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Matt, Mechanic
Category: Car
Satisfied Customers: 100
Experience:  10yrs auto, diesel and small engine mechanics training and work. Diploma in engine repair.
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The reserve tank on your cooling system damage the head gaskets

Customer Question

Can overfilling the reserve tank on your cooling system damage the head gaskets?
Submitted: 6 years ago.
Category: Car
Expert:  Matt replied 6 years ago.
<p>Over filling the reserve coolant tank should not damage your head gaskets. The reserve tank is there in case the radiator becomes low on coolant as a supply system, and to catch any coolant that the radiator spills out due to overheating.</p><p> </p>
Customer: replied 6 years ago.
Why would a mechanic deliberately overfill the reserve coolant tank - It caused alot of problems with my car - it is not driveable. The computer system went nuts and shut the car down.
Expert:  Matt replied 6 years ago.
<p>A mechanic? Can you help a little with your question by telling more about exactly what happened just before the car started acting up? Was it in a garage for work? Or sitting on the road where someone could tamper with it as your original question states was done?</p><p> </p><p>I will help you as much as possible with this. It would not be standard practice for a mechanic to overfill anything on your car. Even if there was an overfill on your coolant reserve tank, this should not have affected the computer's operation, nor should this have blown any head gaskets.</p>
Customer: replied 6 years ago.
Last summer, this particular mechanic told me that my head gaskets were blown and it would cost thousands of dollars to fix. After talking with several people, whom all stated that there would be white smoke billowing out of my exhaust if that were true. Recently I took my car to a mechanic who is a friend of mine (but is 60 miles away). And he checked my car top to bottom, told me my head gaskets were fine. He flushed the cooling system and put in new DEX Cool. I had my oil changed, the whole bit. Within a week or so, my car was in a minor accident, but had a major bill. The car was first brought to the mechanic from last summer because it was not driveable. My insurance co. told me to have all the work done at the body shop next door, which I did. I picked up my car on Wednesday. I live a few miles from where it was fixed. I barely made it home - the digit dash kept blinking message - car hot a/c shutting down, oil needs to be replaced, car overheating shutting down (these are just a few). We opened the hood and coolant was spewing out. The next day when the engine was totally cool. We opened the coolant reserve cap and it was so full some fluid spilled out immediately. It was full to the top of the cap. I can't for the life of me understand what they did to my car.
Expert:  Matt replied 6 years ago.
<p>Addressing the first part (blown head gaskets), the car won't always smoke if a gasket is blown. You may find oil getting into your coolant system which would leave a sludge film in it, or you could find coolant in your oil which would cause the oil level to appear higher on the dipstick and the oil would be shiny and thin like water.</p><p> </p><p>When the car was taken to your friend, did you notice if he overfilled the coolant reserve tank at that time?</p><p> </p><p>Was the accident in the front of the car? This could have caused damage to the coolant system. Even minor fender benders in the nose area can bend coolant lines or poke holes in the fins of the radiator. If the repair shop noticed coolant loss, they may have overfilled the reserve tank themselves. Without being there to check it each time, it is hard to say who did it and when it was done.</p><p>The blinking messages you are getting could be coming from damage that was done in the wreck. There could be physical damage to the coolant system or there could be damage done to a sensor somewhere. </p><p>The overflow of coolant in the reserve tank could be several things including one of the people who has worked on your car filling it that full or cooling system damage that is back-flowing pressure in the system and pushing coolant from the radiator into the reserve tank. One thing to note is that a blown head gasket can create pressure from the cylinder area into the coolant which would have this affect.</p>
Customer: replied 6 years ago.
My friend has been a mechanic for 30 years. He showed me the reserve after the car was running for an hour and a half. He did not overfill the tank. The damage from the accident was mainly to the right front wheel and axle. There is no coolant in my oil. As I said the dash messages appeared after the car was fixed not before. Also, the mechanic said I had blown headgaskets last summer. I have had no problems with the car up until the accident a couple of weeks ago.
Expert:  Matt replied 6 years ago.
<p>I would return to the shop that did the repairs and ask what all they did to your car. Also, if the accident was the other person's fault, you want to make sure this is still fixed under their insurance. </p><p>Since original question was about the head gaskets and the coolant, that is why I have addressed that each time. Over filling the reserve tank will not blow your head gasket.</p><p> </p><p>As for the repair shop and what they may have done to your car, that is hard to say without being there. If the only issue was the computer, the impact of the wreck could have damaged it. Some computers are mounted on the firewall of the right front fender well.</p>
Expert:  Matt replied 6 years ago.
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