Looking for mechanic to help
 

I've got a 2020 RX4 that I love riding, but I'm having an issue that's kept me from getting much riding done this year.


Specifically I'm getting an overheat warning on the dash (full bars & flashing on the temperature gauge). I know it's a long shot, but is there anyone in the Cincinnati, OH area who could lend me a hand figuring out the cause?


I'll pay a reasonable rate.


Barring that, does anyone know of a shop in that general area that will actually do the work? (I tried 'The Powersports Store', but they charged me $400 to kill my battery and send me home on a flat tire after keeping it for 2 months.)

An over heating issue with the RX4 should be fairly easy to diagnose.
More than likely it is just low on coolant ! the problem is when it's that low you'll need to remove the right side fairing to be able to get to the radiator.... you may be able to reach it with a funnel and hose though.... but getting that cap off will take a contortionist trick!
for me I would just pull the fearing off and then pull the radiator cap off ( when stone cold of course) and then fill the radiator with a 50/50 mixture of coolant
(DO not put in water!) these engines need the wetting agents in the coolant to transfer the heat .... once you have the coolant about 1/2" from the cap start the bike and see if you have coolant circulation...you should be able to see turbulance in the coolant in the radiator not just from the vibration of the running motor but from the flow of the coolant being curculated.....
if there is curculation your good to go ! be sure to fill the over flow tank as well up to the full mark on the tank ... if you fill it to the top it will just leak out the over flow tube!
....
the other thing that might be causing the over heating is the radiator fan not comming on.... it is supposed to kick on at 94deg centragade I think... so take it for a short spin hop off and bend down and look and see if the fan is spinning behind the radiator...
Mine is so quiet I can't hear it at all so I have to Look to see it....
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SERIOUSLY chances are it's just low on coolant you can try to fill the little coolant tank on the right side with the rubber cap on top of the fairing but it does not hold much
so you might have to re fill it 2 or 3 times with short runs in between and let the engine cool completely in between times.
....
if you do not see circulation then you have problems with the water pump. and that means a tear down ....
....I tested my radiator fan fairly easy by just idling the bike in place and watching the tempiture gauge slowly climb and when it reached 94C i kept looking at the fan motor and it finally kicked on and was working...( I could not see the fan blades any more)
my bike a 2021 would raise in temp to about 95deg C and the fan would kick on and lower the temp to about 85 deg and then turn off.... and it would cycle like that indefinitely.
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Your best bet on Motorcycles is DO THE WORK YOURSELF ! down load the manual from CSC and play the tutorials they help a great deal.... you can do it yourself !
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Bob.......

Good post Bob. Something as simple as air trapped in the system will also cause overheating.

Like they said, it's most likely low coolant level or just air trapped.
The engine should have a bolt that's there just to bleed the system.

https://www.youtube.com/watch?v=xeTg...yMechanicsKnow

Yes it's a truck but it's the same principles

You don't have to be Mechanically inclined to do simple maintenance ! but I do recomend getting an adjustable end wrench instead of trying to use a pare of Plyers !
but most of the things on the RX4 are going to be metric allen wrenches anyway but the tool kit on the RX4 should be all the tools you need really !
....
there is no doubt in my mind that some guys are better off takeing a bike to a bike place as they are absoultly hopeless when it comes to working on things... but consider this.... you have to start somewhere ! I was one of the fortionate ones who grew up with a wrench in his hand ! my Dad taught me all he could, and would relate stories of me taking apart a special Kitchen clock when I was about 4 years old to my mothers dismay.... i wanted to see how it worked ! but after getting my butt spanked and threatened a more serious butt spanking I had better put it back together .... so I did!
and it suprised my Dad so much that he would brag about that to all his friends !
HAHAHHA ! but although I am quite convinced I can fix anything, I am no good at interrior design....or nuclear physics.... or paperwork of ANY KIND ! as I don't read fast and spell like a 6th grader ! .... but I do know engines !
but not everyone does ! and that's ok.... knowing your limitations is very important
this day and age ! you don't have to be a mechanic, but it really helps to know a good one ! HA !
Most guys can handle basic maintenance and that would include flushing the radiator system.... which is just about what I outlined earlier ( except how to drain it)
.... with the radiator mounted as high as it is on the RX4 there is little chance that there will be a bunch of air in the system like we used to get on 1970's ford cars....
but I really do not know the in's and out's of the RX4 all that good.... i haven't had it That long yet.
but I will say this CSC is very good about their "tutorials"...and if they don't have what your looking for for the RX4 look at the RX3 section as there are a ton of tutorials there
and the engine is almost identical.... the RX4 is just bigger !
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Bob.....

Although it would be nice if the RX4 tool kit was all you need for basic maintenance that's not the case. You will need, at a minimum, a 3mm allen wrench just to get the plastic panels off. I'd recommend a "T" handle metric allen set because you will need them so often. Then a basic metric open/box end wrench set and you are good to go.

Peter Y.

