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Pistons shiny sparkplugs dirty

I have a four cylinder and when I changed the spark plugs two of the pistons were shiny and clean but all the spark plugs looked the same. (tan color)
Can a gasket leak make the pistons steam cleaned and the spark plugs look normal?

Yes. What kind of car and is it losing engine coolant?


It would be odd for all 4 cylinders to be affected the same way. You might try a compression test.

2000 Suzuki Esteem 156 000 Miles
It does not seem to be loosing much coolant at all.
The two pistons either end of the engine are shiny and clean and have that new steam cleaned by coolant leaking through the head gasket look to them and the two middle cylinders have the healthy looking carbon layer on them that makes them look the typical black color.
This is the bit I don’t get. How does the steam not clean the spark plugs on the two shiny cylinders? Maybe it is shrouded by the head and does not get steam cleaned. I was wondering if it was possibe for the fuel to do a similar thing.

I guess whatever the answer is, I need to get my hands on a compression tester soon and then I will have a better idea of what is going on.

The tan color on the spark plugs is normal. This is caused by the additives in the gasoline.


This is why it is surprising.
I would have thought that a shiny piston would have a shiny spark plug.
A normal piston would have a normal spark plug.
In my mind at least, this is most unusual.

How were the pistons examined? If your description is accurate, I’d suggest a cylinder leakdown test, but you can’t see much looking through the sparkplug holes (unless you have a borescope) and I’d be reluctant to make any assumptions by doing so. The plugs all being of healthy color and condition suggests to me that your perception of the inside of the cylinders is perhaps not accurate. I’d bet that if you were to pull the head (and I am NOT recommending doing so) you’d find the pistons to be a lot more consistant than you think.

I looked down the spark plug hole with a flashlight.

I could try to take pictures but it would be hard to get light and to focus down a spark plug hole.

I am assuming it is a straight line of sight to the piston and all I see down the sparkplug hole is the piston top. I assume that I can not see the cylinder wall which would almost always be shiny regardless of steam cleaning.

So it sounds like it is very common for steam to clean the plug as well as the cylinder on almost all other cars that have had the head gasket blow. It sounds like everyone has had the plugs go shiny and clean with a head gasket leak.

Did you turn over the engine to get each piston to the top? If you just pulled all 4 plugs and looked, then each piston would be in a different position, the ones further down their stroke would look darker.

I’d be inclined to consider the condition of the sparkplugs and operating characteristics to be far more indicative of the engine’s condition than anything you can see through the sprakplug holes.

If it’s running good and the plugs look good and even, and you have no excessive fluid loss issues, than you’ve nothing to be worried about.

I commend you for your conscientiousness. With time, you’ll learn to sort out what’s important and what’s normal.