Bad engine oil, is there such a thing?

I know that this topic has been written, hashed, fought over, and opinionated thousands of times on this forum and others across the net. This thread isn't to see what type of oil is the best oil to use in our bikes. We all know, that according to the topics on this forum under "oil", there are 10-20 "oils with great results".

My question is from a different angle; does anyone have any experience with an engine failure that can directly be attributed to the engine oil? Obviously there are stories of engines melting down but then the truth comes out that the owner changed the oil perhaps two years ago? Or was it three? And it was one quart low at that! I'm not talking about the folks that do nothing in the form of maintanance with their bikes. I'm looking for stories of people that do great mainanance on their bikes; change the oil every two or three rides, change the filter very often, check the oil levels daily, etc. But then the engine does fail or prematurely wear out because of the type of oil that they put in the crank case.

The reason I ask this is I've got a 1995 XR250R that has approximately 1000 hours on the bike. If during those 1000 hours the bike averaged 20 miles per hour, thats 20,000 miles! Most of those miles have been done by a teenager that raps the engine too fast, rides it during the heat of the day in the desert, loves to hill climb getting the engine hot, etc. The only oil this bike has ever tasted is Pennzoil 20W-50. However, one of the things that we do is change the oil every two to three rides. Change the filter every oil change. And we check the levels daily. We never have to add oil between changes and the bike still runs great. In fact, this bike will probably be passed on to the sister when she is tall enough to touch the ground.

There are studies that show that certain oils break down faster than others, cause clutch slippage, etc. But are there oils that can be documented to cause engine failures in motorcycles even with great maintanance schedules? Oils regardless of their makeup? I.E. synthetic, blends, dino, recycled, etc?

When we change the oil on a regular basis, every two or three rides like most seem to do on this forum. Perhaps there are many oils that will work with "great results". From the Mobil 1 to regular Pennzoil. I don't have an axe to grind nor a point to make. I'm just curious. I've never had an engine fail nor wear out because of the kind of oil that I used. Thanks folks.

You bring up a good point Copperglobe. Maybe we worry to much about the type of oil, instead of the frequency of change. I've yet to "blow" an engine, but like you, I change my oil every third or fourth tank. Never it let it get black, and you can aways be on the attack, that's what I say!

WR400 (me)

KLX300 (son)

KLX250 (wife)

XR50 (daughter)

XR100 (waiting...)

Four-Trac 300 4-sheeler (everyone)

At a shop I used to work at a long time ago as a kid while pumping gas, I used to hear the mechanics talking about Quaker State Sludge problems. I remember seeing engines torn down that were filled with sludge and I can still hear the mechanics saying how bad Quaker State oil was. Since then, I've heard the term Quaker State Sludge from other people and that always left me wondering if there were problems with that product or not. Now whether or not the problem was related to the oil was beyond me back then, but the mechanics where I worked sure thought so. In anycase, this was a few decades ago and things have changed considerably since then, but I still stay away from Quaker State products even though they are probably very good.

I really don't think you'll find a bad motor oil on the market today from a major company, so as long as you change your oil and filter in a timely manner you should be fine, but I do feel some oils are better than others.


I was one of those people that paid the higher prices for the best oil I could buy, up to 8.50 a quart, it would be Torco or Golden Spec, and so on, and one day I threw in the towel, now I buy just one oil, it's Honda's GN-4, and it's because of the price, 2.80 a quart, I will pay that but thats all and it's for all my bike, two! stroke trans and all 4 storkes. After I change it I always look at the oil carefully, and it all looks the same, and the shifts and runs the same. And last week there was a post about GN-4 that it was joke, but I've had good luck with it. :)

[ May 16, 2002: Message edited by: Turner ]

In the late ‘60s, the Honda dealer I was working for sent me to a mechanics school put on by factory representatives and one of them made a statement that I’ll never forget. “The only time you have clean oil is right after you change it.” This seems obvious but the point was to change it often. All oil related problems I have seen personally were from contaminated or worn out oil. Another friend manages a truck shop that maintains a large fleet of miscellaneous vehicles. He observed me changing oil at short intervals and remarked that I was draining good oil out of them. Yeah, well, I’d rather drain good oil out of them then bad oil. I heard the sludge build up story but is was Pennzoil instead of Quaker State. That story was from my cousin that owned a service station for 30 years. I avoided Pennzoil. The sludged units were probably neglected and would have had the sludge no matter what brand of oil. As long as you run the grade and quality specified by the manufacturer and change it often it probably doesn’t make much difference. That said I use Mobil 1 products including ATF and gear lube. I also have two trucks with over 200,000 miles and the motors are absolutely clean inside with no noticeable wear that ran Delo 400.


As I said, I'm sure there are oils that are better than others. But is it over-kill to put in the most expensive oil we can find? I've seen motorcycle grade oils that sell for $15.00 per quart! Is that oil better than the $1.80 oil for our bikes since we are changing it every couple tanks of gas anyway?

If we were to list all of the oils on the planet from the very best to the very worst for motorcycles, top to bottom. Where could we draw a line indicating that all the oils listed above the line are fine in bikes while all the oils below the line are not good for bikes? For us that take care of our machines, is that line a lot lower than we think?

I think I've got too much spare time on my hands! :)

Heard same sludge story here only it was supposed to have been Valvoline. All the sludge, regardless of brand, is pure neglect. Ran Valvoline 20-50 Racing in my '85 XR350, it's still going strong, but always changed oil before it got dirty. More than likely with the new refining technology we have now most oils are better than they were back then.

Most of the sludge stories come from the days before "detergent oils". Sometime in the '60s to early '70s the API upped the standard and the oil companies started using detergents to keep the sludge down in engines. There were many many older engines that blew up because the new oils would break loose old sludge and clog an oil passage causing a bearing to burn or other bad things.

With the new API SG to SJ oils the only real problem that I have heard regarding thier use in motorcycles is Honda put out a general warning about oils that used Molybedenum as a "friction modifier". The warning is for bikes with a wet clutch because the Moly can cause the clutch to slip.

Motorcycle Consumer News did a 3 part article (Aug - Nov '00) that did a bunch of oil chemestry and wear tests in a bunch of Gold Wings. The article pretty much showed that all the oils tested (32 flavors) worked well and were fairly close overall. But they did list the ones that they tested that used Moly, and listed the Parts Per Million (PPM) content.

Here they are:

Castrol GTX (auto) - 59

Castrol Motorcycle - 129

Castrol Syn-Blend - 114

ELF - 20

Honda HP4 (the one labeled with Moly) - 670

Redline - 872

Torco MPZ 100% - 626

Torco MPZ t-4r Blend - 736

All the others tested like Mobil 1 (auto & bike), Bel Ray, Golden Spec, Motul, Silkoline, Maxum, etc. had either zero or only trace amounts that were treated as testing errors.

Hope this information helps.

I'm putting my faith in Honda's GN4 20W50. Two quarts of it for my XR400, two and a half for my 650, (and a new Honda filter), every 200 miles. I've done this from day one with both bikes and the oil stays so clean in them that it's hard to see it on the dipstick. If I ever have an oil related engine failure I guess I'll chalk it up as a live-and-learn life experience that I should have run a synthetic motor oil. But until such time, I'll keep doing what I'm doing.

I run Torco conventional oil and change it and the filter every 200 miles. I ride all the time and my bike has loads of miles on it without fail. It is a 93 and has never been rebuilt and still runs strong. I am not convinced that synthetic is necessary with frequent changes, though it may be useful for those who do not maintain their bikes regularly. Well off to change my oil for China Hat next weekend.

Later, Ryan

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now