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Solved Over heating issue FML

Discussion in 'Technical and Troubleshooting Torque' started by cool jesus, Sep 10, 2016.

  1. Well, talk about 11th hour defcon 4 disaster, just before a massive ride.
    Ok its a 2012 Aprilia rs4 125. Couple of weeks ago the nozzle broke of the thermostat housing, leaving me stranded.
    New housing arrived, drain any remnants of old coolant (was something called 'blue ice' for bikes). In draining the coolant I also removed the water pump housing. Put everything back, only added a real small amount of sealant around waterpump (which has a small rubber oring gasket) and the thermo housing. Also added a little on the return house (both ends) which I've never done before. Topped up coolant, this time I used red motor vehicle coolant, warmed up the bike, felt return house to see if thermostat was still working (Yes), also check for heat at waterpump end (Yes to heat). No problems or leakes after to short half hour hard runs, then tonight coming home, sitting in traffic the heat gauge sky rocketed and shot up the over heat warning ARGHHHH!
    Let the bike cool down and managed to nurse it home the next couple of K's. On the final leg again the bike started to over heat whenever I stopped for more then a few minutes. Radiator fan is working and all parts, radiator and hoses are hot.

    My thoughts!
    1. Waterpump has now failed
    2. Wrong coolant
    3. Thermostat blocked
    Any ideas would met with blessings, disease healings, promisory note into the ivory gates, please, please, please anyone out there.....

  2. 1 or 3, but if I had to pick then 3. Good luck mate
  3. I could just run without then yes? Coolant wouldnt be an issue...
  4. I would say yes.
  5. Actually, is it possible to have cooked the thermostat from my last overheat incident? Could it have been ruined?
  6. didn't think to check to see if it was working properly before throwing it back in.
  7. Anything is possible.
  8. Well gonna have something to eat, then look at pulling the thermo out later tonight. Cross fingers.... thanks Andrew WestAndrew West.
    • Like Like x 1
  9. All airbubbles out of the system?
    • Agree Agree x 2
  10. It does seem to be sucking coolant from the reservoir (it was down a little), I did add that as a thought as I'm close the the capacity for coolant. But maybe?
  11. Mixing coolants could have caused an issue. It's always recommended to flush the whole system as much as possible before changing types (even brands because of additives). Give it a few decent rides with straight water to get rid of as much of the old stuff as possible. In this case your typical red coolant is ethylene glycol based but the engine ice stuff is propylene glycol based. The two are miscible but the additives often don't play nice. Do this regardless of what you find the issue to be, could save a hell of a lot of headache later. Remember to use distilled water if mixing from concentrate. 50/50 is the typical mix for most bikes.

    It could also be air bubbles. Check out your service manual for proper bleeding procedure for that bike. When you refill you usually need to top it up a bit after they've been bled out.

    Thermostat can be checked in a cup of boiling water and a thermometer.

    Water pumps rarely fail all of a sudden. You might be able to feel coolant flowing in the hoses, or pop open the radiator cap (if on the radiator itself) to check for flow after the thermostat has opened.
    • Like Like x 2
  12. Yeah, I was careful, hmmm maybe not careful enough now that I think of it. I know that mixing the two can creat a gel like substance and screw things up....
    Like to hear its not the water pump, I'll double check more closely as you suggest.
    When I pop the thermo out later tonight I'll check it too. Should have done it in the first instance. Damn this shit sucks....

    Don't think its air bubbles, but maybe.... I have been known to be wrong before (back in 1937) and don't want to rule it out just yet. About to head out and see if its sucked siome coolant after cooling down.
  13. #13 Steve Vtec, Sep 10, 2016
    Last edited: Sep 10, 2016
    Mate I'll pm you my address, uber or taxi over in the morning and you can take my cb400 for the Sunday ride if you don't get it sorted. I'll be up early, call or text
    • Winner Winner x 6
  14. Well, looks like I may have been wrong in 2016, after cool down the engine sucked up another 100ml or so of coolant. Air bubbles, GeorgeOGeorgeO HarbHarb, thanks guys I'm starting to think this was my problem. Thermostat is definitely working by feel of hose temp. I didn't see coolant moving at the cap, I'm fairly sure the pump is OK the hose changed temp with the thermostat opening.

    No special procedures to refill, in fact there was nothing on it. I filled it real slow and the radiator cap has a pressure valve to expel and ingest coolant as required by temp. Its also well above the engine height, so to me this indicates its a self bleeding system. There's definitely no leaks, so without any further insight I'm just gonna top up and ride :nailbiting:
  15. You're an angel dude... keep those rainbow farts blowing out of your firestorm Vtec monster
  16. No vtec on the firestorm. That would be a little too hectic I think ;-) the cb400 is a little screamer tho, you'll have to have a go on it one day
  17. 1. Is the waterpump mechanical or electronic on the Aprilia?
    If mechanical, you can test easy by filling the radiator, but leaving the cap off when cold.
    Start the bike, and rev it a few times. If pump is working, the coolant level will dip slightly as you rev.

    Possible you have blocked a channel by using too much sealant when putting it back together?

    2. Always stick to the Manufacturer specified coolant. Can't imagine that would be the issue though.

    3. Thermostat is most likely candidate, they do just go randomly.
    Test it by removing from the bike, ensure it is closed when cold.
    place in a pot of cold water on your stove top, and heat the water to boiling.
    Thermostat should be fully open when the water is boiling.

    Don't be tempted to run the bike with no thermostat installed. You can damage aluminium engines very easily that way!

  18. OK, glad I left it in then. Thanks.

    It's a mechanical pump, did try your check with no real evidence of it running. I'll did it again though, but without a pump I doubt I would have had the Netrider run today.

    As it is, its still overheating. Sorry 69SIM69SIM SibiSibi KimiKimi , had to break our little formation as that little bit of stop start traffic was send the tempurture up and I had to get to the M2 sooner, rather than later to get some air blowing through the radiator.

    The only real variable I have at the moment is the coolant, going to go back to what I was using and double checking at the same time that its OEM compliant.

    I'm still leaning towards the thermostat, as its had a blast of heat when I broke down some weeks ago and I reckon this would have effected it.

    I only used minimal sealant (against my better judgment) and left it to cure for over 24hrs, so not impossible, but I don't think this would have caused my issue.

    Just to add to my diagnosis, I'll be double checking the thermo fan function. Although its gioing full bore when real hot, I'm wondering it its a 2 stage fan. It normal is running when I parked it at home and today it wasn't and the temp was up above normal. Hmmm such a headache. :banghead:
    • Like Like x 2
  19. No worries!
    Hope you get it all sorted soon!
    • Agree Agree x 2
  20. No probs at all. I noticed the XSR was running the fan pretty much all the time once we hit traffic...