Leaking head gasket

2001 NISSAN XTERRA
181,000 MILES • 4WD • AUTOMATIC
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JCORDNER
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My head gasket was leaking, car was having white exhaust, and a rough engine and leaking coolant.

Okay, so I had a mechanic put in the good stuff, the head gasket sealant for the head gasket. I made sure it was the right sealant for the Nissan and the best I could find. This was three weeks ago. Immediately the leaks stopped, (car was leaking coolant not oil) no white exhaust, no coolant leaking.

Radiator is still full to the top with the coolant that was put in there three weeks ago.

(Yes, the mechanic gave it an oil change and flushed the radiator before adding the sealant.)

I only ran it to work and back about twenty minutes, with the heater on full, for circulation, ran great for two days. Then it started overheating after driving for twenty minutes.

After about twenty minutes of driving, When I stop at a red light, or slow down, or hit traffic, the temperature goes up to just below the danger line or the last quarter of the inside temperature gauge.

Once the car starts to move again, the temperature will start to slowly go back down again.

Up to twenty minutes the temperature holds perfectly at the half way mark with freeway driving. And I have to say, other than the over heating, the car has never run better. Noises from the heater are gone, engine is quieter, things like that. Transmission is strong, radiator is not leaking.

The mechanic took another look at it, but could not find anything wrong. I do not think he looked that hard.

I have heard that sometimes if the thermostat is not removed while adding the sealant to the car, the thermostat could get stuck.

So I started to think, if the thermostat is stuck maybe when the car really starts to heat up at about twenty minutes, then that might be what is causing it over heat?

Is it worth replacing the thermostat or is it off to the salvage yard?

Oh, I should also mention that before the head gasket broke down the thermostat had a little leak. It was not bad just something I knew I had to get fixed eventually. The coolant only needed to be topped off every three hundred miles or so and then only quarter of a quart.
May 26, 2018 at 3:44 PM
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ASEMASTER6371
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Good evening.

First, there is no such sealant for a leaking head gasket. The only repair is to replace the failed gasket. All the sealants do is clog up the radiator cores and the heater core with the sealant.

The gasket has started to leak again and it is allowing air into the cooling system. This air is causing the temperature to go up and down as you see.

The best course of action is to replace the head gasket. If you continue to run it as is, you can do damage to the motor.

Are you going to try this repair yourself?

Roy
May 26, 2018 at 5:17 PM
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JCORDNER
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Thank you for answering my question. I was hopeful there was another answer. But thank you for your time.
May 26, 2018 at 5:50 PM
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ASEMASTER6371
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You are welcome. Sorry for the bad news.

Roy
May 26, 2018 at 5:52 PM