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Possible Head Gasket Woes Continued... White marks on plugs

2026 Views 5 Replies 4 Participants Last post by  iametarq
Figure I'd start a new post on this subject since I couldn't find anything in this forum about it, and someone else in the future might have a similar problem.

Anyhow... as some of you know, my car is overheating. My mechanic did a pressure test today on the coolant tank and said there are no leaks. So where is my coolant going?

He checked out the spark plugs and said I probably had a blown head gasket. The plugs are only three weeks old and already have white markings on them as if they were burnt by a chemical. My mechanic said this is coolant getting into the cylinders. Is this true?

Is this enough evidence to know for sure that a head gasket is the problem?

Should I still proceed with a cylinder pressure test?

Is there any other explanation for the white marks on the plugs?

Cad tech suggested I do a block test? Any thoughts?

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White residue is usually coolant. A block test can't hurt and is pretty cheap compared to a head gasket job so you want to be absolutely sure, though I hate to say it doesn't sound good.
What would a block test determine; if I have a head gasket problem or a crack in the block? Any positive outcomes to this? LOL.
So where is my coolant going?
Your coolant is going into the combustion chamber and being burned with the fuel, hence, the white residue it leaves on your plugs. The coolant then exits through the exhaust system. It may or may not ruin one or more of your o2 sensors, so if you get a check engine, its more than likely because of this. Your oil is probably milky from being mixed with coolant as well. I wouldn't drive the car, you risk warping a head or cracking one, or doing some other serious engine damage. I don't think your block is cracked, yet.
I'm still wondering if I should be worried at all.

I am hoping the white on my plugs was due to their extreme age and extreme long distance driving it has been doing ever since I bought it. There is barely any white on the plugs. I have never had my temp guage go past 12 o'clock, except in the mountains of colorado while driving up a mountain, when I was already at about 6,000ft above sea level.
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