those bypass oil filters. Changing the cartridge was messy. In 1955 the new Chevy V8 had a “full flow” oil filter, which meant that more oil was pumped through the filter.
I believe the full flow oil filter on the 1955 Chevy V-8 was an option, but I would bet that most 1955 Chevy V-8s had that option.
Honda used centrifugal sludge traps on their old air cooled twin motorcycle engines.
