Yamaha TRX850 Enthusiasts Forum

HI,

i have just seen coolant liquid dripping from my oil gallery bolt, i take it this is a sure sign of a blown head gasket?

Cheers for any help

Mike

Yes I would say so, you could try a `leak fix` additive but it may not have long lasting effects.

Isn't it just dripping of the bolt because it is the lowest point of the engine?
It may be worthwhile to look where it exactly comes from.
If you're "lucky", it is just a damaged hose or leaking waterpump (although that one is on the other side of the engine).

Sadly i can see exactly where its dripping from, its blue (coolant) and dripping from the gallery bolt which is on the cylinder head, left side, the bolt that is used to check oil pressure... Looks like i will have to take the head off again..

Is the coolant dripping when the bolt is tightened, or when you remove the bolt to check the oil?
If the bolt is tightened, how is the coolant escaping?

If coolant is entering the oil galley and mixing with the oil, then it will form an emulsion and not be blue. Can you do a coolant pressure test? or know someone that has the correct tools for a pressure test?


Some generic information, http://www.benplace.com/pressure_test.htm

@dicky @rod It is clear blue, drips defo from the gallery bolt, can see it happening when the engine runs. Rode her the day before yesterday and nothing to see, rode her yesterday and could see it dripping, maybe there hasnt been enough time for it to emulsify with the oil?? The really funny thing is that the bolt is tight as a gnats arse...havent opened it yet, was waiting for advice.

the bolt is tight as a gnats arse

Then the coolant is coming from somewhere else and just dripping of the outside of the bolt.
If it was leaking internally it would be mayonnaise within seconds, and you would see an oily mess leaking somewhere.
Check the coolant line to the carbies, the thermostat housing, the temp sender, anything above the level of the bolt, both sides of the engine.
I'd bet Rod.s money that it's leaking somewhere else and simply finding the bolt as the lowest point, that's why you see it there.

hoyhoy9 wrote:@dicky @rod It is clear blue, drips defo from the gallery bolt, can see it happening when the engine runs. Rode her the day before yesterday and nothing to see, rode her yesterday and could see it dripping, maybe there hasnt been enough time for it to emulsify with the oil?? The really funny thing is that the bolt is tight as a gnats arse...havent opened it yet, was waiting for advice.

Is it this bolt? If so there may be a crack in the casting….a pressure test will tell you

Thats the one. I will check visually later, will try and do a pressure check somewhere.... Thing is, also she runs a bit rough (carbs need synching) at about 4000.-4500 revs she starts to stutter and lose power, sont know if related at all to thus problem

I reckon it could be leaking at the coolant pipe that goes into the top of the head, then seeping across the cam cover and down onto the bolt.
This may cause the plug leads to short out.
Could also be the thermostat housing dripping onto the cam cover.
I have repaired both of these recently, they are slow and hard to spot, but the leak escalates quickly.
Good luck.

Hi Guys, thanks for all the help, sorry for all the bother, if i hadnt been so scared because of the gallery bolt i would have looked more closely myself without involving the forum...

It indeed seems to be the thermostat housing, definitely not coming from the gallery bolt but above and running across the valve cover and dripping off the gallery bolt. I can see it dripping from the bottom of the thermostat housing, 99.99% thats the culprit.

Thanks for all the great and really fast responses. Brilliant stuff.

Mike

Allright then.
Now, how are your headers so blue?

They are not mine...

Is it worth while trying a cooler sealant additive or is it just a waste ofe time or even detrimental to the cooling system ( clogging etc..)?