17,350 miles on my 2k2...should i change to synthetic or just stay with the 10w-30. is it worth it?

 

Go synthetic, much better! BTW, I hope you made a mistake writing 10w30.......our cars, 02's anyway requires 5w30.

 

my mistake...

 

I know a lot of people are going to recommend Synthetic (I am not disagreeing with these people but offering my .02), but I have some feedback for you. As you know this debate will be around forever, so it's ultimately based on your personal preferences.

It depends what you want to accomplish by running synthetic: higher oil change intervals or getting 1.3 more hp from the lubricating advantages it offers.

If you are planning on changing your oil at higher mileage intervals, feel free to use synthetic. It does protect better than conventional type oils. Please note that at certain mileage during an oil change life, certain impurities get into the oil from normal driving, such as silica (from dirt ingested by air intake), other heavy metals from bearings, and other stuff depending on where you live. There is plenty of research that shows these impurities and their concentrations in the oil at certain mileage. What I am trying to say is that while the synthetic is protecting, your oil filter will determine how much of these impurities stay in your oil, meaning they are too small for the OEM filter to catch, but do cause harm to your engine.

Most of these impurities reach a critical level (meaning a level to cause harm) at or slightly before 4,500 miles. Of course this varies by location, and types of filters you are using (air and oil).

The whole point of this is no matter what type of oil you wish to use, the stuff that causes harm will get in to your oil anyway at certain mileage so you lose the benefit of increased change intervals. If you use conventional oil that's good quality, change it every 3k to 3.5k and use OEM filters, you will not have an oil related problem. If you are trying to get that extra 1.3 hp that synthetic will give you AND are willing to pay more for an oil change, have at it.

As mentioned above, most of the benefits of synthetic are lost after 4-5k miles into an oil change. I will try to find a link to the information I mentioned above and provide on another post. Or you can call direct to any major oil manufacturer (that make both types) and get some info. But you will need to ask for an engineer not some marketing type that gets more profit when they sell synthetic.

 

According to our huge oil analysis spreadsheet, your 4-5k oil change interval isn't correct. However, like you mentioned there are alot of variations that attribute to contaminents.

 

I appreciate that "Huge Oil Analysis" spreadsheet. But there are other sources of info which the guy asking the question needs to be made aware of.

I have not studied this spreadsheet in detail.

I have seen other studies, independent of oil type, that BASICALLY illustrate how various types of contaminants build up in oil over time (mileage) until they reach a point which contributes to an above normal level of engine wear. It is actually very interesting how some contaminants only begin to show up at certain mileage of oil change, clearly indicating engine wear. Because some of these cont. are materials such as piston rings are easily identified. Rings are different material than the bearings, and so on. Again, just my .02.

Synthetic is not a license to go 15k on oil changes.

 

Oh yeah, I change mine every 3000 to 3400 with 5w/30 conventional and a Nissan OEM filter.

 

I've also seen many studies showing much longer drain intervals with many types of oils and many different types of filters. The best thing about our spreadsheet is the fact that most of the entries are in Maximas.

 

One of the major benefit of synthetic as I understand it, is how much more quickly it flows at startup than regular non synthetic oil. Getting oil to critical engine parts is...well...critical, and it's here that a synthetic oil far surpasses a regular oil. If you live in a cold area of the country, try leaving a bottle of regular oil and a bottle of synthetic outside overnight and then watch how quickly synthetic pours out. I know which one I'd want on a cold winter morning. Synthetic also stands up to heat and viscosity breakdown better than regular. The extra hp, and extended mileage, in my mind, are just nice side benefits.

 

synthetic advocates in the industry push the higher change interval so that they can pursuade old joe to pay more for oil.

it's synthetic, it's better, it's cleaner.. no it's oil. all the few advantages it provides you destroy with the higher drain interval. be good to your car and change it at 5000, regardless of the oil, unlike that old joe with his diesel that changes it every 30k (yes i know such a person). don't worry he will trade it in next year.

 

Why not keep the standard change interval and use semi synthetic for the benefits. It's MUCH less expensive than full syn.

 

It all depends on your drain interval. Semi Syn seems like a waste of money to me. I usually change oil in the Durango either once or twice a year. I change the Maxima every 10k.

 

If you go synthetic, don't change your oil every 3k miles; waste of money.

I personally used regular Penzoil on my other car which was donated (tax break). I've had 300k+ miles on it and still ran fine.

 

BMW and the like recommend 15k for synthetic changes.

 

They also have 7+ quart oil capacity. That increased capacity offers a larger and longer buffer against contaminants. Personally, I use synthetic, and I don't go over 5K in my maxima. I went 7-8K in my 328.

 

I went 25k in the civic and sold it with 250k on the odometer. I sold it to a Honda mechanic who promptly tore the engine down a tad to see the damage. He now uses Amsoil

 

I change every 5k with Mobile 1 synthethic 10w-30. It is still fairly clean when coming out. I would not dare wait until 10k between changing times.

 

1) You cannot determine the oil's condition by looks. This fact has been discussed MANY times.
2) You can go 10k inbetween changes IF you are using the correct oil, correct oil filter changes and have the oil's condition analyized. (by a lab, not by your eyes)

I'd read some of the stickies because ALL of this has been discussed in great length more than once before.

