RT running hotter after coolant flush - did I miss something?

[computek]

2012 998 RT-S . Guys, I flushed my coolant just to ensure it had been done. I burped it with the cap off for quite some time and topped it off as needed. I put about 50 miles on it since. Anyway the analog guage now reads one bar higher than it did before. The fan comes on as expected. Did I miss something while burping? I am at a loss. Does not seem to be getting too hot.
Thanks in advance!

[Peter Aawen]

What coolant did you put in after the flush??

Any differences in the coolant type/composition/concentration can cause this sort of 'different running temperature' indication; but then the Spyder analogue temperature gauges, especially those on the pre-2014 Spyders, are notoriously fickle &/or wildly inaccurate at best! AND like most modern motor vehicles, they're damped somewhat to avoid scaring the un-aware punters; meaning that they tend to rise rapidly on starting up; quickly reach a 'mid-point' indication; and then just never move off that! When in reality, your coolant temperature WILL be rising and falling somewhat as the thermostat opens & closes; the fan cuts in & out; the air flow thru the radiator varies with road speed; and the engine load varies et al! So your OEM gauge isn't ever really going to be showing you anything that's truly accurate in terms of the coolant's current temperature much beyond 'it's still OK'; and if you're lucky, it'll move off that 'somewhere in the middle' mark to show you any rapid increase in coolant temperature before it's too late to avoid too much engine damage - but it'll likely only do that IF you're lucky!

So if you're sure:

• you flushed the cooling system thoroughly;
• that you re-connected everything properly & there's no leaks (not even in the overflow reservoir);
• that you've got the right type/concentration of fresh coolant in there now;
• that you've 'burped' the system properly and got all the unwanted air pockets & trapped bubbles out;
• that the fan is working & the radiator fins are clear; and
• that the reservoir cap is still working to maintain the correct pressure...

then really, unless you want to start playing around with sourcing & checking your system with a truly accurate temp gauge & pressure tester etc. then you should probably just....

Ryde More, Worry Less!

Just Sayin'

[Mikey]

You may still have a bubble in there, I know some machines are hard to burp, I've seen times with snowmobiles you have to get the front in the air then get the rear in the air to get it out. They do have a tool that you can fill the system under pressure, and it forces the air out and pushes the fluid in its place. I have also seen a tool that puts the system under a vacuum and pulls the fluid in that way. Have you got any STEEP hills or banks around to park on and let it run awhile?

[Bfromla]

Have been advised to have as steep as possible, has some funny angle bends In system.

[BajaRon]

I would agree that you've still got air in the system as your most likely issue. Changing coolant shouldn't make much difference. Running more than 50% coolant will start to drop efficiency. Most coolants actually don't transfer heat as well as straight water. A 40%/60% mix can drop you as much as 5 degrees f. Still, probably not a full bar on the gauge.

Get it up to operating temperature with the cap on but not sealed. This will keep the system unpressurized with full flow through the thermostat. Run at high RPM for a few seconds and then idle down again. Do this a few times keeping an eye on the reservoir so you don't get overflow. Not a guarantee, but could help.

[computek]

Great advise so far. Bike has Genuine Honda M/C 50/50 in it now. I will retry the burping again in the morning. The front door is currently on ramps as I just finished RLS cat delete, web board install, and did the heat vent recall.

Front wheels on ramps. Dang phone…..

[computek]

Peter, I flushed it a good half hour with the garden hose after a 20 minute wait after a ride shutdown. I used Genuine Honda 50/50 coolant that I use in my GoldWings.

[computek]

Well as a follow up I burped it again for about an hour. It never boiled over with the cap off but a lot of bubbles came up (not small, about 1/4 with a few bigger) while I had it up on ramps. I seem to have gained about 1/2 a square bar on the gauge but still not running at 1/2 gauge range like it was originally. It does not seem to be overheating. It now has too much coolant in the reservoir but it's been my experience that those things will self level out eventually. And I know I dont have a leak so that is a plus.

[BLUEKNIGHT911]

Well as a follow up I burped it again for about an hour. It never boiled over with the cap off but a lot of bubbles came up (not small, about 1/4 with a few bigger) while I had it up on ramps. I seem to have gained about 1/2 a square bar on the gauge but still not running at 1/2 gauge range like it was originally. It does not seem to be overheating. It now has too much coolant in the reservoir but it's been my experience that those things will self level out eventually. And I know I dont have a leak so that is a plus.

On my 14 RT I over-filled the Reservoir (on purpose) .... and it purged the excess without any help from me .....

