Posts Tagged ‘condensation’


Why Is My AC Irregular?


Recently, my AC has started acting up.  When I first start the car, it will blow cold air, but after about 15 minutes, it blows hot air.  Another 15 minutes and it blows cold air again and keeps cycling like that.  What is happening and how do I fix it?

- Horace F., AZ


The symptoms you are describing make me think that your AC unit is actually freezing itself.  As the compressor starts working, it gets colder and colder until any moisture on the unit freezes.  After seizing up, your air runs hot again until the unit thaws, after which the compressor freezes itself again.

The root cause of this problem could be any number of things, so here are a couple things you should try.

1.  If the humidity in the air is high enough, condensation might form in and on the compressor when it starts.  Try running the engine for 15-20 minutes before firing up the AC.  This should equalize the temperature under the hood and minimize condensation.

2.  Your system may be plugged.  Try removing and refilling all of the coolant.  This may free things up.

There is also a remote possibility that your compressor is actually faulty.  Unfortunately, it may need to be replaced if the above methods don’t solve the problem.

- Ken the Car Guy


How Often Should I Change My Oil?


I’ve been told I should change my oil every 7,000 miles, but I only make short trips so I never drive more than a couple thousand miles a year.  How often do you think I should get my oil changed?

- Dan K., CA


Most engine manuals recommend changing the oil after a certain number of miles because oil inevitably gets dirty after use.  Carbon buildup, humidity and temperature changes can all affect the viscosity of oil.

If your engine only sees occasional use, the oil can still loose it’s functionality due to humidity and temperature changes which cause condensation to bleed water into the oil system.  If you don’t drive the suggested number of miles, a good practice is to get an oil change once a year, especially if your car is kept outside and sees regular changes in temperature.  This will keep your oil system healthy and prevent problems down the road.

- Ken the Car Guy


What Should I Do Before Starting An Unused Car?


I just bought a car that has been garaged for several years and want to make sure I don’t damage anything when I try to start it for the first time.  What should I do to improve the chances of a clean start?

- Derek C., FL


Your first step should be to replace all the fluids in the car.  Over time, condensation in the gas tank can lead to water buildup which can damage the engine.  After draining and replacing the gas, you should give it a good oil change and top off the radiator.

Another good thing to do is to spray some oil to the cylinders.  Simply remove the spark plugs and shoot a burst of penetrating oil inside.

Before actually trying to start the car, use a socket wrench to turn over the crank shaft by hand a few times.  This should distribute the oil in the cylinders and also tell you if the engine has seized.

With all these steps complete, you can try to start the engine normally.  If it does fire up, keep your eyes on the gauges for a few minutes to make sure everything is running smoothly.

And don’t forget to cross your fingers!

- Ken the Car Guy