oil cooler leaking on xj750. Problem Solved. (I hope)

i bought the bike with an aftermarket oil cooler on it and i noticed that it drips some oil every now and then. its most annoying when i ride hard and it drips onto something hot and starts smoking (scaring me sometimes)

my question is. what can i do to stop the dripping. and in the case that i cant stop it. should i just get rid of the oil cooler all together. what are the steps for removing it properly. and do you think there will be a major differnce in having the oil cooler or not.

thanks.

 

Re: oil cooler leaking on xj750. help.

If you ride in a hot climate like I do you really need an oil cooler. When the oil temp. keeps going up the oil pressure keeps going down until it reaches zero, which is not good for the bearings. In your area you may be able to get by without it but I would just fix the leaks.

 

Re: oil cooler leaking on xj750. help.

BTW, if all the riding you do is around town you may not need the cooler. I have oil temp and pressure and head temp. gauges and when I start up the engine the head gets up to 300 degrees F. in just a few minutes but if all I do is tool around town the oil never gets hot enough to register on the gauge with the pressure around 80 PSI but if I drive 80 MPH on the freeway for only 15 min. the oil temp. goes way over 200 F and the pressure drops to near zero without the cooler. With the cooler installed the temp. stays around 150 and the pressure never goes below 40 PSI or so.

 

Re: oil cooler leaking on xj750. help.

That seems way backwards to me.. Considering these are air-cooled engines, wouldn't one think the faster one is going (and thus the faster the air is moving past the engine) the cooler the engine will stay? Low speed stop and go traffic around town would cause the higher temps.

If thats the results you saw, thats what you saw.. But it makes absolutely no sense to me.. :?

 

Re: oil cooler leaking on xj750. help.

What kind of cooler do you have and how is it attached to the motor? This will point out to us what parts/bits might need replacement. Pictures or diagrams please.

 

Re: oil cooler leaking on xj750. help.

TaZMaNiaK, it makes perfect sense. when the engine is producing the most power it also generates the most heat! When it's just idling along and not producing much power it doesn't make much heat. Haven't you ever had an engine overheat while pulling a long hill? At any given time you can see several of them along the road boiling over going up the mountains north of Los Angeles. I can actually see the temperature rise when going up a slight hill on the freeway. BTW, the engine head temperature doesn't change much, just the oil temp and there's no air cooling for the oil, which is why it needs the cooler.

 

Re: oil cooler leaking on xj750. help.

I think he needs to send it out here for... "extensive testing". Yeah. That's the ticket! :mrgreen:

 

Re: oil cooler leaking on xj750. help.

Nope, never had one overheat on the highway. Only in traffic.. Both belt driven and electric fans. 6K is 6K, whether its in 1st gear or 5th . But the air rushing by the cooling fins is moving a lot faster when the engine is doing 6K in 5th than 1st, therefore it should be cooler at highway speed.

 

Re: oil cooler leaking on xj750. help.

>But the air rushing by the cooling fins is moving a lot faster when the engine >is doing 6K in 5th than 1st, therefore it should be cooler at highway speed.

Oil doesn't go through the fins on the engine! That's why you need the cooler, air rushing over the cooler fins cools the oil!
Have you ever seen an engine or know anything at all about how they work?
I suggest getting a basic book on engines and reading it.

 

Re: oil cooler leaking on xj750. help.

The cooling of the engine is dependent on the ambient temperature of the atmosphere.

The Cooling fins are there only to expose a larger surface to the atmosphere.
Those "Up-North" can race their engines and let them Idle all day long when ambient temps are below 65-Degrees F.

Our Southern Bros. & Sisters don't have the luxury of being able to operate a bike at "Room Temperature" They need to have some "Movement" so that the Cooling Fins have an atmosphere in which to allow the heat to escape.

The Oil Cooler exposes engine oil to an ambient temperature outside of the engine cases where it releases its heat to the atmosphere.

Weather (sic) or not you live in the Sun Belt or the Snow Belt ... an Oil Cooler is a welcome addition to extending engine longevity.
If the cooler is leaking because a Gasket or an O-ring is leaking ... that's an easy fix. Do it.

