I'm having trouble with my coolant reservoir on my 2004 Mustang. Everytime I put coolant into the reservoir it depletes within a matter of two weeks. I know there is a leak somewhere in the lines, but my lack of technical knowledge limits my ability to fix this problem. I would like to do this myself, instead of a mechanic, so I can learn how my car works. Can anyone help?

Thanks,
Josh

 

Josh,
Have you over heated?

It is possible you have air in the system. To properly fill you need to remove the filler plug on the cross over tube. Before doing that fill the expansion tank to the full line. replace the cap. Now remove the cross over plug. I like to put a 2 quart funnel into the hole and turn it clockwise. It will tighten and form a seal. add coolant/water into the funnel and fill it half way. Start the engine bumping the throttle a few hundred rpm up and down. You will see bubbles escaping and the level will drop in the funnel. Keep the level up in the funnel so air doesnt go back into the engine. Once all the bubbles have stopped replace the plug. Do not tighten too much because the engine is warm. When it cools off it will take a lot of effort to remove it next time as it will be over tight.

After filling the system go to an autoparts store that will rent a pressure tester like autozone. pressurize the system as instructed. leave it over night. it should not loose pressure. If it does look for the leak.

Another thing to be aware of if you have overheated. You may have a bad thermostat.

 

It has overheated in the past. During that time we replaced the thermostat thinking that was the problem but it still kept overheating. We finally remembered to check the reservoir and found that it was bone dry. About two to three weeks later it was extremely low, and we filled it up again. Lately I've been having mechanics check the fluids when I change my oil and they fill it up every time. I'm getting tired of the problem and want to try to fix it myself. I'll give your idea shot and see what happens. Thanks!

 

Your leak may be a blown head gasket. That would explain the coolant loss and the overheating. Hot combustion gases getting into the coolant quickly brings it to overheat stage. Get the car warm and smell the exhaust coming out of the pipe. Does it smell sweet like anti-freeze does? If so, then you have a blown head gasket. Hope I am wrong.

 

Get a leak testing kit. They come with a UV colorant you add to your reservoir and a UV lamp. Run it for a few days and check with the light and you should be able to spot the leak. Over heating can be caused by bad thermostat, bad water pump, plugged radiator or bad cooling fan. Anyone of those can be your culprit.