Questions and Answers

Engine Block Heaters

Q. Hi Vince, I have a 1999 Saturn SL. I live in the mountains in Colorado, where the temperature routinely drops below zero during the winter, so I had an engine block heater installed through the Saturn dealership when I bought my car. I had the impression that block heaters kept the engine (or at least the oil) warm overnight so that I could start driving right away.

However, I've found that I still have to idle or drive slowly for a few miles, until the needle on the engine temperature gauge moves ever so slightly past the "C", as if I had never plugged the car in at all. Also, it still takes forever for the heating system to kick in. Do you think that I had unrealistic expectations on what an engine block heater is for, or do you think it may have been incorrectly installed?

Love your column!

Thank you very much,
Tamara

A. Thank you Tamara, that's sweet of you to say.

We have the same conditions here in Minnesota. The temperature often drops below zero and stays there for weeks at a time. Block heaters are supposed to keep the engine warm. From personal experience, mine keeps my engine temperature at about 60 or 70 degrees. Heat is not instantly available, but it does warm up a lot faster than without it.

I don't know what you are expecting out of it, but basically most block heaters will keep the engine at between 60 and 70 degrees. The main purpose is to insure severe cold weather starting. It does this by keeping the oil from getting thick and helps the coolant from freezing. When you first start the car, you'll get some heat from the heater, but not a lot. My car has Automatic Climate Control and won't turn on until the coolant reaches a certain temperature. It takes about two miles of driving before it will kick on, whereas it will take four or five without the block heater.

Once you start driving, the cold air going through the radiator will keep the engine from reaching normal operating temperature. That would account for the long warmup time. Most people I know here use some sort of cover on their radiators to cut the air flow through the radiator and get the engine hot.

It certainly wouldn't hurt to have your block heater checked to make sure it is, indeed, working. There is nothing much to the installation. It's a sealed unit so there's really nothing that can be done wrong.