That's correct, in most motorcycles the radiator is the highest point in the cooling system, so is quite uncommon to have air bubbles.
But since it seems he never messed with the cooling system since he got it from the dealer, who knows.
If it was my motorcycle i would just flush down whatever is in the system and replace it with some a good brand of premixed organic coolant.

Agreed ! flushing the whole system is probably the best idea anyway ! just from a maintenance point of view.... it's a 2020 model so coolant has never been changed and it has gotten very hot.... so getting rid of the coolant that is in there is a good idea !
antifreeze is a strange animal, it's not the best COOLANT in the world so they add wetting agents into it to make it transfer the heat better.... who is to tell if that wetting agent is now compromised or not ? I can't say, but I do think it's better to err on the side of safety and just replace it all !....
it is however not impossable for the water pump to be the problem ! if the coolant circulation is slower than normal it will over heat.... although the heat gauge is a joke on the RX4 on the 2021 model I can't say for the 2020 model the new TFT dash
is "Generous" as Joey at CSC told me...
but the whole over heating thing should definately be repaired as it can destroy the engine ! ....
over heating can also be caused by running too lean a mixture of fuel... which is highly unlikely.... but it could happen.....
I discovered that the factory setting for the ECU is 14.1 fuel to air ratio which is extreamily lean to begin with.... I seriously doubt it could run any leaner than it comes stock from the factory ! it's ridicously lean ! .... I changed all the settings in my ECU to 12.1 instead of 14.1 and the bike really preforms much better and runs cooler as well
i can accelerate at 70mph without having to wait for it to do so... unlike stock !
so I really expect it's just low on coolant....
and sense he hasn't said otherwise.... well, it's all mute ! LOL
....
Bob......

Sorry, had a busy week, and just now got the chance to get back on here.


In theory, the shop I tried to have do the fix checked & replaced the coolant. They said they couldn't find a physical/mechanical cause, but weren't willing/able to do anything more in depth.

I have a decently comprehensive set of tools, but when it comes to disassembling the bike to get at things, I don't have the background/experience, and I'm not sure where to start, so I'm a bit reluctant to get too deep into it without someone who knows what they're doing.

Coolant levels look right according to what CSC & the service manual says I should expect to find.

Think about testing to see if it is getting hot enough to throw a code. Could be a bad sensor. May have already been ruled out. Check Temp while overheat alert is on.

I was thinking bad sensor also. It’s too rare for a cooling system to go bad like that. Not on a fairly new bike.

here's an idea..... when the bike is stone cold...... reach up under the right side fairing
and take off the radiator cap... then stand up and see if the coolant can be seen in the radiator.... I'ed bet money those guys at the bike shop never re checked it after filling it and it's only half full....
when the radiator is properly filled it will be up to the sealing ring just under the cap area.....
if it's low put in antifreeze/coolant that is a 50/50 mix you can do that with a garden hose on a funnel or a automatic transmition funnel from the auto parts store.
I seriously doubt there is a problem with the bike just incompetence of the bike shop.
Nobody cares for your bike like you do ! do it yourself even if it pushes your comfort level !
......with the radiator cap off and the coolant just covering the fins of the radiator you can squeeze the rubber hoses to force out most of the air in the system you might spill some coolant but it is worth it to get the air out.

Edit: also the bike has a thermostat so the bike has to be warm enough for the thermostat to open before you will see turbulence/circulation of the coolant so keep that in mind.



also when putting the radiator cap back on you push down and turn it 2 clicks push down and turn it clockwise as far as it will go ( about 1/2 ~3/4 turn) if it's not on tight you will over heat and boil out the coolant....( which might have already happened because of the shop trip)
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so to re-cap take off the radiator cap fill the radiator , put the cap back on good and tight ( put it on and take it off a few times so you can tell where it SHOULD be!)
you can get to it without taking off the fairings but it's a pain !
then check all the fuzes under the seat and make sure all of them are good...one controls the radiator fan.... if it's bad it will over heat sitting there idling
....
the RX4 is a Super strong Tank of a motorcycle it will run practically forever !
but running it without coolant can destroy it in short order.
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so test the cooling system and make darn sure it is working
after you do all the above test it to make sure it's working....
on my bike I simply put it into neutral and started it and let it idle and watched the temp gauge slowly come up.....till the radiator fan kicked on.... and I watched the temp go back down... then the fan turned off and the temp slowly raised again....
I don't know what kind of gauge you have on that bike but you should be able to check in the same manor...... if the radiator fan cycles on and off like it should you are good to go and it should not over heat again.... re check the over flow tank and make sure it's full for the radiator before you take it for a run....
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hope that helps...
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Bob.......

One way to get air bubbles out is to position the bike so that the radiator cap is at the high point of the radiator, i.e. uphill. Start the bike with a cold radiator, and the radiator cap off. If the coolant is circulating, the bubbles will get to the uphill cap and burst. When the coolant gets too high, put the cap back on. Might have to repeat one or two times for a complete job.

If your rad cap is on the right, then just putting your bike on the sidestand would qualify as uphill.

Any update??