MP3 500 overheating at motorway speeds
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Lurker
2014 MP3500
Joined: 16 May 2019
Posts: 4
Location: UK
Thu May 16, 2019 12:45 pm quote
Hi all. I have a weird overheating issue with my MP3 500. For normal riding around town and under 65mph temp is fine, gauge is in the middle (our even below) and will stay there all day. However, if I ride at over 65mph for more than a few mins the temp begins to climb and heads to red zone. If I slow down to about 5k rpm it settles back down to middle of the gauge.

I've drained the coolant and bled the system - based on volume of coolant I put in I think there's very little if any air in there. I've watched the level and its not leaking or losing coolant either. I checked the impeller on the water pump and this also seems to be fine - I had thought it may be worn and was cavitating at high speed. I read somewhere that someone suggested it could be the thermostat allow the coolant to flow to fast around the engine at high speed and not allow enough time to properly cool.

Any thoughts? Weird problem and is annoying to be stuck at <65mph
Veni, Vidi, Posti
Neutrino MP3 492.7 AK, 2013 Moto Guzzi Norge
Joined: 29 Mar 2008
Posts: 21207
Location: Kingston, Tennessee, Tn
Thu May 16, 2019 1:04 pm quote
is the fan kicking on?

I suspect an air pocket in the system
Lurker
2014 MP3500
Joined: 16 May 2019
Posts: 4
Location: UK
Thu May 16, 2019 1:08 pm quote
Yes, fan kicks in when it should. I agree it sounds like an air pocket but I'm getting liquid only out of the bleed plug. V. confusing.
Veni, Vidi, Posti
MP3 500, GTS 250 (both 2008 MY), 2010 Can Am Spyder RT-S, 2012 Honda NC700 DCT
Joined: 02 Mar 2013
Posts: 5129
Location: Madison, Wisconsin
Thu May 16, 2019 1:11 pm quote
Thermostat not fully opening?
Hooked
2008 fuoco.T3 guzzi california outfit
Joined: 19 Jul 2015
Posts: 180
Location: United Kingdom.
Thu May 16, 2019 1:15 pm quote
If the thermostat was stuck open then the coolant temp would be showing low not high. I would investigate the thermostat as MS says it may not be operating as it should.
Molto Verboso
Kymco AK550
Joined: 09 Feb 2008
Posts: 1069
Location: UK
Thu May 16, 2019 11:46 pm quote
Yes this is a symptom of the thermostat not opening. Feel the temperature of the radiator and/or the radiator feed and return pipes and you might find that the radiator is not hot, whereas it should be very hot if the gauge has gone up. Did you bleed the system at the cylinder head? If there is an airlock around the thermostat it will not open properly.
Lurker
2014 MP3500
Joined: 16 May 2019
Posts: 4
Location: UK
Fri May 17, 2019 2:51 pm quote
Thanks all, very helpful.
Hooked
MP3 500 LT " Matilda"
Joined: 21 Dec 2018
Posts: 128
Location: west Germany
Thu May 23, 2019 1:36 pm quote
awest wrote:
Thanks all, very helpful.
I would suggest that you have your Freezeplugs checked also. I had to have a Major Oberhaus Matilda's Motor because of a defective Freezeplug.
Veni, Vidi, Posti
2008 MP3 500, 2013 BV350
Joined: 13 Oct 2012
Posts: 6744
Location: Ashburn, Va. Home to the Internet
Mon May 27, 2019 3:52 am quote
Hillbilly Fred wrote:
awest wrote:
Thanks all, very helpful.
I would suggest that you have your Freezeplugs checked also. I had to have a Major Oberhaus Matilda's Motor because of a defective Freezeplug.
What was defect?
Did it leak?
How long between coolant changes?
Ossessionato
2016 MP3/500 Sport ABS, 2009 MP3/250, 2012 GTS Super 300ie
Joined: 08 Jul 2011
Posts: 4185
Location: Marietta, GA
Thu May 30, 2019 5:56 am quote
Madison Sully wrote:
Thermostat not fully opening?
That's what I was thinking...

Keith,
Marietta, GA
Hooked
Joined: 27 Oct 2016
Posts: 214
Location: England
Thu May 30, 2019 6:53 am quote
klaborde wrote:
Madison Sully wrote:
Thermostat not fully opening?
That's what I was thinking...

Keith,
Marietta, GA
and me too......

Check the rad when the block is hot, if not hot bleed system or change thermostat.
Lurker
2014 MP3500
Joined: 16 May 2019
Posts: 4
Location: UK
Mon Jun 10, 2019 12:55 am quote
Found the problem
Turns out it was a split in the impeller so at higher speeds it was slipping on the shaft. Of course this super cheap fix was not discovered before I'd spent the money on having the thermostat checked (and all the time consuming gubbins removed to get at it)
Molto Verboso
2018 GTS300 Super Sport - Donatello Vespace
Joined: 22 Dec 2012
Posts: 1017
Location: Toronto, Ontario Canada
Mon Jun 10, 2019 5:29 am quote
Very nice tour. I was not aware of Bitza's passing - so sad! I had been "away" from MV for almost a year due to some unexpected "things" in our lives. Thank you for dedicating this to him.
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