coolant in spark plug well

Hi all,

already mentioned on another thread but here’s the situation:

I have coolant dropping from the sparkplug drain hole on the left of the engine block…

oil looks fine as well as coolant so no sign of contamination

the valve cover gasket looks old and sometimes damp but as far as i know only oil could leak from there, not coolant.

two days ago the bike overheated a bit as i was stuck in the traffic for quite a few times and yesterday inside the 1st spark plug on the left, exactly where the valve cover gasket is I found few drops of a “milky” substance , so it means oil is mixin with coolant somewhere, but as they both look fine they probably just mix up there somehow…

oh, the bike runs perfect

Now searching the web I found 2 possible solutions when coolant can leak from the valve cover:

  1. Freeze plug failure that allows coolant all the way up and then leak from the worn gasket ( some gsxr forum)

  2. Intake manifold leak that can allow coolant to the spark plug well… ( some cars forum)

Any of you ever heard of these happening?

Do you have any leaks from the hoses that could have dripped it into there ?

i used to have a small leak from the thermostat gasket which is right above the head but i fixed it and it’s fine now…

then, right next to the carbs manifolds there are 2 pipes (1 on each side) that bring the coolant from the engine back to the thermostat and to the radiator

i think the orings inside (between the engine and the pipes) are worn as i can see some coolant residue, but i’m not sure if these oring could cause an internal leak…

probably the only solution is to open the valve cover and see what’s going on…

If its the head gasket … Valve cover off aint far enough … You will need to go deeper than that . drop some coolant out the water pump drain see if its tainted . Drain your oil look for milk . It usually settles at the bottom of the sump if left over night so usually comes out the drain plug first . Catch the first few glugs in a seperate container so you can inspect it . Get a compression test done …Also … What bike is it ?

I frequently get rain water in the left plug hole. It’s the same side as the kickstand so it runs from right to left across the top of the cam cover when the bike gets parked. Not a Triumph is it? :hehe:

If you run the bike up temp can you see where its actually coming from to get to the spark plug hole ?

Doesn’t sound like an internal (head gasket, for instance) leaking coolant into oil or v.v. to me. That usually tends to a milky emulsion, so sounds like an external coolant leak.

I’d make sure any coolant pipes, metal and “rubber”, are sound and properly sealed at each end then check the inlet manifold joint to head before I went into serious spannering.

I’m pretty sure is no rain water,

i’ve been checking everytime i take the bike and i always find drops in the left ignition coil and the inside of the sparkplug well is wet, so it looks is coming from the valve cover gasket

the thing is that coolant shouldn’t get upthere!!!

Oldguy: i read in another forum ( it was car related) that a defective inlet manifold can allow coolant all the way to the sparkplug well, but first of all how is it possible?

I thought no coolant should be around it and even if, how does it make its way to the spark plug??

You want to get it all dry an clean then run it up to temp and sit and watch it …

I try to check when the bike is hot, however i can’t see exactly what’s going on inside due to the ignition coil,

what happen if, when hot and leaking, i turn off the engine, take the ignition coil off and turn on again to see inside???

the bike will run with 3 cylinders, is it dangerous if done for few seconds?

I would be completely eliminating that the water aint coming from a drip somewhere before I worried much about whats happening in the plug hole . Clean and dry and start testing from an as it should be position . If I fills with.water while you sat and watched it …it will give you a clue to what step is next … the most simple rudimentary sit and watch diagnostic is tried and tested as fool proof … Almost :wink:

the head is dry, but still the well is wet…

can i try as i described above or is it dangerous?

that would be the only way to look inside the well while the engine runs…

You dont need to see inside the well while it is running if you have made it clean and dry . Then once its clean an dry put it together like it should be start it up an watch . Get it up to temp watch for drips if you see none … Pull the cap off an see if it wet in the hole again .

already done,

this morning before going to work i checked the ignition coil and it was dry, arrived at work (about 7 8 miles) and there you go:

drops from the drain hole and ignition coil wet…

Once more from the top . Cap/ coil off, plug hole spotless and dry ,cap spotless and dry ,put it back.together,start it up sit and watch . Then once its been up to temp fans kicking in with you sitting an watching . Then shut it down and inspect.

sorry num num i don’t get it, what’s the difference between what you and I said?

when cold the hole and the coil is dry, when hot is wet…

the only thing that can leak inside there is the valve gasket, isn’ it?

All you have done so.far is tell me your spark plug hole gets wet when you ride your bike … Which tells nothing . I want you.stationary unaffected by wind puddles angry wildebeast or whatever . And test it under a more laboratory condition than rush hour traffic. With everything spotless before you start . Does that not make sense to you ?

ok got it,

i will try later on and let see if i notice something different…

cant wait.

Oldguy: i read in another forum ( it was car related) that a defective inlet manifold can allow coolant all the way to the sparkplug well, but first of all how is it possible?

I thought no coolant should be around it and even if, how does it make its way to the spark plug??

Almost all cars and many bikes have water (coolant) heated manifolds these days. The most common practice for getting the coolant to the manifold is to have driillings from the cylinder head to take the coolant to the manifold and back. The drillings are commonly sealed only by the gasket between the manifold and the cylinder head.

Given the coolant is pressurised to about 1.2 bar, a small weep on the manifold to gasket joint will leak coolant, usually externally.

The old trick (I only know old tricks) for finding coolant leaks was to shove a bottle full of bright red food dye (colour is optional!) into the cooling system, run the bike and look for the stains.

Warning. Food dye can be a reet bugger to get off the aluminium.