If a line is leaking that's another story. I wouldn't trust a patched Oil Line.
I'd replace the line with a new one.

 

Re: oil cooler leaking on xj750. help.

im gonna take a picture of it tommorow morning and post it. it leaks right the hoses come out of the oil filter cap. so its probably lose gaskets or something. ill get those pics up right away.

 

Re: oil cooler leaking on xj750. help.

No need to get snippy sir. I didn't insult your intelligence, I'd appreciate it if you didn't insult mine. I have been working on engines most of my life. Lawnmowers, go karts, dirt bikes, quads, cars, and bikes. If I owned it, guess who fixed it? My father has been in the automotive business for the past 40 years so I think I've picked up a thing or two.

I KNOW the oil doesnt flow THROUGH the fins. But they are there to help dissipate the heat to the air. Notice that there are fins ALL OVER the engine, including the sump pan and oil filter housing. So they DO play a role in oil cooling. And since higher speed = more air flow, I would still like to know how you can run hotter on the freeway than in town. Like I said, I've never seen anyone pulled over on the freeway with steam pouring out. I have seen, however, MANY cars overheat in traffic.

 

Re: oil cooler leaking on xj750. help.

If it's the OEM Yamaha cooler you will probably just need to replace the o-rings inside the connections.

 

Re: oil cooler leaking on xj750. help.

IkeO, Mac and Rick are right on the money. Replace the o-rings. But is sounds to me you have a thread/seal problem with the line. You may find that pulling the line and putting a few wraps of teflon tape around the threads will help seal it up.
Back to the thread-jack.
Gonna side with Taz on this one Steve. Owned 14 VW's (one aircooled) and learned a great deal about air/oil cooling with the time I spent with the aircooled. You are far better off at freeway speeds with an air/oil cooled engine than in-town driving. More airflow=cooler engine, at least in this regard. There were several tricks you could do to improve cooling for your aircooled including a bigger fan, extending the oil sump (adding the extra quart helped drop temperatures as well) added extra cooling fins, as well as auxillary oil coolers. I used to sit in traffic in S.D. and watch my cylinder head and oil temps climb, only to drop dramatically whenever I got the beast moving or brought the RPMs up.

 

Re: oil cooler leaking on xj750. help.

All the "Fins" on everything are intended to increase the surface area that will allow heat to dissipate from the areas which get the hottest.

The increase in air-FLOW doesn't cool the engine. It moves away air from the cooling fins which has been "used" by the engine to allow the heat to escape.

The greater the FLOW, the more surrounding atmosphere is "changed" allowing the heat of the engine to escape.

This factor is why you should keep the engine block clean. A dirty engine will act like wrapping the engine in a blanket and keep the heat from dissipating into the atmosphere surrounding the block.

 

Re: oil cooler leaking on xj750.(problem solved, i hope)

ok sorry it took a while to get this pic up. i think the problem has been solved. thanks guys. i just cleaned it up as best i could and tightened the gaskets alot more than they currently were. so far i havnt seen a drip of oil and its not smoking anymore. so i think problem solved (crosses fingers) its really really hard getting a good pic of this oil cooler at the filter housing connections. but this is the best one i could take. its very well hidden behind the exhaust pipes. the oil was dripping from the spots where i drew the red circles.

 

That's an old Derale cooler, not a stock Seca cooler. You could unscrew the 90's and put some Teflon plumbing tape on them to seal them up properly once the riding season is through.

 

I don't know what PSI the Hose Clamps and that Hose you are using is rated for ... maybe during the off-season you should consider running some High-Pressure and High-Temp hose and have the fittings worked for hot, high-pressure oil; too.

 

Those look like aluminum AN fittings. If they have been stripped, you will see oil leakage (they are pipe threaded, don't overtighten them). You can use teflon tape for a quick fix but I would upgrade as Rick suggested at first opportunity.

 

Go to plumbing supply house and get some high quality Teflon tape it is pink in color. Wrap the male threads leaving the first two threads unwrapped to aid in starting of the fitting. The tape is a lot thicker then the cheap white stuff. I have never had a leak in all my plumbing fittings. Don’t let your friends make fun of you using pink tape!!