BMW S1000RR Forum banner

Water temp puzzle!!

4K views 15 replies 3 participants last post by  bennymx 
#1 ·
Hi all, I have done a trawl of this forum but couldn't find a solution to this particular problem.

Whilst racing at the end of last year, I took a heavy fall and it's been a bit of slow financially controlled rebuild. Pretty much done most of it myself apart from some final issues I have had which have been resolved by the garage I use.
The bike is now complete apart from one final fault. The water temperature reading never raises above 40/50c despite the bike being run for a time where it should be 90/100c.
The sensor has been replaced which has made no difference. When I first got the bike the fans were disconnected and they have only been reconnected during the rebuild (not tried disconnecting them again).
The bike has had a new instrument cluster as part of the rebuild which appears to be working fine.
It was on the dyno yesterday afternoon and was reading a constant 187, which maybe a bit low because we assume the bike is compensating for the apparent low temperature.
The bike is currently still at the garage and I'm after any feedback or advice I can take to them early next week as the frustration of not being able to get on track has reached boiling point! I'm not sure if the fan issue is a false clue as obviously they have still not been engaged.

Although I'm desperate to get the bike out again and I think it would probably be ok to do so, I would prefer to get this issue sorted first.

Cheers

John
 
See less See more
#4 · (Edited)
The thermostat is designed to be closed to allow the engine to warm up. Once about 70-80c is reached it will open. You can check this by removing the thermostat and placing in boiling water and watch if it opens. You can do a quick on bike check before this. Start the bike and check the temps of both the top and bottom rad hoses. One will be hot once the bike starts running after a bit and the other side should be cold. Once the thermostat opens up at 70-80c it will become hot as coolant flows through it. A closed thermostat will cause the bike to over heat. You have replaced the temp sensor so it's not that (we hope). I would check the wiring on all of that between the temp sensor connector and the ECU. But first do the rad hose check to see what's going on there. If it's not warming up the thermostat could be stuck open from the get go. You can time the engine from start up and see how long it takes to warm. These bikes heat up very quickly and it should reach 100c very easily and then the fans should be on at 103 and shut off once it cools to 97 approx.
 
#5 ·
That makes perfect sense, I will try hopefully tomorrow if I can get to the garage. Would that fault not show up if it were connected to the diagnostics computer?
Failing this I will check the wiring, however not 100% what I will be looking for particularly!!

Cheers John
 
#11 ·
Just managed some time at the garage. When the bike ignition is turned on, the temperature is reading MINUS 78, when it is run up for a little while it never goes above + 50c, doesn't seem to be a problem with thermostat. As I mentioned earlier this is a replacement sensor and the previous one was having the same readings.

Any thoughts?

John
 
#9 ·
the first time i hit 150mph a rock put a hole in my radiator. i didn't realize for 10 minutes or more. our group happened to stop to rest and that is when i noticed my boot covered in coolant and coolant spraying from my radiator onto my front tire, wheel, rotor, engine, everything.

the gauge never went above 210. i let the engine sit for an hour to cool down, then tip-toed my way to a place with cell reception to fetch a ride. luckily the thermostat stayed closed the whole way to reception point so it didn't spit any more coolant.

not sure what the point of this post is anymore lol other than maybe to stress the fact that we should all have radiator and oil cooler guards oh yea and if you play stupid games like 150 on the street you will win stupid prizes like a hole in your radiator 120 miles from home
 
#13 ·
No I'm quite happy with what is what.
Why do you ask?

The sensor has definitely been replaced. I say the thermostat may be ok as on testing the pipes they both were not hot after starting.

It is the - negative temp reading on the dash clocks which is now causing me the confusion.

Cheers
 
#14 ·
When you check the rad hoses. One side will be hot to start with. One will stay cold until the thermostat opens. So I want to know once the bike is hot. Are both hoses hot? Telling me they are not hot after starting is not what I need to know.

Also. If you let the bike run for say 10 minutes at idle. Do the fans come on at all? And if they do come on, do they switch off again?
 
#15 ·
Apologies Benny, I knew what I meant :nerd:Only one hose gets hot after running for a while, then a few minutes later they both are then hot.

The garage was able to to access the ecu through the diagnostic software which had not been available last week. Interesting results.

Upon starting the bike the ecu is telling the diagnostics that it is 15c however the dash shows -40. After the bike is run up to temp, around 90c (on the diagnostics) it displays 60c on the dash. At 101 the fans cut in and successfully bring the temp down, at this point the dash and diagnostics read 99c!!??

The garage is happy the bike is running fine and the cooling system is working ok despite showing incorrect details initially on the dash. The question is if I'm happy to accept it as it is, or spend more time and money (lost racing) further sorting the fault.
I'm leaning towards getting the bike on track and seeing how it runs.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top