green tint/coolant on spark plug?
 

Hi All,

I have always had a misfire when i first got the car about 6-7 months ago. I changed the plugs in December, but it still misfires a bit - so I am thinking something might be up. I checked the plugs, there is a bit of oil on them due to a valve cover gasket leak, but I also notice a little green tint on the electrode and threaded part of the spark plugs. Is the green tint due to coolant passing through the cylinders or is it something I shouldnt be concerned about? I am not overheating, no coolant in oil, no smoking, but i have been losing some coolant from the expansion pack by the radiator (but noticed the cap wasnt on tightly) - i really hate to think it is a blown head gasket!! I will have to do a compression test to confirm.. any ideas? I also added mystery oil to gas tank and crank case, as well as seafoam to gas tank and intake manifold.

I'm thinking it might be a head gasket, it might just be a small enough leak that there's no visible smoke

the coolant level goes up and down.. not sure why? maybe theres still air in the system? i just hope my car is running a little lean, causing the plugs to turn green.. maybe my cat is bad?

If is bad gasket oil and coolant are mixing, sometimes they leak to one and sometimes to other side.
If your coolant goes to oil then coolant level goes down, but if your oil goes to coolant then coolant level goes up. They circulate both way.

Check your oil cap it has to have something with white or green color on it (inside). That is really good sign that your engine do mixing oil and coolant

i will check again later, but i checked everything and did not see the signs of a head gasket leak.. still need to go to autozone and pick up a compression tester..

But before you panic if you see white residue on your oil cap, keep in mind that condensation does collect inside the block and it will show on the cap. This will be the case, especially, when the car is driven short distances. If however, there is still white, or milky, residue after a long drive, you might be leaking coolant.

nope not white residue last time i checked the oil cap which was on saturday.. i mean i dont have any symptoms of a head gasket leak other than the plugs having a green tint on them.. i really really hope its nothing serious..i do want to replace my cat and possibly my o2 sensor..might calm the rough idle a little..

I actually have green tint on one spark plug as well. I fully rebuilt the motor with all new everything, and there is green tint on cyl #4 plug. Incidentally, that cylinder is 5psi lower than first three. The car is a bit lean, so i wonder if the discoloration has something to do with that.

I've seen heads get "porous" spots in the casting. They suck coolant in during the intake stroke but don't really leak and often don't push combustion gasses into the water...

Dave

does this mean i dont have a head gasket leak?