Coolant Leak

[mikesim]

If you have difficulty locating the leak, clean the engine off and then run it 'til it's warm. Then take some talcum powder and sprinkle it all over the engine in the area that you see the leak occurring . The leak will be obvious.

Mike

 

[cliffh]

I have just replaced the 2 'O'-Rings on the coolant pipe between the cylinders on my NT700VAA. It is relatively easy once you know the trick to getting the 'O'-rings off and on (discussed in the video below).

My YouTube video discussing how to change the 'O'-Rings:

Note, the video assumes you know how to remove the fairing...

Great information and enjoyed taking the video ride with you while you explained the procedure.

 

[RedNigel]

I went home t lunch and pulled the kleenex i had between the cylinders and under the little pipe. It was clean as a whistle.
Then I removed the right side mid cowl and checked the overflow reservoir, which appeared to be empty. I topped it off with OEM type 2 and closed the tank.

MY question is: If there is a coolant deficit in the engine/radiator, will it pull from the overflow to top itself up?

BTW, the bike is running as usual and not getting hot.

 

[mikesim]

Yes, as the engine cools a vacuum is created in the radiator which will draw coolant from the coolant recovery tank. Now, the next time you have the mid cowl vent off, look for the radiator cap. You will see that the only thing preventing you from removing the cap is a piece of plastic that is part of the right side cowl. The next time you have the right side cowl off, take a hot knife or Dremel tool and cut away that piece of plastic that prevents you from moving the cap. Doing this, gives you room (not much) to get your hand in there and remove the cap when necessary without having to remove all the tupperware.

Mike

 

[JQL]

Yes, as the engine cools a vacuum is created in the radiator which will draw coolant from the coolant recovery tank. Now, the next time you have the mid cowl vent off, look for the radiator cap. You will see that the only thing preventing you from removing the cap is a piece of plastic that is part of the right side cowl. The next time you have the right side cowl off, take a hot knife or Dremel tool and cut away that piece of plastic that prevents you from moving the cap. Doing this, gives you room (not much) to get your hand in there and remove the cap when necessary without having to remove all the tupperware.

Mike

The cooling system on my 2010 NT700 (125,000 miles - 200,000 km) had 3½ different problems:

1. Leak from O-rings between the cylinders
2. Thermostat not opening
3. Leak from the pipe between the thermostat housing and the top of the radiator where it joins the thermostat housing.
4. (½)The radiator cap was past it's prime though still functioning (just). I replaced it.

Once the Tupperware has been removed (a full service opportunity?), the work to replace all these parts took about half an hour. The problem was that I needed to order the parts and had to wait about 2 weeks for them to arrive. If memory serves, the cost of all the parts (I used OEM) was less than $100.

A few of things to note:

• While waiting for the parts to arrive, flush the radiator with distilled water. As the coolant in my NT has been changed every 18 months-ish, it was clean - yours may not be.
• The drain bolt on the right side of your motor (near the pipe connecting the cylinders) will most likely be seized. It doesn't need to be removed.
• The drain bolt of the water pump is a special bolt so don't damage or lose it. Replace the washer. Torque is not a lot (9 ft-lb).
• The radiator cap can be very tight to get off and put on - make sure it is replaced properly - DAMHIK.
• Order the thermostat gasket at the same time as the thermostat as the old gasket will be toast - guaranteed.
• The bolts on the thermostat housing are only 7 ft-lbs. Be gentle!
• The thermostat just pulls straight out from it's housing once the cover is removed.
• The small pipe from the thermostat housing to the radiator was out of stock virtually everywhere (found at https://cmsnl.com).
• When replacing the hose clamps, the manual states tighten them until they sink 1 mm into the hose.
• Ordinary plumbing O-rings of the correct dimensions will probably be OK to replace the O-rings between the cylinders.
• Watch the video (above) before replacing the O-rings - it will save you hours, honest!
• When replacing the coolant (1.8 litres), get the correct stuff (no silica and for aluminium engines) but try to find one with a darker colour - easier for checking the expansion tank level.
• After doing the work, refill the radiator but only fill the expansion tank to the bottom mark. Take the bike for a good run and get the fan to cycle, allow to cool, then top it up if necessary (you may find the expansion tank is about half full!).

 

[RedNigel]

I took the bike and rode it in all kinds of conditions yesterday. Stop and go surface streets, medium speeds and 85-90 on the freeway. Ambient temps in high 70s and low 80s, the engine seemed to operate normally; Fans engaged at the usual times. No visible coolant leaks thus far

 

[mikesim]

I took the bike and rode it in all kinds of conditions yesterday. Stop and go surface streets, medium speeds and 85-90 on the freeway. Ambient temps in high 70s and low 80s, the engine seemed to operate normally; Fans engaged at the usual times. No visible coolant leaks thus far

Excellent! How much did you have to add to replace the lost coolant?

