Just replaced all the spark plugs, cap, rotor and all the cables. Dealer quoted me $750.00 plus parts for the job so I just bought the parts and did it myself. Anyway, I noticed that all the spark plugs have oil/brown water looking substance on the threads. Does that mean there is oil in all of the cylinders? Is this a head gasket issue? Please chime in if you know about this. I will post pictures of the old spark plugs later. Thanks
When you say "on the threads", do you literally mean that, or are you saying the oil/water is on the ceramic business end?
If it's just on the threads and the ceramic is a nice pale brown, then you may just have some leaky plug tubes that let some oil/water in; the threads can pick up the oil/water when you pull them.
But if you have oil/water on the bottom ceramic part, I'd think you want to check for bad HG.
Was there the same stuff on the plugs when you took them out the first time ? If there was it may just be anti seize compound, not a bad idea with an aluminum head.
If they all looked fairly uniform, you're fine. It's normal to have deposits that range from black to brown to light brown depending on a bunch of factors. If you actually had water on the plug it was likely from either recent water travel (rain, etc) or from someone actually washing the engine with a sprayer.
If there's water in the cylinder environment from a HG, that plug would be completely and perfectly clean while the others would have normal deposits. From your description everything sounds as normal as can be.
The biggest thing is if they're all approximately similar looking - by FAR the most information you can get from looking at spark plugs. One plug clean, much blacker than the others, much lighter, etc would indicate a closer look is needed.
It may be that the two that look like dark threads were slightly loose and not sealing well. This would allow combustion fluids/gasses to creep up the threads . Just what i have seen over the years with loose spark plugs. But otherwise the spark business end look to be in the normal range.later robbie
Thanks every one. I had never seen this scenario before. Usually things like this meant serious problem to me, in general, ofcourse for other vehicles I have driven. Thanks for clearing this out.
They are, but I'm attributing it to the unnatural effect of a flash. Slightly light is generally OK, however, vs the darker shades. Might be long term use of inferior gas.
Sorry, confusing. The effect of a flash on a camera to lighten things in that shade. Darker deposits are often associated with oil consumption, excess cylinder heat, etc. I think there's an excellent commentary in the LandCruiser Factory Service Manual that's a good primer. Otherwise a search on the net will yield some good photo comparisons.
