Can I put an oil cooler on my bike?

[gusmanxtr]

Hello, I've got an air cooled 250 bike and the engine oil goes a dark shitty looking colour pretty quickly after changing it. Does anyone know if an oil cooler can be fitted to any air cooled engine and if this may help the oil stay fresher looking for longer? Thanks in advance, Gus.

[Krasi]

In general, you can install oil cooler to any engine. Depends how "bolt-on" are the kits for a particular (engine) model. Otherwise you'd need more fiddling and "machining" to make it work.

As for oil color, that shouldn't bother you too much. PROVIDED, that your compression is OK, i.e. there's no blow by the piston. If the compression is normal, than the oil is doing it's job properly, part of which is to "wash" the engine from the inside.

[MC Pono]

Can you define, "pretty quickly?" Can you also state the bike you have, how many km, any service done to the engine?

Most likely if this is an old engine you are just going to have to deal with it, your oil being black isn't harmful because of color, it's the oil breaking down and other materials being introduced that are.

There are a couple reasons it could be going dark. None of which are detrimental short term.

First step is drain a bit of oil onto a piece of clean paper and let it soak through. Are there any particles left on the paper? If yes, then you most likely need to change your oil filter, or even install one if you don't have one. YOU DON"T NEED AN OIL COOLER.

Additionally:

What you may need to do is replace your valve seals and or other gaskets. It's possible that your engine is letting some air get in and that is sucking more gas into the engine. This burns, adds more carbon and makes your oil black.

It doesn't take much for your oil to be black in color. Most likely your bike is older, and its not a bike that is serviced like a race bike. In which case there's natural buildup inside that unless you get in and clean everything internally..you are going to have carbon deposits leftover that will get right back in your oil.

[spencer2004]

For just about any engine it is possible to install an oil cooler by tapping in to the oil filter, unless if there is a kit made specifically for your bike it will have to be a custom job. There are kits for sale pretty cheaply on eBay which includes the radiator, hoses, washers and banjo connectors but you would probably need some additional parts and mods will be need to be made to the oil filter cover.

As an example I figured that on my engine I can block off the return path of my oil filter, drill and tap a hole in the oil filter cover and attach a hose to it with a banjo connector, this then goes in and out of the radiator and returns to the engine through an unused hole on the side where there is low oil pressure. In total all the parts I need cost roughly £50.

It probably is worth doing as it would increase the life of your engine, increase the time required between oil changes and reduce the risk of overheating. On the other hand however it's one more thing to go wrong and it's only worth attempting if you are comfortable with doing this kind of custom DIY job.

[Evil Ai!]

Seriously - oil coolers and the hysteria surrounding them are MOSTLY bullshit.

If the designers are half way smart, they won't be designing a motor that cooks really easialy in it's own juices.

About the ONLY time you really need additional cooling is if your stuck in bumper to bumper traffic and it's getting towards 40*C - or higher....

Oils really are designed to go to 135 - 140*C or higher as they wash over hot parts, which also boils out the sulphuric acid at 127*C.. (never mind the additives).

Personally I think one is better off adding a combination small boiling water tank and food cooker to their engine and stopping for a regular cup of tea and a hot meal.

If you live in a hot place - and I don't mean like England where they all start dropping dead in a heat wave at 22*C.... I mean like in most of Australia, and other places where it's getting to 40 - 45*C or higher - regularly, and you have long trips to make at a decent speed... THEN measure your peak oil temperature, ask the oil company techs about this - and if really necessary - add an oil cooler...

People seem to freak out too much when the motor is hotter than a decent dinner.... surer the temperature is not unlimited, but it's generally much higher than the "OH my god - you can radically shorten your engine life if your engine gets too hot" - which coincidentally, is written by people who while they do have a genuine point, they are using that point as a general "all encompassing" statement, in the marketing spiel for their oil coolers, that they are trying to convince you that you need, and must buy.

Yes - I would use one if I was racing across the Sahara desert - mid summer.... Yes I would use one on a transmission - IF I was towing a large van on hot days up big hills.... Yes I would use one if I was riding in stop start traffic on very hot days... or travelling fast on hot days...

I think for the bumper to bumper traffic, there is much to be said for using some silicone sealant and gluing a couple of ceramic bearing computer fans to each side of the cylinder.

Or adding a couple of computer finned heats sink to the rocker cover or engine cases, or some other method of dumping the heat.

[spencer2004]

Well most of us never really have a need to add these things to our bikes, it's just fun to do ^^

[Evil Ai!]

Well most of us never really have a need to add these things to our bikes, it's just fun to do ^^

Yeah well I tend to think of it like this.

Does the oil and by extension, the engine, need additional cooling? Yes or No?

How have I come to this conclusion?

Did I measure the typically hottest oil temperature that I occassionally encounter?

Did that temperature fall within the oils capacity to deal with it?

Did the high measured temperature fall within the lubricating capacity of the oil - for the average scheduled oil changes?

Did I consult the technical dept people of the oil manufacturing company - as to the oils mechanical limitations at the measured temperature and it's life expectancy?

Did I consult the technical / engineering people of the motor cycle manufacturing company?

Have I really thought through my decision?

Prior to purchasing a (thermostatically controlled) oil cooler?

Because if I do not have a FACT based reason for installing an oil cooler, for every $ I spend on an oil cooler, I have to work X hours, of which Y dollars is an expendable surplus and one needs to factor in Z hours of my time to fit and install the oil cooler.....

