[h13man]

Hard wire the fan by by passing the thermo fan switch and run the fan manually. This might help determine is the light sensor is bad or something else is admiss.

 

[RONW]

Anyway, from what I read here, I should check for the water pump and the radiator cap. I have no ideas how to check those parts. Are there some easy checks that I can perform myself or should I go straight back to the mechanic ?

*Start a new thread on the topic.

You may have been right all along though ....

.... I begin to think that the issue may not be "not enough cooling" but "too much heating".

 

[7xclm]

See if you an find one of these. It will show the temperature of the radiator. If it is over 82* Celsius your radiator is too hot. I would check the thermostat then. If it is not over 82*c then you have a bad sensor controlling the light or the fan.

http://www.amazon.com/s/?ie=UTF8&ke...vptwo=&hvqmt=b&hvdev=c&ref=pd_sl_7icwdd2e0h_b

 

[Eagle7840]

Originally Posted by Eagle7840
Replace the radiator pressure cap with a new one. Keep it simple!

Huh? :???:

If the radiator pressure cap is bad then the radiator is not pressurizing and will cause the engine and coolant to overheat. This has been discussed many times on the forum.

 

[jpr1968]

Actually it doesn't necessarily cause overheating but he would have had coolant coming out and he didn't say he did.

 

[jpr1968]

*Start a new thread on the topic.

You may have been right all along though ....

Why should he start a new thread on the same subject?

 

[Eagle7840]

Wow guys, thanks for so much replies ! The thing is I have close to 0 skill in mechanics, so I likely misused some words and I may not understand some things.

To sum up my situation in simpler, (and I hope) more accurate words :

• 
  During the following weeks, the warning temp light switched on again but would switch off as soon as I was able to gain speed.

• 
  Then, the warning temp light started to switched on more often, almost each trip to or from work. I ride twice 12.5 km in Paris to go to work, sometime with heavy traffic.

• 
  I went to a different mechanic and he told me that the thermostat (the thing you boil in water to test it) was stuck close, preventing the coolant to flow.

• 
  This guy changed the thermostat and one heat sensor that had melted. But I don't know if it was the fan heat sensor or the warning light heat sensor. The bill just says "contacteur thermique" (Google translates this to "thermal contactor").

• 
  According to the bill, the coolant was completely replaced. The mechanic said "the coolant is flowing as it is supposed to do" (but in french of course ).

• 
  From this point, it went from bad to worse. The warning light switched on for each trip, sooner and sooner, and harder and harder to switch off by gaining speed. The last time I used my bike to get back from work, it switched on after no more than 15 minutes in traffic. I didn't think to check anything, I was too upset and worried to burn my engine.

Anyway, from what I read here, I should check for the water pump and the radiator cap. I have no ideas how to check those parts. Are there some easy checks that I can perform myself or should I go straight back to the mechanic ?

Thanks for a good background description of what is happening and what has been replaced by your 2 mechanics. Your key descriptions are that it overheats in slow traffic and the temp light turns off at higher speeds. At lower speeds there is less air flowing around and thru the engine cooling fins causing your bike's engine to overheat. Since you've had the thermostat replaced, several sensors replaced and the fan works like it's suppose to, it's time to look at the radiator cap which is suppose to keep the coolant below the boiling point by keeping the radiator pressurized. A failing radiator cap will cause an engine to overheat just as you described and will worsen till it no longer can hold pressure. It's easy to replace if you follow the steps involved to get access to it and much less expensive than replacing the water pump first and then finding out that the pump was fine and the cap was bad.

 

[RONW]

Why should he start a new thread on the same subject?

In the real world, once you finished testing the thermostats, you would call it a wrap and move on to testing the radiator cap and the waterpump. However, on a forum, there'll be for example 6 consecutive post on radiator caps and waterpumps, only to be interrupted with a post on thermostats again.

So, if the OP were to make a clean break and start a new thread on waterpumps & radiator caps, those inclined to continue discussing thermostats could post it on this thread. Whereas waterpumps & radiator caps would be discussed on it's own dedicated thread even though it's clear that we're talking about the same bike.

 

[h13man]

After some thought and a trip down memory lane so to speak I caught up on the pressure cap angle of this thread. Duh. Yes it could be the pessure cap if it isn't opening and letting the coolant bypass it to the resivior or on the ground but that much pressure build up I would think that should have caused some more prominent leaks or problems especially the time extent of the problem.

As for a new thread? Really guys? We got 3 mos. or so of winter layup. :lol:

 

[jpr1968]

I thought the *suggestion* was self explanatory. For the record, if the radiator cap question and the waterpump question were grafted onto this thread it'll get like too many tools in the toolbox. Sure the thread was originally on overheating issues to which faulty waterpumps and faulty radiator caps are possible causes.

However the last I checked the solutions began to focus on faulty thermostat(s) as being the culprits and to a degree that tossing in malfunctioning waterpumps & radiator caps into the mix would be disorganizing. *Disorganizing* as in un-compartmentalized.

In the real world, once you finished testing the thermostats, you would call it a wrap and move on to testing the radiator cap and the waterpump. However, on a forum, there'll be for example 6 consecutive post on radiator caps and waterpumps, only to be interrupted with a post on thermostats again.

So, if the OP were to make a clean break and start a new thread on waterpumps & radiator caps, those inclined to continue discussing thermostats could post it on this thread. Whereas waterpumps & radiator caps would be discussed on it's own dedicated thread even though it's clear that we're talking about the same bike.

total bs

 

[RONW]

total bs

If you ever bother to read a post twice before posting a comment. Maybe you'll get things right.

As for a new thread? Really guys? We got mos. or so of winter layup. :lol:

Okay, how's this sound? Radiator cap .... just buy a new radiator cap if you even suspect that it locks open. On the other hand, ain't no way it's gonna to stay closed under all that hydraulic pressure. Problem solved. Faulty radiator caps can't be fixed. And they're cheap enough.

About the only problem with waterpumps is if they develop leaks around the o-ring, seal, or gaskets, drain bolt, and drip coolant on the garage floor, n that'll be as obvious as a leaky radiator. If it's impeller related it's a buy new. A clog or a partial clog, that's rare.

But ignore the above. See, if every body were to agree with every thing spoken about radiator caps & water pumps hereonafter, then tacking those possible culprits onto thermostats culprits, wouldn't be disruptive. Won't go every which way.

But that won't happen. It'll be like the thermostat, valve or sensor, debate. The radiator cap doesn't do that, it instead does this. The waterpump doesn't work like that, so forth. That's behind why I *suggested* starting a new chapter. Ain't important.