Fun & games with coolant level...

[RichUK]

Just to recap... last year I had several coolant hose leaks but the reservoir wasn't dropping so I thought they couldn't be too serious.
Then I noticed my radiator was down a couple of inches and as it was at the end of the season I just moth balled the bike until this year.

In Spring I changed the hoses, cap & screw type hose clamps.
That was fine for a couple of runs but then it started leaking again, which must have been the clamps settling on the hoses as nearly all of them took about 1/2 a turn to become tight again.
No visible leaks now.

A couple of weeks ago whilst looking into some other issues I noticed that my reservoir was at MAX (which is where I'd filled it to) but my radiator was down to below fan switch.
So with the cap off I pressurised the reservoir which forced all that coolant in to fill the radiator again, I left the reservoir empty.
I also tilted the bike to the left and it gurgled a bit and the level dropped a little more, so I topped that up.
Until tilting the radiator was dropping while just sitting but after tilting and filling it stopped dropping when left.

A few days ago I had the first ride out since and it pushed a small amount of coolant out into the reservoir, enough to go just up to the MIN marker, but when it cooled it didn't pull it back into the radiator.
That must mean there's still air in the system right?

What should I do now??

Ride again to see if it pumps more out.
Undo the rad cap and top up the level again.
Try to elevate the front end with the engine running and up to temperature (thermostat open)?

[Willh]

A proper burping requires the front end in the air. A good long wheelie works for me.

[No. 47]

As per my post on your earlier thread, get that front wheel up..........

[RichUK]

When I filled it I did it in the Abba stand with the rear wheel out.
I suppose with the leaking hose clamp issue air could have gotten drawn back in and thus trapped in there.

So I guess it's time for another ride on the Abba stand.

[RichUK]

Did this yesterday, bike on stand, rear wheel out, front as high as possible.

Got a little more coolant in and ran the engine until the thermostat opened, topped up again then on with the cap.

Result!
As the engine cooled it started to suck back from the reservoir.
Gonna do it again today whilst it's still on the stand just so I can see how much it pushes out when up to temp.

Plus I've got to change the bearings in the rear sprocket carrier so not in a rush to take back off the stand.

[mojodog]

Don't forget to open the burp screws, upper left on the radiator and upper screw on the water pump. Raise the front wheel, remove radiator cap and wait for the air bubbles to stop. Refill

[RichUK]

OK, maybe she isn't sorted just yet....

Went out for ride yesterday and it was hot.
1st stage (up to the first stop off) the coolant went up to just over the MIN marker on the res, which is as it did last time when testing in the garage.
2nd stage involved more traffic initially (multiple fan events) and then a spirited ride on back roads home.

Got home and tank is now up to MAX, checked this morning and it's still at MAX.
Took the rad cap off and air is drawn in and the radiator is down a couple of inchs again so I guess there wasn't enough vacuum to drawn the coolant back in - rats!

So I'm thinking it can't have been fully burped.
I guess I can't get it high enough on just the ABBA stand. I'm gonna have to rig something up using a ramp and my van to ensure the front wheel really is over 50 cm (ABBA stand got it to only 45 cm difference I think), and then go through the whole bleeding process again.

[RichUK]

Well I did it again, this time using a half plank and some blocks. Got the front wheel a 50cm off the ground, did all the burp screws, set the res at MIN.
Started and idled to fan switching on and left to cool - level didn't change.
Took her for a run today which was a good test, lots of traffic, lots of fan events. Temperature gauge was above half & sometime 3/4 way up the bars.
The res is now at MAX it isn't dropping as the engine cools.

Engine luke warm so just took the cap off and there might have even still been pressure in there!

There is trace of something on the surface when I shine a torch in the radiator filler, could be oil but could also just be crap, almost like dust.

Anyway, I'm now thinking it has to be a head gasket... what else could cause this?

Soo pissed off with this bike at moment..

[RichUK]

What do you guys think, are there anymore tests I can do or is now likely I've got a gasket gone (or a cracked head)?

Seems it only blows into the coolant when the engine is hot, and the hotter it gets more it does it.
Also the engine need to be under load, idling doesn't seem to do it, or maybe idling does do it but it's happening so slowly that it not noticeable until after several hours of riding.

[No. 47]

Again, don't think you symptoms necessarily indicates blown head gasket, ie no bubbles in coolant with radiator cap off and engine running and no blow out when engine revved (?) - if the system is fully burped, and based on what are saying now, my guess is that it's dodgy radiator cap that's not allowing connection between radiator and expansion tank as radiator pressure/temp. drops.

[RichUK]

Ok - see vid and tell me what you think pls.

Vid starts when the engine is up to temperature and thermostat opened, before that it was pretty calm in there apart from a few little bubbles.

https://youtu.be/tan5EuPyqkc

Is this normal for an SD that has air trapped or is it as I'm fearing?

[Willh]

No intermix? What does the exhaust smell like? Compression test? Leak down?

[RichUK]

my guess is that it's dodgy radiator cap that's not allowing connection between radiator and expansion tank as radiator pressure/temp. drops.

I don't think so as the cap has proved itself to work, at least once it has allowed fluid back from the res into the rad.