Mike

 

[RedNigel]

Excellent! How much did you have to add to replace the lost coolant?

OK so that was a week ago Sunday

No leaks showing thru the week. Then this afternoon I see fluid on the floor again! I pulled the right side tupperware and right away I see a small mound of yellow powder on the fram directly below what I assume is the thermostat housing? (where the radiator cap is) Then i see a streak where coolant is leaking either from the radiator cap or the overflow line leading back to the OF reservoir. (see pics) But what is bugging me is A: if that is truly my leak how is it migrating to the other side of the bike? B: Why is my radiator slp full and my res full still?

 

[JQL]

Sounds like you need to replace the radiator cap, short pipe from the radiator to thermostat, thermostat and gasket as well as the O-rings. Oh, and flush the cooling system to get rid of the grunge...

Once you've got the tupperware off, replacing the O-rings, Thermostat and radiator cap will take you about half and hour. Flushing the system - a lot longer. I'd do it without the thermostat in place to really clean out the system

 

[RedNigel]

When looking at the Partzilla website I see 4 NT700 models. How do I know which one is mine?

NT700V 4AC - NT700VA	VT1300CSA A - SABRE ABS
	NT700V AC - NT700VA	VT1300CT A - INTERSTATE
CBR600RA AC	NT700VA 4AC - NT700V	VT1300CT AC - INTERSTATE
CBR600RR 2A	NT700VA AC - NT700V

 

[ST1100Y]

When looking at the Partzilla website I see 4 NT700 models. How do I know which one is mine?

There even more

https://www.cmsnl.com/search/?section=all&q=nt700&tab=

 

[mikesim]

What color is the coolant on the ground? The only thing untoward that I see on your pic is a yellow knurdle of "stuff" hanging from the t-stat housing. As far as the leak migrating from right to left? I'm assuming that you parked in on the side stand which would cause a leftward lean, thus the coolant draining leftward.

When looking at the Partzilla website I see 4 NT700 models. How do I know which one is mine?

NT700V 4AC - NT700VA	VT1300CSA A - SABRE ABS
	NT700V AC - NT700VA	VT1300CT A - INTERSTATE
CBR600RA AC	NT700VA 4AC - NT700V	VT1300CT AC - INTERSTATE
CBR600RR 2A	NT700VA AC - NT700V

Clay, for the parts you will need, any one of the NT's parts lookup will work.

Mike

 

[RedNigel]

I'm assuming that you parked in on the side stand which would cause a leftward lean, thus the coolant draining leftward.

Yes but how would it make it from that part of the frame to the left side of the crankcase? and why did it take a week? I have one more thing I want to check; Since the radiator appeared to be overfull, and I mean right to the bottom of the cap, but the OF reservoir level remained unchanged... I am going to pull the OF hose from the radiator neck and blow thru it to make sure there are no obstructions to the tank. I say this because the radiator is so full and I think where you see the buildup on the piece going from the neck to the OF hose (2nd smaller pic) I'm wondering if coolant is being forced from under the rad cap. and then somehow migrating to the left side of the bike, even though i cant see a path that accommodates the fluid to travel such a distance

 

[mikesim]

Clay, it's not uncommon to have a plum full radiator with a coolant recovery system. Also, your bike, like mine, is no longer a spring chicken and it wouldn't be out of the question to have a leaking radiator cap.

Mike

 

[RedNigel]

Clay, it's not uncommon to have a plum full radiator with a coolant recovery system. Also, your bike, like mine, is no longer a spring chicken and it wouldn't be out of the question to have a leaking radiator cap.

Mike

Yep. I'm replacing the radiator cap, and that short hose just in front of that that goes to the radiator. And while I'm there I'm going to replace the 14 year old thermostat and gasket. Parts on order; just waiting

 

[JQL]

Yep. I'm replacing the radiator cap, and that short hose just in front of that that goes to the radiator. And while I'm there I'm going to replace the 14 year old thermostat and gasket. Parts on order; just waiting

While you're waiting, whip out the thermostat, replace the cover and flush the system with denatured water (1.8 liters) so it's ready for the parts.

 

[RedNigel]

denatured water

So in American does 'denatured' mean "distilled" LOL

 

[mikesim]

So in American does 'denatured' mean "distilled" LOL

I'm thinking it does, but denaturing a substance and distilling a substance are different.

Mike

 

[JQL]

So in American does 'denatured' mean "distilled" LOL

Not quite and the difference is fairly important for cooling systems.

Distilled water contains a small amount of minerals. Denatured water has no minerals.

I believe that Denatured water may be called Deionized water in the US.

 

[mikesim]

DI water is not as readily available in the US as is distilled water. For the purpose of flushing your cooling system, distilled water is just fine. If you buy full strength coolant that must be diluted, use distilled water as well, not tap water.

Mike