Posts Tagged ‘coolant’


Why Is My Engine Temperature Changing?


When I watch my engine temp, it seems like it gets hot, then cools down, and fluctuates like that for a while.  Is that normal, or is there something wrong?

Ben P., IN


When the engine temperature fluctuates like that, it could be for a couple of reasons.  It’s possible that there’s not really anything wrong and that the thermostat is simply giving a bad signal.

It’s also possible however that there’s a problem with your cooling system.  Blockages in the coolant lines could be causing this, or the thermostat could be restricting the flow of coolant when it gets a bad reading.

First step to fix this is to get the thermostat checked out.  This is a pretty simple and cheap procedure, and the replacement shouldn’t be very expensive if it’s needed.

- Ken the Car Guy


Why Am I Leaking Coolant?


My car seems to be leaking coolant from the reservoir, but only when the car is running.  Any idea what could be the problem, and how to fix it?

-Kimmy B., CO


If coolant is only leaking when the engine is running, your car probably uses a pressurized reservoir.  When the car is running, the increased pressure causes any cracks or weak hoses to spew coolant.  Your best bet is to get a pressure test to determine the location of the leak.

With the reservoir pressurized, it will be easy to find where the coolant is leaking from.  Hopefully it’s just a cracked hose, since a cracked reservoir will be much more expensive to fix.

- Ken the Car Guy


Can I Drive Without A Thermostat?


The thermostat in my engine is broken, so I pulled it out.  Is it safe to drive without getting a new one?

-David C., WA


While driving without a thermostat is possible, I wouldn’t recommend it.  The thermostat adjusts how much cooling the engine receives, therefore adjusting its temperature.

With the thermostat removed, there will be no regulation of coolant, and so the engine will always be cooled as much as possible.  This may sound like a good thing at first, but remember that engines have an optimal operating temperature.  Your lack of a thermostat will make it very difficult for the engine to reach that temperature.

- Ken the Car Guy


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