Low coolant in new MXR

[rayivers]

I just checked my MXR's coolant level after reading Oded's recent overheating post, and as far as I can tell my bike is bone-dry (no coolant 6" down fill pipe). According to the manual coolant filling takes about an hour, so maybe with the new bikes/prices the assembly line got busy and this step was sometimes left out, who knows. I'll be calling Alta later today and will report back after. UPDATE: There was definitely coolant in the system, but the level was below the bend in the fill pipe.

Ray

 

[Judaslefourbe]

Hi there.
I have been lurking around but I figured I would jump since it seems there are questions about the cooling system.
While it is possible this step was missed on your bike, it is extremely unlikely; did you see any coolant pooling under the bike?
The reason you cannot see the coolant in the hose is because we leave enough room for expansion when the coolant gets hot.
If it makes you more comfortable, you could add 50/50 ethylene glycol coolant (we use Prestone on the line) but make sure you leave some room for expansion.

PS: The system is setup for 750mL of coolant
PPS: Yes, I do work at Alta Motors

 

[Philip]

Welcome to the Forum, Judaslefourbe! I am thrilled at having our own resident Alta guy!

Thank you for helping us figure things out about out Alta bikes.

 

[rayivers]

Thanks very much for this info, I really appreciate it.

While it is possible this step was missed on your bike, it is extremely unlikely; did you see any coolant pooling under the bike?

No, no coolant spillage at all. I haven't actually ridden the bike yet, only turned it on briefly.

The reason you cannot see the coolant in the hose is because we leave enough room for expansion when the coolant gets hot.

OK, that's good to know. A couple questions... is the fill adaptor shown on page 75 on the manual actually available at the Alta website as stated? and does "the bottom of the fill port" refer to the top curved section under the cap? The manual text 'the coolant level should be visible in the filler hole' (p. 16) led me to believe I wouldn't need a dipstick type thing to find the level with the system cold.

Ray

 

[Judaslefourbe]

The adapter is available through the dealer of your choice: part number 7703032-00 (MSRP is $46.80). I would recommend getting the funnel as well so you can just let the bike do the work for you (the funnel will hold the whole volume). PN 7702897-00, MSRP $68.55.

However I would recommend you actually check if there is coolant in the bike by playing with the drain plug located at the rear of the chassis (don't unscrew completely so you don't lose much coolant) and then top off a bit for the loss from the operation.

 

[rayivers]

Thanks for those part numbers - I'll add them to my current order in progress.

Will loosening the drain plug 'break siphon' (or whatever the term is) and start the pump cavitating during refill? I ask because a fill procedure requiring a sealed funnel entry, clamped-off vent hose, & pump activity must create at least some amount of vacuum?

Ray

 

[Judaslefourbe]

No, it will be fine: the pump will circulate the air until it ends up in the expansion chamber.

 

[rayivers]

I loosened the drain plug (USA 3/8" hex, on the main bulkhead casting above the RH swingarm bearing area) and a few drops of green coolant came out, so there's at least some in there now. Can I just top it up, or do I really need the filling items above? When will I know when the filling procedure is over and I can turn off the pump? Will I need to run the pump for the full hour to make sure all air is purged? Sorry for all the questions, but this is a critical item & the manual is kinda vague.

Ray

 

[Judaslefourbe]

You can do it 2 ways:
1 - you can drain all the coolant and refill with 750mL to make sure you have the proper amount.
2 - you can top off until you see the coolant in the port then drain a bit to leave room for expansion.
The tools are not necessary, they would just make your life easier.

 

[snydes]

I just checked mine, it was obvious when I removed the fill plug that there was coolant in the system, but the level was not visible. I took a new pipe cleaner and gently stuck it down in a bit to see if the level was just out of sight and it didn’t appear to hit the top of the coolant level. I then added exactly 1 fl. oz (29.57 mL) coolant and it went immediately to the just below the threads of the fill plug. I then removed a little till it was just visible. So I added maybe .5 fl oz. That fill hose is not very big and sort of flattened out so it’s going to hold very little coolant. I think the issue is the manual says about the coolant should be visible with the plug removed, and it might only be down a few mL’s but be way out of sight. At least that’s how mine was.

Keep calm and Zaaap!

Steve

 

[Philip]

Keep calm and Zaaap!

Zaaap is the new Braaap!

 

[Elite Motorsports]

It has been our experience that the coolant pumps can get a little noisy after some use. I believe you can purge the system to remedy (I don't have the procedure and maybe Judaslefourbe can confirm this), but the scratchy noise is pretty normal.

 

[rayivers]

Thanks to all for the help! I added @ 29ml of coolant with a 10ml syringe, after which the level was just visible down at the bend of the coolant passage (as per the manual). I then replaced the cap and ran the pump; unlike earlier, this time the frothing cavitation noise quickly changed to the steady low whine in the YouTube video. I don't have a N/mm torque wrench, so I tightened the cap what I'd call 'very strong finger tight' (about what it felt like when I loosened it the 1st time), which was somewhere between 1.4 and 1.8 Nm (manual says 1.5 Nm, 1.1 ft/lb). I then removed the cap and inspected the O-ring (perfect), lubed it again with coolant, then put it back on same as before.

I'd suggest to Alta they either a) increase the coolant level slightly so it can be checked, or b) edit or remove 'The coolant level should be visible in the filler hole' from page 16 / section 4 of the manual. An ideal solution would be to make the top filler-tube section from a hi-temp clear material, as it's easily visible thru the top RH frame opening; one quick look would give you level / coolant clarity / circulation info.

Ray

 

[Judaslefourbe]

Thank you for your input. We are working actively on fixing the service manual, and this one is definitely on the list. Hopefully we can get it done very soon.

 

[Philip]

The name of this thread should probably be changed to 'Low coolant in new MXR'.

Done.

You can edit your own threads' titles yourself as well.

 

[rayivers]

OK, I see it... the three dots / 'More options' / 'Edit thread' in the upper RH corner. Thanks!

Ray

 

[Philip]

I checked the coolant on my MX. It dribbled out twice before, so I thought it could be low.

I did not see the coolant initially, so I measured and poured in 40cc. It almost all immediately leaked out.

I then started the pump and the level went down, low enough so that I could not see it anymore. I measured about 40cc this time and poured it in. The pump immediately got quieter. I turned off the pump and saw some coolant in the hose. That's it. My coolant might have been a little low but not by much.

 

[Philip]

The new MXR has not a black plastic but a red anodized aluminum coolant plug with a WARNING message in it. This must be a 1% of the 20% all-new parts. It barely took 10cc of coolant until I could see it.

 

[rayivers]

My coolant might have been a little low but not by much.

The thing is... unlike every liquid-cooled ICE bike I've seen, the Alta pump is up high and moves coolant primarily by suction rather than pressure. This setup increases the likelihood of coolant cavitation and foaming, which in turn can lead to poor heat transfer, boiling, etc. IMO it's critical that the pump always operates completely filled with non-aerated coolant, which may involve only a small change in level. If the pump makes any noise other than a steady low-level whine (gurgling/churning/etc.), I'd add some coolant till it sounds right. This is much easier on the pump as well (the Wikipedia cavitation entry is worth a quick read).

Ray

 

[Philip]

Yes, it all makes sense. Thank you, Ray.

I forgot to mention. The coolant on my MX became a bit foamy while I was running the pump. Cavitation might be hard on the pump, but aeration is definitely not good for heat transfer. Keep that coolant level always in sight!