Because it is difficult to see where the level is - I recommend OVER-FILLING it .....Mike

[computek]

I agree, it's too hard to tell how much is in there. I had to stick an led flashlight down behind it when I checked it. It was on the full line but like I said I burped it anyway. I wish it had returned to normal but I'll take what I get.

[Peter Aawen]

I agree, it's too hard to tell how much is in there. I had to stick an led flashlight down behind it when I checked it. It was on the full line but like I said I burped it anyway. I wish it had returned to normal but I'll take what I get.

If you got some improvement thru burping it a bit more, but the gauge is not back to where you'd like it to be, you might want to try 'burping' it again. I know that there are a few people besides myself who've done this a number of times before getting the desired result - and we've got more air bubbles out each time!

Our local radiator specialist practices and even recommends to those doing it themselves that you do the 'burping' thing at least twice, or to continue doing 30 min 'burp' sessions until you stop getting improvements in the indicated temperature each time, just to be sure you've got all the air out!! And he's right, cos if you DO still have trapped air pockets in there, who's to know where they'll end up &/or get trapped again - if that happens to be somewhere critical, like around the temp sensor, or forming a block of cavitation in the coolant pump that stops it from functioning correctly & circulating sufficient coolant, you might do a WHOLE LOT of damage very quickly!!

So if you're still concerned &/or you think you might still have some air bubbles trapped in the cooling system, then raise the front of the bike as high as you can, remove the reservoir cap, and then making sure that the reservoir never empties of coolant, run your bike at a fast idle for at least 30 minutes to try and purge all those bubbles!!

You should try to make sure that the thermostat cycles open AT LEAST TWICE during each 'burp' session, but it is a bit hard to tell with these modern temp gauges that don't really show the true changes of cooling system temperature as the thermostat goes thru it's open/cooling & closed/warming cycle! Hence the 30 minutes of fast idle Or if you prefer, you could always leave the reservoir cap 'on' but not fully tightened down (ie, clipped onto its first latch so that it's still just a bit loose but it can still vent excess air/pressure readily. ) and then go on a gentle ride of about the same duration, spending at least some of that time running in lower gears at higher revs in an effort to ensure the coolant temp increases and the thermostat cycles... Apart from risking losing the reservoir cap, the only real drawback of the 'ride' method is that you can't readily see the reservoir to check the level and top up as necessary; and as air bubbles work their way out, the coolant level WILL drop!! So you need to be very careful if you use that method!

Good Luck!

[computek]

If you got some improvement thru burping it a bit more, but the gauge is not back to where you'd like it to be, you might want to try 'burping' it again. I know that there are a few people besides myself who've done this a number of times before getting the desired result - and we've got more air bubbles out each time!

Our local radiator specialist practices and even recommends to those doing it themselves that you do the 'burping' thing at least twice, or to continue doing 30 min 'burp' sessions until you stop getting improvements in the indicated temperature each time, just to be sure you've got all the air out!! And he's right, cos if you DO still have trapped air pockets in there, who's to know where they'll end up &/or get trapped again - if that happens to be somewhere critical, like around the temp sensor, or forming a block of cavitation in the coolant pump that stops it from functioning correctly & circulating sufficient coolant, you might do a WHOLE LOT of damage very quickly!!

So if you're still concerned &/or you think you might still have some air bubbles trapped in the cooling system, then raise the front of the bike as high as you can, remove the reservoir cap, and then making sure that the reservoir never empties of coolant, run your bike at a fast idle for at least 30 minutes to try and purge all those bubbles!!

You should try to make sure that the thermostat cycles open AT LEAST TWICE during each 'burp' session, but it is a bit hard to tell with these modern temp gauges that don't really show the true changes of cooling system temperature as the thermostat goes thru it's open/cooling & closed/warming cycle! Hence the 30 minutes of fast idle Or if you prefer, you could always leave the reservoir cap 'on' but not fully tightened down (ie, clipped onto its first latch so that it's still just a bit loose but it can still vent excess air/pressure readily. ) and then go on a gentle ride of about the same duration, spending at least some of that time running in lower gears at higher revs in an effort to ensure the coolant temp increases and the thermostat cycles... Apart from risking losing the reservoir cap, the only real drawback of the 'ride' method is that you can't readily see the reservoir to check the level and top up as necessary; and as air bubbles work their way out, the coolant level WILL drop!! So you need to be very careful if you use that method!

Good Luck!

Thanks Peter! I will give it another go in the morning when it's cold outside (low 40's). Hopefully another round will yield a good result. I am almost done rehabbing/modding this RT (low miles but a neglected baby) and will be looking forward to many, many miles of smiles to come!

[Mikey]

I would say, ride it like you stole it and just keep an eye on the tank, when the air comes out the fluid replaces it. You're going in the right direction.