_andross_

don't you change oil every 11,000 km for synthetic?

seanv98

If you run synthetic you should still change it every 5000k. If your waiting 'till 11 I hope your checking your oil level.

Bradsma

synthetic filters pick out small particles

MPR

The age and number of km's has nothing to do with whether you can use synthetic or not. Heck, you can even mix them (reg and syn oils). It doesn't matter. Oil is oil.

The difference is in the longevity of the oil, it's ability to withstand more extreme conditions without breaking down and it's ability to flow through tighter spaces/tolerances.

About filtration? The reason you can go longer even with a regular filter is because a lot of the crap that gets filtered out with regular oil is from the oil, itself, breaking down. Since regular oil will break down quicker, you need to change the oil and filter more often.

The reason it's questioned whether to switch to synthetic on an older, high mileage engine, and why some people stick with regular oil is because synthetic can flow through tighter spaces/tolerances much better. In a case where the valve seals are worn or if there was once before a minor oil leak, with synthetic, can appear to leak worse, because it can flow through that tight space better. In which case, the leak should be fixed anyways.

It is important to check your oil on a regular basis, regardless of what kind of oil you use. I usually check mine every 2-3 fuel fill-ups.

_andross_

wow thank you for your very informative post finally someone answered my question haha. So how often would I have to do an oil change? Still every 5000km?

MPR

It can vary depending on the condition of your engine. I'd check it on a regular basis and by 5000km's if you think it needs to be done, then do it.

In some cases where the engine may be in poor condition, where it has a lot of blow-by (piston rings are worn), and consumes oil, or has a knocking rod bearing, then yeah, you'd probably need to change it more often.

It's comon sense. Not every engine is the same. If you're using synthetic, by 5000km's if the oil still looks good, then there is no need to change it. The oil change interval is at your own discression. Some synthetics say right on the bottle "up to 15,000kms between oil changes" (or whatever), I wouldn't necessarily trust that for every engine, especially an older engine in not so good condition. It's hard to say exactly when to change it without knowing your car/engine intimately. (yeah I know that sounds funny but...). I usually go 10,000 between changes with mobil1 or amsoil full synthetic, and thats on my 2000 SiR b16a2 with over 220,000kms.

zeeman

iTrader: (1)

See when they say "up to 15,000kms" that means under perfect conditions, not harsh conditions. Harsh conditions being idling for long periods of time (like sitting in stop and go traffic), trips where the engine doesn't get to normal operating temperature (quick trips to the store and back), severe temperatures (below like -15 and above like +30 or so....which we see here in canada) etc etc etc.

Whats more important IMO is changing the oil/filter regularly and maintaining a full oil level between changes.

I've been using regular dino oil in my car since the day I got it. The engine in my car has a minimum of 250,000kms (I say that b/c I assume engines from importers have at least 100,000kms on them and i've put 150,000kms on it myself) and has been boosted for the last 2.5+ years. I daily drive this car year round and it sees its fair share of abuse (tracking, dyno time, etc).

I had aftermarket cams in my engine for like 80,000kms. When I pulled them out to sell them I couldn't believe the condition of them, they looked like cams with 10,000kms (or less) on them, as did the rocker arms and cam caps (bearings). Even the buyer commented on the condition of them, doubting that I used them for as long as I stated.

I've even seen a dyno test comparison of different oil brands. Believe it or not, the cheapest dino oil produced the highest numbers.

I personally am not a believer of synthetic oils and also believe that if our engines required synthetic oils Honda would use it from the factory, which they do not.

I'm tempted to send my oil off for an oil analysis when I'm done with it, this will show exactly if the oil is meeting your engines needs or not.

I'm not bashing people that use synthetic and i'm not saying that you shouldn't use it, i'm just stating my experiences with regular dino oil and how well it protects my boosted/modified engine.

R1020

iTrader: (1)

i agree with zeeman, it's the regularity of oil/filter changes and the maintaining of a full oil level that matters most.

i run castrol GTX 5w30 and OEM honda filters. i also run molybdenum disulfide in my oil (typically once every two years).

peter

gavin.p89

what is molybdenum disulfide?

civicef9

For people who say that you can double the amount of time on synthetic oil that is false statement. Oil is oil and breaks down at 5000kms, hence change oil every 5000kms/3months whichever one comes first. Sure enough you can run your oil for as long as you want for a fact run it til 10,000kms if you want, but remember the protection you get from oil additives (detergents, lubrication etc...) are all pretty much gone so you're hurting the engine more than benefiting. Even though from factory honda does say to change your oil at every 8000kms/6months that's because your car still has warranty so they can back themselves up if anything does go wrong. The main difference that you pay between syntheics and conventional oils are advantages. Conventional oil is meant more for stop and go driving meaning no beating your cars like crazy. Synthetics on the other hand means man made so what they do is take all the good additives from conventional oils like better gas mileage, better resistance between hold and cold weather, better start ups in hot and cold weather conditions etc. and leave out the unecessary additives and combine it into a better oil called synthetic oil. Also if you are burning extreme amounts of oil there is oil called higher mileage oil which is in fact conventional oil, but with an extra additive in it call ester which prevents burning of oil by swelling up seals to try and stop oil burning.

Hope this helps.

MPR

Fair enough. I've heard this over the years... that is, people using different types of oil with different experiences and results.

In my case I have seen nothing but improvement by using synthetic over regular oil in all my vehicles.