Problems with the water works...

[divelandy]

I'm with a friend whose 2007 Dakar's radiator sprung a leak which was temporarily fixed by adding curry powder - not something I'd heard of.. .

After replacing the radiator and flushing the system with a low pressure hose, we reassembled, squeezed the hoses and thought we were done.

After going out for a ride, some coolant pissed out of the top of the reservoir when we stopped and the temp light came on.

We went back to the house and the same experience when we stopped. Repeated filling the radiator, and this time used the vent nipple above the temp sensor on the r/h of the engine. Bled, ran for a minute, bled, ran for a minute. Gas kept coming from the bleed nipple.

When we came for a test run, the bike would not start. The spark plugs were damp - i thought from petrol from the lots of failed start attempts. Replaced the plugs and the bike started. The exhaust gases were not as clean as usual - i thought because of the unburned fuel.

Went out for another ride and on the way back, the temp light came on, so stopped few times.

This morning, we checked the water pump which looks on good condition. Not much coolant came out when we drained the system.

Any ideas on the cause?

Thanks.

Steve in South Africa

 

[Timpo]

Is the oil turning milky coloured?
Is the rad becoming pressurized staright away after starting the engine.
Could be cylinder head gasket is weaping.....

 

[divelandy]

There are no signs of water in the oil. The hoses become pressurised when the bike is started.

 

[divelandy]

My worry is head gasket, but wanted to source opinions of those who know these bikes better than I...

 

[(RIP) Tunneruk]

It's possible that you have a gunked up thermostat which wouldn't have opened up when you flushed the engine through with cold water

 

[divelandy]

Is the thermostat just a switch for the fan? The fan comes on when the bike warms up. Will take the thermostat out later to check.

 

[Packer]

The thermostat stops water going through the radiator until the water gets to the design temperature and the 'stat then opens. If it is gunged up with curry powder it may not open properly and the bike will overheat.

 

[flatdog]

Take the radiator cap off and start the bike if the filler area bubbles with water and air the Head gasket will be blown between compression and water. Curry will cook and solidify in the smaller pipes and muck up the whole system and even block the radiator up so that's not a good idea, if it were mine I'd start stripping after doing the compression check above.

 

[Dansin]

Sounds like the thermostat is now not working. Pull it out and drop it into a pan of water and bring to the boil to see if it opens. If the temp light comes on when riding you need to stop the bike asap as it's really easy to warp the head. If the thermostat is goosed don't run it without one as that will also cook the engine.

 

[divelandy]

Starting the bike without the radiator cap resulted in a lot of the coolant being ejected.

The radiator is new

Will take a look at the thermostat today.

 

[divelandy]

Thermostat works perfectly. Now understand that there is a thermostat and two position electrical switch for fan and overheat lamp.

Went out today after assembly and it pissed coolant again. Looks like we need to look at the gasket