So I have to go an earn say $500, to have $100 to spare, to spend on an oil cooler, which will take say 4 or 5 hours to fit... (includes purchase time, travelling, tools, spares etc.) and I am capable of earning say $45 an hour in my off work time... to fit an oil cooler that I don't need.

So while you might classify this as a "fun thing to do", that if the oil cooler is not needed, on technical grounds, then whoever has done it - is tecnically inept, fiscally incompetent and is doing something that is a complete waste of time and one has technically pissed away $500 of earning time, to have the $100 surplus, to pay for the oil cooler, that costs me in my private earning time, some $200 - for something that I did not need to do.

Over cooling oil is BAD, it uses up more fuel, it doesn't boil out the moisture as efficiently etc., and it uses up the additives in the oil FAR faster, than if the oil was run within it's optimum temperature range - and it will do far more to shorten the life of the engine that on the basis of qualified technical advice, may be running within it's recommend temperature range.

Alll of this is like the hysteria of keeping your hard drives cool...

I have read the reports on the failure rates of hard drives and they have their longest lives at a far higher temperature than what one would think... contrary to the hysteria of the people selling you the hard drive and case cooling systems.

Most of the hard drives that fail are from OVER COOLING.

Like if you have 10,000 hard drives running at 20*C, 30*C, 40*C, 50*C, 60*C and 70*C.....

Based upon the data from the Google server farms etc., and the hard drive manufacturers, the highest failure rate is from running drives at an excessively cool temperature, and not at an excessively high temperature. The lowest mean time between failures - of the bell curve distribution, peaks over drives running significantly below the optimum drive temperature.

But the hysteria about the mostly mythical hard drive melt downs, is being fed to people from the manufacturers of cooling systems for hard drives. Without finding the report and sort of making this up just to illustrate the point, if a hard drives optimum operating temperature is 55*C - the failure rate is 3 times higher when they are run at 35*C, compared to 70*C.

But who is selling you this fanatical hard drive cooling hysteria? The manufacturers of hard drive cooling systems.

It's the same spiel from the manufacturers of the oil coolers.

ONLY buy and fit an oil cooler IF you have a genuine reason for needing to fit one.

Reasons are based upon facts - not opinions.

Contact the lubricating oil manufacturers, and ask them what is the recommended working temperature range of the oil that you are using.

If they say that it's good for 5000Km at from 125*C - 135*C, 1500Km at 135*C - 145*C, 500Km or two hours at 145*C - 155*C....

And your average oil temperature is around 130*C and it occassionally spikes to 140*C for an hour here and there; and your oil changes are supposed to be every 4000Km, then you can take it that your oil and it's additives, are working safely and the life of your engine is not going to increase by adding an oil cooler.

But get the facts about the product, from the people who make the product.

And then make a FACT based decision.

There is so much bullshit in marketing, opinions, clueless idiots with their 2c worth, and all that.

There are also some genuinely good "snake oil" salesmen - some of what is being sold is actually very good - and some of the bullshit they come out with is also very good.

But when it comes down to it, the infernal combustion engine has been running in assorted forms for like 200 years... people have been lubricating them with everything and anything - based upon, availability, cost, convenience and research.

I have a book called "Examination of Lubricating Oils" published in 1914 - it has all the best of the technology and testing proceedures of that time, by the brightest tribologists.

Sperm oil, cotton seed oil, olive oil, palm oil, lard, neatsfoot oil, graphite, greases, high speed motor oils, (steam) cylinder oils, Japan Wax, pine oils, the Navy dynamo oils...

Huge amounts of tests like viscosity, acidity, fatty acids, cold temperature tests, flash or autoignition temperature, carbon, sulphur, the iodine test etc., etc., etc......

And all the instruments and other equipment.

It kind of covers many transitional periods from greasing ox cart axles, to steam engines, to steam engines running super heated steam, and to internal combustion engines, dynamo bearings etc...

As nerdy as it sounds, get the books written by people in laboratories.

People needed to have parts running within other parts, they needed a way to make the parts run, without rubbing themselves apart.

They tried and used a huge variety of lubricants, in a huge variety of operations, temperatures, and pressures..

Some things worked really well, some things were passable, but not brilliant and some things ran like crap.

Then the technical people analysed the properties of the lubricants, the volatiles, the acids, the residues from elevated temperatures, the friction or energy used in the driving of the parts, the worn off materials in the lubricants,

I have to wind this up eventually - OK so the infernal combustion engine in all it's guises with all the lubricants, has been in use for a long time.

There is not a lot of magical mystery bullshit about lubricating them.

Some of the oils are over priced because of the magical properties they are supposed to have, and some of them are just plain old base stock oils with the regular additives.

The magical oils with the magical properties, might cost $25 a litre and the plain old base stock oils with the additives might cost $5 a litre if you buy it in 20 litre containers.

If I recall correctly - you have hotted up the motor a bit, and this produces interesting results.

You need less fuel to produce the same speed, and or less power strokes to produce the same speed.

Lower back pressure, better cylinder scavenging, bettter filling etc., and probably some higher gearing, makes for a more powerful but cooler running engine.

So unless your thrashing the bike, the motor should be running cooler.

So all the properties are known, of engines and lubricants - it's up to you to plug in the correct data - and extract the result.


Is your averaged maximum temperature within the oils working range?

What is the oil pressure like?

If it is running a bit hot, and consistently so, maybe a simple jump up in viscosity will be enough to remain within the oils reasonable working range.

[Krasi]

Not sure about the engine, but my head definitely needs an extra cooler after reading all that