bad head gasket, loosing coolant. | GTAMotorcycle.com

bad head gasket, loosing coolant.

M

Motof4st

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anyone have head gasket issue ? did it cost a lot to replace and diagnose ?
i'm loosing coolant through the reservoir and i'm hoping it could just be the rad cap is no longer holding pressure.
the oil is clean and no signs of sludge on top in the sight glass and i haven't seen white exhaust.
noticed engine overheat on last ride and found coolant low in rad after it cooled enough, with no coolant in reservoir.
topped it up and filled reservoir to proper level and started the engine. i did find the coolant being pushed into reservoir
a few minutes after start up.
Q; would an air lock situation cause this ?
 
Is there any sign of where the coolant is going? Any white steam coming out the exhaust, or does it smell sweet? Two easy signs for diagnosing head gasket issues if the engine is burning it.

No oil in the coolant (and vice versa) is good but doesn't necessarilly rule out the head gasket, it just means that it didn't let go anywhere that has allowed oil to get into the water jackets, although on most bikes there are not oil passages that far up anyways.

If there's no explanation where the coolant is going, start by pulling spark plugs - a cylinder that with a head gasket leak will have the plug nicely steam cleaned (and the piston head typically will be shiny as well if you have you can peek in while it's at TDC) so it's an indicator.
 
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Make, model, year, mileage, please.

Replacing the radiator cap is a cheap and easy first step. It isn't worth diagnosing, just replace it. There is a fair chance that if you take the old radiator cap to Canadian Tire or NAPA, you can match it up to a generic automotive one. Make sure the pressure rating matches (or is higher than the original).

Air locks within the cooling system can cause coolant to be pumped out ... but the design of most cooling systems avoids this, and as the air slowly works itself out, it should subside over time. If your cooling system has coolant rerouted through something non-OEM, that can introduce air locks not present in the original design. (I have a situation like that)
 
Also, typically, replacing a head gasket is a moderately big job. Typically, the engine has to come out, and that means you first have to disconnect and remove EVERYthing connected to the engine. The tensioner for the timing chain comes out, then the camshafts come out, then the head comes off. Then the surfaces have to be carefully cleaned to remove gasket debris without removing metal (*don't* use harsh abrasives). The block and head have to be checked for warpage and this may lead to either one or both requiring machine work ... failing to do this WILL result in the replacement gasket leaking again.

http://www.gtamotorcycle.com/vbforum/showthread.php?178050-FZR400-winter-overhaul/page4 start at post 69; this gives you an idea of the scope of the project (this covers reassembly only). If your cylinder head is not warped, the valves don't need to come out. If the cylinder head is warped and needs machining ... they do.
 
I am gathering from doing a little bit of sleuthing that this involves a MV Agusta F4, unknown year and mileage. Oh fun.
 
anyone have head gasket issue ? did it cost a lot to replace and diagnose ?
i'm loosing coolant through the reservoir and i'm hoping it could just be the rad cap is no longer holding pressure.
the oil is clean and no signs of sludge on top in the sight glass and i haven't seen white exhaust.
noticed engine overheat on last ride and found coolant low in rad after it cooled enough, with no coolant in reservoir.
topped it up and filled reservoir to proper level and started the engine. i did find the coolant being pushed into reservoir
a few minutes after start up.
Q; would an air lock situation cause this ?


did you do any recent work to the bike?

you might have your over flow tube that connects to the revisor mixed up with the re-circ line to the engine. the revisor tube must be on the highest tube on the rad.
 
Brian you are a natural sherlock Holmes , sir.
you are correct, 2011 F4 and it has 33000 kilometres on odometer and i did have work done on it last summer, BUT not by myself.....you should know where it was worked on if you dug that deep.
i've only ridden it four times this season so far.
i performed a pressure test, it held pressure at rated 110 to 120 kilo pascals which is around 16 psi.
topped it up first though and then ran the engine until it warmed up. coolant level rose inside the reservoir, but did not flow out the waste tube. so far good news.
went for a ride and found that the coolant levelled off, so my guess is that the system was not properly filled in the first place as i topped it up by about almost half litre.
it's still full after a couple more rides, but as with everything else, i'm keeping an eye on it.
i checked your thread on your FZR400, very nice... yes it looks very involved.
 
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