[RichUK]

No intermix? What does the exhaust smell like? Compression test? Leak down?

what's an intermix - or do you mean oil in the coolant, in which case no. The coolant has a film on it but it looks more like chalk dust than oil.

Exhaust smells normal, bad.
No cat so it doesn't have that clean smell.

I don't have the tools to do compression or leak down test, but would either of them show a hair line crack in a head or head gasket?

[Willh]

Possibly. What does the oil look like?

[Willh]

This guy is a bit of an idiot but look at the kit he is using to test for exhaust in coolant.

[RichUK]

Oil looks normal in the sight tube, I haven't looked in the tank itself.

[RichUK]

BTW - If that vid isn't conclusive I could go through giving it a full bleed again (even run the bike with the wheel in the air), and then make a new vid?

[Willh]

I’m having a hard time making judgment on the video because I’m not there. Is it exhaust bubbling out of the radiator or just vibration agitating the coolant. When ever I have blown a head gasket it has been an obvious event, bathed in coolant an no compression. The exhaust in coolant test kit would let you know if you needed to pull the heads.
If there is coolant in the oil than you most definitely have a problem. Look in the tank. Dip and see what the oil looks like.
When I burp I get the wheel easily over a meter in the air,( wheelie), then top up and all is good. Set level in reservoir to slightly higher than minimum on cold engine. Done.

[RichUK]

I’m having a hard time making judgment on the video because I’m not there. Is it exhaust bubbling out of the radiator or just vibration agitating the coolant.

I have watched a vid on Youtube of a CBR600R doing the same and so I'm starting to think that it is normal, as you said.. just the water being agitated, maybe trapped air being moved out, could even be the water boiling as the water system is not being allowed to build pressure.

https://www.youtube.com/watch?v=ICr0C478kbA

If there is coolant in the oil than you most definitely have a problem. Look in the tank. Dip and see what the oil looks like.

Oil in the tank looks fine, still pretty clean too.

When I burp I get the wheel easily over a meter in the air,( wheelie), then top up and all is good. Set level in reservoir to slightly higher than minimum on cold engine. Done.
My skill level is not sufficient to do that I'm afraid.

I decided that I will try to bleed the system one more time but this time I'll first lean the bike left & right as much as I dare, then get the front a little higher and also run the engine to hopefully push out as much as possible.
If the coolant doesn't pull back I'll try swapping back to my old rad cap.

If that doesn't help then I think I'll start a sequence of tests to see what's going on.

1st - Vac & pressure test the whole cooling system to see if I have any small leaks that could be allowing air to be drawn in when the bike is cooling and thus not allow the rad cap to refill the radiator.

2nd - Pressure test each cylinder via the spark plug holes (using a leak down tester) to see if air makes it's way into the coolant. To do this it will mean radiator out so I guess I'll rig up some hoses so I can still fill the engine.

Hopefully one of the above tests will show me what is happening as I really don't want to change either head gasket unless I'm sure it has failed.

[cakeman1]

Don't know if this is of any help but could be a relatively cheap way of checking for exhaust gases in your coolant. We used to use a fancy version of one of these years ago.
https://www.ebay.co.uk/itm/BT-3-BLOCK-C ... 0005.m1851

[RichUK]

Did some more tests and bad news - head gasket gone or head warped.

This is what got me to this conclusion:
I re-bled the system and did good job this time. With the engine running and thermostat open (bike still on ramp) the coolant was calm in the radiator opening, it just got hot and steamed a little - all good.
I put the cap on and let it cool and the reservoir level dropped - I was optimistic.
Today I let the bike idle until the fan kicked in, took note of the reservoir level then left the bike to cool, the level dropped again - really optimistic now.
Took her for a spirited ride and pulled over to inspect, reservoir level higher than before now but as I didn't have the rad shrouds on I could see the whole side of it, and there were bubbles in there - shit..

Left her to cool (desk fan to speed this up), reservoir level didn't drop. Took the rad cap off to see if it had dropped and there was pressure in there, so much that it spat some coolant out.
So I have a small leak, one that only really shows up when the engine is under load, or only leaks enough to make a difference when the engine is hot & loaded.
Either-way I think that is proof positive now.

Bike to be mothballed now, will look at it in October as I should have time for this then.

[cakeman1]

As mentioned before I'd do a block test to confirm the presence of combustion gases in the coolant....only £15 for peace of mind.

[RichUK]

No need to my mind, there is nothing else that could explain why I just can't get it to stay bled, especially when I saw a steady trickle of bubbles in the reservoir.
Afterwards (when cool) the system couldn't pull coolant back in, in fact there was still pressure in there, so much so that it blasted coolant out.

It's a head, or both, it just can't be anything else at this point.

When I return to this problem I want to set it up with coolant test hoses (one for each cylinder) and pressurise each cylinder for a while to see if I can detect which is leaking.

[Motogoon]

Sounds exactly like the symptoms mine had, it was a few years ago now but there's a write up I did somewhere on here about changing the head gaskets, it wasn't too bad of a job to do but I also did my base gaskets at the same time as they were leaking oil and that did add a LOT of extra hours. When I removed it there was no sign of any damage to either head gasket whatsoever but bike new gaskets fixed it.