mscir

I have a 2001 Civic EX with 110,000 miles on it. It uses a bit of oil but doesn't leak any. Is it too late to switch to synthetic. I read about doing that a while ago but wanted to check in and see what you guys had to say about it. If I understood what I read, not having used synthetic, there may be dirt deposits sitting on seals preventing the rubber in the seals from getting exposed to oil in places, the deposits of dirt can lead to the seal drying out. Synthetic has far more detergent so it washes the dirt away, and the dry seals will crack when flexed, causing a leak. Is this a correct understanding of why a car with 100k mi. should not change to synthetic oil and what causes the leaks when someone does?
Thanks,
Mike

Creager

I have a 2003 Civic EX with 220,000 miles on it. It doesn't use or leak any oil.

I've only used Castrol GTX 5w-20, for no reason other then i like the label and it was on sale once. It is conventional oil. I change it every 3,000 miles. The reality is, I could probably go a couple thousand more miles between changes.

That's what you pay for when you purchase quality synthetic oils. The oil isn't formulated to turn the inside of your engine into a dishwasher, instead its to prevent the oil additives from breaking down. Thus, providing you with a slew of benefits including allowing more miles between oil changes.

The only way you can know for sure if it's right for you, is to try it and have an oil analysis performed by a lab. They will be able to tell you exactly how much additive is left in the oil, what trace materials they find, the likely source of these metals, and how long to go between oil changes with that specific oil

Otherwise, if you got dirt in your engine, you got bigger problems.

mscir

I don't see any evidence of dirt in my engine, I was trying to explain what I read. Thanks for your reply.

EarthAbettor

I recently purchased a 2004 Honda Civic and just put in synthetic oil and so far no problems with leakage. There may have been synthetic oil in it before though. It is Eneos oil though I've heard Valvaline and PENNZOIL PLATINUM HIGH MILEAGE and VALVOLINE® FULL SYNTHETIC WITH MAXLIFE TECHNOLOGY MOTOR OIL. They are full synthetic but designed for high-mileage cars supposively. Has anyone used them?

alex_nyc

I think I read somewhere that it you switch to synthetic at a high millage the engine will make more noise such as valve train noise due to the new oil being so thin as the engine has wear at high millage.

The other thought is, how much old oil is left behind when you drain the oil? When you switch to synthetic oil, its now mixed with regular oil? Is this mixing of synthetic & used dinosaur oil a good idea? or maybe you should try a synthetic blend instead of a full synthetic product?

Dinosaur oil is good enough for me! at 120k miles -so far so good! -dont fix what aint Broken!

pjb3

If anything synthetic oil should cause less mechanical noise. The thickness of the oil depends on the weight you use. Also, synthetic does not change viscosity or changes very little while dino tends to get thinner as the VI additives are used up.

Mixing dino and synthetic is not a problem since that is basically what a blend is.

alex_nyc

I dont think this is at all correct!

Plus -mixing oils yourself was always a problem!

mikey1

IMO a big waste of money,

your chances of an oil related failure on these engines in next to zero,

your body and frame will rust away to dust before you need to worry about an oil related issue, unless it is user error and you let it run low