Yesterday, I was on a truck with my 4G VTEC. After about 15 laps, the temperature increased from middle to maximum (in one lap, so the increase was quick). I slowed immedately, turned heating to max and cruised, so the temp decreased back to normal in about 2 minutes.

After I stopped, there was water near the water tank, on and under the battery etc., like it overflowed.

Some facts:
1) It was relatively cold, about 10C (50F), do I don't understand how could I get so hot.
2) Heating was set to a half all the time from the start.
3) Both the fans on the radiator are OK (tested after the run).
4) When I was downshifting to 2nd gear in turns, I sometimes saw "something white", like a smoke in my mirrors. I assumed it is my tires and didn't attend to it. Now I realize that it could be a white smoke from my muffler.
5) On my way home, the temp stayed in the middle all the time, and I tried to drive hard.
6) I found no other water leaks

When I got home, I made little research and pics:

I removed the plugs and #1 is more white than the other 3 (#1 is on the left side):


The plug #1 has also some deposits on it's one side:





At this moment, I realized that about 500miles ago, I checked all the plugs and #1 had some strange deposits on it's side, it was relatively big (about 4x4x4mm) and very strong, looked almost like a stone. I removed it with a screwdriver and returned back. The plugs had about 5000miles on it at that moment. Now I realize that the deposits look the same, only now it is a lot smaller (it has only 500miles from the "cleaning").

I found no oil in water or vice versa, but I found some strange chips on the radiator cover:






It looks like some deposits too, anyway, I looked on the cover the day before the truck and there was nothing like this.

What can this be? Maybe a bad head gasket? If I will replace the gasket, should I regrind the head to set it in level - note that the temp. increased to max on the indicator, so can the head be warped?

Thank you for you valuable info,
Petr.

 

First off, great pics to try and help sort this out, answers a lot of questions that you didn't address with words.

The deposits on the #1 spark plug looks more like a fuel impurity caused deposit more than water, so I'm not sure that the water temp shooting up and the spark plugs are related. It doesn't make good sense on why it would only be on one spark plug if it was fuel related though, unless you have a single injector that is slightly clogged, which is entirely possible.

As for the deposits in the radiator cap, it appears you're over due for a strong cooling system flush and fill, because to me, it looks like some calcium or lime deposits, which after a while can form hard pieces that can block your cooling system ports pretty hard, and shoot up in temp as you described. After you get the whole system flushed DO NOT USE TAP WATER WHEN CUTTING YOUR ANTI-FREEZE 50/50, USE DISTILLED WATER. Distilled water won't have the calcium or lime, or any impurities to bring your problem back. Some places have a water works that does a good enough job that you can get away with using tap water, your locality is obviously not one of them.

As for the possible warped head, watch for fluid consumption, and pull a compression test.

 

So, today I made the "bubble test" and I have videos for you to discuss it.

When I started the car, there were no bubbles, but the coolant level was still rising, I mean it was still going up and overflowing, all the time. It looked like the engine is going to empty all the coolant:
http://www.volny.cz/veitel/prelude/o...t/overflow.mpg (1.2MB).

Once the thermostat opened, the bubbles started to go out of the radiator, even at idle, even when revving:
http://www.volny.cz/veitel/prelude/o...t/bubbles1.mpg (1.5MB).

So, it looks like a blown head gasket now, right?

 

Yeah, it would seem so.

 

Yep looks like a head gasket gone bad to me.