Radiator cap geyser

ubuntufan

Joined
Oct 25, 2013
Messages
9
Location
denmark
Bike
ST1100
Hi ST1100 Techs

My ice cold ST1100 radiator makes a geyser when I rev it 2-3k rpm. Can someone please try this on their st1100 to see if this is normal ?

I changed the coolant as part of my bike service.

http://youtu.be/DnNYcnHr3zY

Thanks
 

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It would be normal that coolant flushes through the bypass (a ~2mm bore at the rearward side of the radiator neck, but the vid doesn't show that) while the thermostat is till closed.
If you start the engine without blipping the throttle (just let it idle along), that narrow coolant jet is clearly visible.

If it always gives a full flow/not increases while the coolant warms up, likely that the coolant thermo is stuck in open...
 
Last edited:
That does look normal to me. I have seen that with my system. There is enough force of coolant just from the bypass hole, when the engine is reved, to cause an overflow. If the thermostat is stuck open, the temp gauge will not rise very high at all in the cold weather. If, once the cap is on, you get normal readings from the gauge, I'd say you have nothing to worry about.
 
Normal. Don't rev the engine with the radiator cap off.

You could let the engine run to check that the thermostat opens when the coolant gets hot enough.

John
 
John OoSTerhuis said:
Normal. Don't rev the engine with the radiator cap off.

You could let the engine run to check that the thermostat opens when the coolant gets hot enough.

John
Click to expand...

I think John should have added - replace the cap BEFORE shutting down the engine, or you could have a serious geyser from boiling coolant.
 
Thanks for the feedback. Comforting that it seems normal. I will look for the 2 mm bore to verify. And i have a new genuine honda cap :biker:
 
Slasher said:
The thermostat is a cheap fix if you want to eliminate is as a possibility. You can get a Stant brand at any auto parts store that works perfectly. It was the first thing I replaced on my 1100 after the seller told me "it was cold natured". The Stant # is 13868. http://m.advanceautoparts.com/mt/sh...w_wcB&un_jtt_v_cookiecheck=on&un_jtt_redirect

If your cap has gone bad, you can also use a Stant replacement #11233
http://www.amazon.com/gp/aw/d/B000C7YQBA/ref=redir_mdp_mobile?pc_redir=T1
Click to expand...


+1 . Been using both ( thermostat & cap ) for the last two years without any problems. And you can't beat the price.
 
ubuntufan said:
Thanks for the feedback. Comforting that it seems normal. I will look for the 2 mm bore to verify. And i have a new genuine honda cap :biker:
Click to expand...

You won't be able to see that hole in the thermostat, unless you disassemble the housing, which you don't need to do, because there is nothing wrong.;)

Another question is - did you use the correct coolant?
 
Here we don't have the fancy OAT, HOAT.. So I simply use oldfashioned ethylenglycol (1,2 ethandiol) should be OK as I understand.
 
ubuntufan said:
Here we don't have the fancy OAT, HOAT.. So I simply use oldfashioned ethylenglycol (1,2 ethandiol) should be OK as I understand.
Click to expand...

Can't comment on OATs or HOATs ?? but it is important to NOT use any coolant that contains silicates as cleaning agents, as they will clean your water pump seal right outta there.
 
Bush said:
...it is important to NOT use any coolant that contains silicates as cleaning agents...
Click to expand...
+1...
If the label does not explicitly say [SILICATE FREE] (or [silikat fri] in Denmark), don't use the sludge on the ST...
 
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