Topping up coolant reservoir frequently -- possible leak?

mgorven · August 16th, 2013, 10:21 PM

I did a valve adjustment three weeks ago for which I removed the radiator and thermostat. Since then the coolant reservoir has been below the full mark when I've checked it weekly, and I've had to top it up each time. Before the valve adjustment the reservoir was always full and never needed to be topped up.

Should I be concerned about this and start looking for leaks? Or is this normal as long as it doesn't drop below the empty mark? Should I even be trying to keep it at the full mark?

cuong-nutz · August 18th, 2013, 07:45 AM

Perhaps you did not bleed all the air out into the system. Also it's possible that your coolant overflow cap is not sealing properly when closed. If that is the case coolant will leak out of the cap if you we're to have the bike parked on its kickstand. I do not know how much you are losing but I would check that first. Another common cause of leaking after valve adjustments is the o ring for the coolant tube atop the head of the engine is worn out and will leak coolant into the head or out the back of the motor depending if the valve cover gasket is sealing properly or not. The o ring is the same size as the small one for your oil filter. Also make sure that are your coolant drain bolts (one below your water pump and one on the cylinder block under your exhaust header/manifold) are torqued down. Of course check your coolant hose clamps at the radiator and so forth.

mgorven · August 18th, 2013, 10:10 AM

It's been loosing 50-100ml per week. I didn't count the very first topup because that was due to air bleeding.

I took the right fairing off yesterday and ran the engine a bit, and spotted a leak at the inlet to the thermostat and possibly at the bottom port of the reservoir. I re-tightened the hose clamp and it seems better, so I'll see what my coolant level is like next weekend.

mgorven · August 26th, 2013, 01:29 PM

Coolant didn't need to be topped up a week later (still at Full level), so it must have been the hose clamp.

August 16th, 2013, 10:21 PM	#1
mgorven ninjette.org member Name: Michael Location: Sunnyvale, CA Join Date: Mar 2013 Motorcycle(s): 2011 Ninja 250 Black Posts: 30	Topping up coolant reservoir frequently -- possible leak? I did a valve adjustment three weeks ago for which I removed the radiator and thermostat. Since then the coolant reservoir has been below the full mark when I've checked it weekly, and I've had to top it up each time. Before the valve adjustment the reservoir was always full and never needed to be topped up. Should I be concerned about this and start looking for leaks? Or is this normal as long as it doesn't drop below the empty mark? Should I even be trying to keep it at the full mark?

August 18th, 2013, 07:45 AM	#2
cuong-nutz RIP Alex Name: Cuong Location: Houston, TX Join Date: Apr 2011 Motorcycle(s): '10 250r, '09 265r Posts: A lot. Blog Entries: 2	Perhaps you did not bleed all the air out into the system. Also it's possible that your coolant overflow cap is not sealing properly when closed. If that is the case coolant will leak out of the cap if you we're to have the bike parked on its kickstand. I do not know how much you are losing but I would check that first. Another common cause of leaking after valve adjustments is the o ring for the coolant tube atop the head of the engine is worn out and will leak coolant into the head or out the back of the motor depending if the valve cover gasket is sealing properly or not. The o ring is the same size as the small one for your oil filter. Also make sure that are your coolant drain bolts (one below your water pump and one on the cylinder block under your exhaust header/manifold) are torqued down. Of course check your coolant hose clamps at the radiator and so forth. __________________________________________________ HalfFast Racing Team Serving Greater Houston Area Riders:WFO Riders MotoHouston HPC CMRA Ride Smart Fastline Lone Star Track Days

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August 18th, 2013, 10:10 AM	#3
mgorven ninjette.org member Name: Michael Location: Sunnyvale, CA Join Date: Mar 2013 Motorcycle(s): 2011 Ninja 250 Black Posts: 30	It's been loosing 50-100ml per week. I didn't count the very first topup because that was due to air bleeding. I took the right fairing off yesterday and ran the engine a bit, and spotted a leak at the inlet to the thermostat and possibly at the bottom port of the reservoir. I re-tightened the hose clamp and it seems better, so I'll see what my coolant level is like next weekend.

August 26th, 2013, 01:29 PM	#4
mgorven ninjette.org member Name: Michael Location: Sunnyvale, CA Join Date: Mar 2013 Motorcycle(s): 2011 Ninja 250 Black Posts: 30	Coolant didn't need to be topped up a week later (still at Full level), so it must have been the hose clamp.