Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Overheating?

[jim flynn]

Can anyone help with this question?

I have put a 998 style race fairing on my 748 so less air gets to the engine now. I got home from a ride on saturday and noticed that the red oil light on the tacho was blinking on and off intermittently and that there seemed to be some coolant sprayed in the cockpit. The temp gauge was still some way from maximum.
I got the bike out the following day and checked the oil and coolant levels. The coolant looked a bit low but still over the minimum mark. The oil looks like it was overfilled at the last service as the window was full.
Could too much oil be causing the problem? Could it be lack of ventilation due to the race fairing? The bike ran well all afternoon and I only noticed the light blinking as I pulled into the drive. What should I do to prevent the problem? I plan to top off the coolant and drain a bit of oil at the weekend. Any suggestions?

[antonye]

It sounds like both your oil pressure sensor has gone AND your coolant tank has split. This would explain both the blinking oil light and the coolant spray.

These faults are both quite common and both quite easily fixed!

[antonye]

eg...
http://ducatisportingclub.com/xmb/vi....php?tid=10746

[jim flynn]

I rechecked my oil level today and the sight glass was filled with oil. I drained probably a good half litre and now have the level between min and max. I also put a drop of distilled water in the coolant expansion tank. I ran the bike for about 10 minutes getting it up to 180 degrees and saw no evidence of any coolant leak. I had the fuel tank off for a better look at it and couldn't see any split or leak. Also the Oil light stayed off, no blinking at all while running. Did come on with ignition switch and went out once started up. The coolant spray is still a mystery, though I did take off the expansion tank top. I found that the rubber washer wasn't seated right so I gave the top a good flush under the hot tap and reseated the washer.
Will take it out for a run tomorrow to see if there is any repeat of the problem. I am guessing that the oil light came on because of excess oil in the engine. Fingers crossed things are ok now!
Not happy that Moto Rapido put excess oil in when they serviced it though. Will be having words on monday!

[marksduc748]

hey! you cant throw a quid on the floor in front of her on your pic can you. cos thats one hungry ass cos its eaten her pants.

[jim flynn]

OK just back from a quick test run of about 35 miles. No problems from the oil light at all so I reckon that problem is cured. I am still getting some spray from the expansion tank though but I just can't see where the problem is.

Looking at the areas getting wet my instinct tells me that there is something wrong with the pressure cap. I can't see any splits in the tank itself and we are not looking at catastrophic amount of coolant escaping, probably only a tablespoon full.

Where are the common failure points on these things? Is the screwneck a weakpoint? Do Pressure Caps fail a lot? Any good ideas?

Cheers,

Jim (Doing Track Attack 3! )

[antonye]

There's a seam in the plastic which is the weak point in the coolant tank.

The only problem is that when you're riding the bike the air comes in and forces the coolant up and out at the top, so it looks like the leak is coming from the neck of the tank.

You may be able to do a plastic weld on the tank, or use a temperature controlled soldering iron with a wide flat tip and run that down the seam, but it's probably best just to replace it ... I think they're about 20 quid from a dealer?

[JPM]

I've seen one of these go bang big time, bike idling away, then kaboom!!!

Split along the seam as described, better replace it for the price, not worth trying to bodge it, and then having to strip the bike a second time to replace.

[jim flynn]

Had a chat with the guys at Moto Rapido about this. Could be a hose, the pressure cap or the tank has split so am going to try and eliminate likely causes to see what needs replacing. First to check is the hoses, check condition and fit, then the pressure cap, have borrowed one that will go on tomorrow, then go for a blast and see what happens. In the meantime I will dig out the part numbers for what I might need.

[jim flynn]

Well had a look and I think I have cured the problem. When I was checking the hoses I noticed that fluid had collected in the recess around the filler neck. This couldn't have been from the previous run on the bike as it would have evaporated away. This made me think of checking the O ring seal in the filler neck. On looking I found that the area around the O ring was clagged up with deposits from the fluid like limescale. I removed the O ring, cleaned the filler neck up, cleaned and regreased the O ring and refitted it. Took the bike for a quick 20 miles getting it nicely warmed up. Got home and no sign of a leak and still none. Might be an idea to check the O ring before buying all new parts!