 

If you have ever torn an engine down you would see that engine oil is on the engine parts that require lubrication. The so called "dry startup" is a phrase that is used to scare people into buying more product than they actually need. The oil that adheres to the parts will be sufficient to offer protection until the pressurized oil is delivered after startup. As long as you don't rev the engine too high, you should not worry about engine wear on startups. Just my 2 cents based on my experience as a mechanic.

 

Are you saying that, after my car has sat all night (or weekend or whatever) - longer than a few hours anyway - that there is still going to be oil adhering to parts in the upper regions of my engine? If it's -25 celsius out and my oil is too thick to flow to the top of the engine almost immediately, is this residual layer of oil going to be enough to protect the engine? I'm not a mechanic, and I've never torn down an engine, but I can read - so what of all the studies that show most engine wear occurs at startup? I'm not trying to be antagonistic here, just wondering since you've had the opportunity to see an engine or two dismantled.

 

Yes, that is exactly what I'm saying. The engines that I have torn down had been sitting for over a week and sometimes longer. When I disassembled them for overhaul, there is always oils on the moving parts of the upper engine. Adhesion is one of the properties of oil.

 

Yes there is oil BUT how do you know the existing oil film is strong enough to prevent metal to metal contact. Just because there is oil on the part, doesn't mean there is enough oil for adequate protection. Part of the oil pump's job is to keep enough oil pressure though the engine. Which keeps the oil film thick enough to protect the engine.

 

I can only tell you what I believe based on my experiences. All engines are not designed alike so one size does not fit all. We have an old Johne Deere 850 bulldozer where I work. A few years ago, an equipment operator drained the engine oil for an oil change. He started the engine, raised the blade and backed the dozer up so that he could clean up the work area he was in. After he backed up about 25 feet, he saw the drain pan with oil in it and remembered that he had not put any new oil in the engine. As he turned the ignition key off, the engine made a screeching sound. It had been running at high idle for over 1 minute by that time. When we tore the engine down for repair, there were only two crank bearings that had seized.
We had the crankshaft turned and just put new rod and main bearings on it to repair the engine. The oil in your oil gallery should do just fine until the oil pressure comes up as long as you don't go crazy with the RPMs. It takes less than 10 seconds for most oil pressure gauges to respond. Think about what happens when you change your oil and can't prefill the filter. Your engine is not unprotected as long as your oil pump is in good shape.

 

Don't know what you are getting at Charlie.
1) Bulldozer was only able to run for less than a min w/o oil. Although it ran that long, the damage started much earlier than 1 min.
2) Even though the oil pressure guage takes xx seconds to respond, the oil in the engine is circulating much faster. Even during an oil change.
3) The reason why engine's experience 90% of it's wear during startup is because there is not enough oil film to protect the engine for a split second between start/good oil pressure. With modern ecu/fi engines automatically going to high idle at start doesn't help things either.

 

I'm not here to argue with you Jeff. I'm just stating my opinion and experience and not believing all the hype about "dry startups." What is your experience with engine repair and diagnosis? What I was getting at is the oil adhering to the moving parts in your engine will protect it long enough for the pressurized oil to do it's job. How else could we get high mileage on some of our fleet vehicles without suffering any major engine wear or internal damage? I can see that we disagree on this subject but that's cool.

 

Mechanics is not my profession but I'm a very experienced in this field. I don't want to argue either so I'll just say the following opinions of mine.

The existing oil residue is merely adequate to lubricate the bearing surfaces until the oil pump gets the pressure up. The reason the engines live so long now is not really a function of oil sticking on metal(or else engines would have lasted a lot longer before). It's more of a function of better engine head design/modern FI and computer based engine electonics. We can agree on this.

But that doesn't change the fact that engines experience much of not most of their wear during startup(this is my belief anyway). Especially now that much of the other wear problems have been eliminated by the above. The way the car starts and get it's oil pressure up has not really changed in many years.

Now my arguement of oil film vs oil pressure is this. If the only criteria for keeping an engine properly lubricated is only keeping some oil on it's parts, there would be no real need for bearing clearances and oil pressure specfications.

I believe the wear concern of the other poster was synthetics flow much better in colder weather. So when you start the car on a cold morning, the engine can circulate oil much faster and get up to it's operating oil pressure faster. During extreme cold temps, I believe this time difference can be significant. But most of us don't drive in these extreme conditions that long. But that doesn't mean synthetics aren't superior in this regard and others(ie.. film strength, contaminate levels, additive packages, etc....)

In fact of superior film strength alone would be a good argument to use synthetics.

 

I believe that most engine wear is done when people leave dirty oil in the engine way too long. The abrasive action starts wearing machined surfaces once the softer bearing surfaces are worn. We have some 1988 Johne Deere motor graders that were torn down for overhaul when they were 13 years old. They don't use cam bearings in the engines. There was no wear on the cam journals or the engine block. The oil was changed on a 100 hour or 5 month interval. You may or may not get my point but I'd say that it spoke volumes about the manufacturing process and the use of conventional oil. What I understand about oil is that it has several functions. Preventing metal to metal contact is just one of them.
We have over 300 pieces of equipment in our fleet. It costs several thousand dollars just to buy conventional oil. The cost of synthetic would be a major drain on our maintenance budget. If you can get over 300k miles on a fleet truck using dino, there is no real justification for the bean counters to buy synthetics.

 

I agree with you. In order to go synthetics, you would have to subscribe to a long drain interval program with oil analysis. The only oil that touts that possibility is Amsoil.