Diagnose Blown Head Gasket
#1
#8
Took the car to my mechanic of 30+ years and he tells me the head gasket is not blown. He thinks its just a sensor. He did say the coolant was a bit low in the bottle and told me to add some.
I still want to know why its low in the first place. He put it up on the lift and checked it out thoroughly. No signs of anything leaking anywhere..
I still want to know why its low in the first place. He put it up on the lift and checked it out thoroughly. No signs of anything leaking anywhere..
#11
We had a problem with our S70 loosing coolant. Adding about a cup or two per week (about 100 miles). The tale sign for it was that the low light was on when the car was started first thing in the morning, when it was cold. Then when it was driven the low light went out. The head gasket was bad.
You are not suppose to open the coolant tank when the car is warm, only when cold. So check it when it's cold and if it needs coolant fill it up then.
I took the car for a drive and 5 minutes into the drive I pulled over, popped the hood and the tank had more coolant in it, drove 5 more miles (freeway driving) checked again and it was forcing itself out of the tank cap. The thing that blew me away was how fast the stuff dried, it was almost immediate. I guess that's because of it's temperature.
I'm not saying that you have a head gasket problem. Like ES6T explained, you likely have a small leak that needs to be pressure tested to find. You may also be able to add some iron dye in the system and get a black light to find it. Loosing coolant all the sudden is not normal. As for the level in the tank, it should stay steady all day long.
Head gaskets just don't go bad, there is always a cause. 1. Overheating; 2. A previous bad install job. Don't know of any others. I will tell you this, driving around with a leak is engine roulette.
You are not suppose to open the coolant tank when the car is warm, only when cold. So check it when it's cold and if it needs coolant fill it up then.
I took the car for a drive and 5 minutes into the drive I pulled over, popped the hood and the tank had more coolant in it, drove 5 more miles (freeway driving) checked again and it was forcing itself out of the tank cap. The thing that blew me away was how fast the stuff dried, it was almost immediate. I guess that's because of it's temperature.
I'm not saying that you have a head gasket problem. Like ES6T explained, you likely have a small leak that needs to be pressure tested to find. You may also be able to add some iron dye in the system and get a black light to find it. Loosing coolant all the sudden is not normal. As for the level in the tank, it should stay steady all day long.
Head gaskets just don't go bad, there is always a cause. 1. Overheating; 2. A previous bad install job. Don't know of any others. I will tell you this, driving around with a leak is engine roulette.
#13
#14
if you do anyway, don't put the cap back on until the system is cold, radiators are made to withstand pressure, not vacuum. when the coolant cools, it shrinks and that vacuum it creates can damage certain components.
#15
You can put the cap on, nothing will happen.
The vacuum that would be created is too small to do anything.
Also, the radiator can handle vacuum just fine. If it can handle pressure, it can handle negative pressure.
We often use a tool to fill the cooling system faster. It attaches to the reservoir and shop air. It then creates a vacuum and that vacuum is used to pull coolant into the system. This pulls about 21 psi of vacuum. The vacuum that could theoretically be created by putting the cap back on hot wouldn't be close to that.
The vacuum that would be created is too small to do anything.
Also, the radiator can handle vacuum just fine. If it can handle pressure, it can handle negative pressure.
We often use a tool to fill the cooling system faster. It attaches to the reservoir and shop air. It then creates a vacuum and that vacuum is used to pull coolant into the system. This pulls about 21 psi of vacuum. The vacuum that could theoretically be created by putting the cap back on hot wouldn't be close to that.
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shai_kino
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08-20-2014 06:45 AM