Coolant Replacement 5th Gen

Yea. What he said. 'Cuz I wanna know too.

Good questions, BA. Hopefully someone will provide you (us!) with an answer.

 

Took my 5th gen out of hibernation today and decided to let the engine run a while as there was some acf50 overspray to burn of ton the exhaust headers,
anyway after about 15 mins I'm just ready to take her out for a short spin and I look and there's steam rising from her and coolant all over the ground!!
don't know what's gone wrong, before I start stripping her down has anyone any idea on what might have caused this?

 

Also is it worth taking that 10mm bolt out above the oil filter to drain the engine coolant a bit more? I'm a bit worried it's been in there so long it could just snap off when I try to remove it! I'd imagine the bolt on the water pump will let most of the old coolant out.

 

First question is where is it coming from? If it is from the reservoir, you may have either overfilled it (unlikely) or the radiator cap needs to be replaced as it is not holding pressure. Without that pressure the coolant in the engine can boil prematurely and then steam burps coolant out of the reservoir.

 

Thanks Terry, it definitely wasn't overfilled, hard to say where the coolant was spilling from cause I panicked and switched her off quick, I'd guess it was coming from the reservoir though, I might need a new radiator cap so.
I will take the side panels off today. top up the coolant in the radiator and reservoir bottle, burp her and see where the leak is coming from then, hope it's as simple as getting a new Rad cap.
The fan may not have been enough to keep her cooled own I had her idling too long , I'll check and see if the fan is coming on at I think it's around 104 degrees C it used to switch on.

 

Did you recently work on the coolant system? Maybe an air bubble?

 

No haven't done anything to her, just cleaned and put her in the garage for the Winter, put the trickle charger on her every month or so,
bike fired right up yesterday and just let her idle as I said, maybe too long, then she boiled and spilled her coolant,
unless the Rad cap has just packed in as Terry suggested or maybe the fan didn't kick in? I'll fill her back up with the side panels removed and see where the coolant is escaping from and if the fan is kicking in as it should at 104c/220F.

 

The new genuine Rad cap is very expensive, 19045-GBF-700 or 19045-MZ1-621
hardly worth chancing buying a second hand one off ebay though..

 

Thanks, yes I can see the photos, I will have a look for a 1990's Honda accord rad cap, when I removed the side panels I discovered the cap on the expansion tank was off so that where the coolant was forced out, rad cap is the likely culprit according to what Terry said earlier.
I have refilled her with coolant and will run her now and see what happens. New rad cap likely required though.

 

Just found one here on TEMU for 2.10 euros! it's the same part number so I think it's worth a try.
http://www.temu.com/goods.html?_bg_..._1740353564178_cqpb9yefod&refer_page_sn=10037

 

Thanks for the advice on the radiator cap. I got one from a local autoparts store, Blue Print ADH29902.
less than a third of what it would have cost me to buy the genuine Honda part from a motorcycle parts supplier.
I haven't tested it yet because I have the bike on the bench to fit stainless headers, the original headers finally had enough!

 

If the bikes cooling system was in perfect working order, could the bike be left to idle without overheating for say half an hour? especially say in ambient temps around 10c/50F?

 

Absolutely; the cooling system should heat up to the fan cycling temperature (usually around 102C) then the fan starts, temperature should creep down to around 98C where the fan will shut off, then it will creep up again until the fan cycle starts over.

If it gets to say 110 and the fan is not running then you need to take a look at the fan wiring or fuse. or maybe the blade is jammed with debris. Easy enough to jumper the fan to check the motor (connecting the wire at the radiator thermoswitch to earth should complete the circuit).

The maximum allowable temperature is around 120-odd. Any more than that and the engine needs to be shut down for some investigation.

 

Thanks Terry, that's great info, a mates bike, also a 5th gen Vfr. has had the exact same thing happen as mine but he thinks it's because he left it sit idling too long, I advised him his bike probably needed a new rad cap as well. He's not convinced.

 

Well got the bike back on the road today, the new rad cap solved the overheating problem, running new coolant now too so hopefully that problem is solved, thanks all.
Also fitted stainless headers and a new Scorpion end can, sounds great, get some more miles done tomorrow to really appreciate it.