Engine Temp - Running Cold??
 

'97 328is

Folks,
I added some coolant recently just to top off for a longer trip. I've since noticed that my temp gage is running colder than it should, even after the engine has been running for a while, like 30 minutes or more.

I started thinking, & realized that the pre-mixed coolant I added was orange in color, where as the original coolant was green. Is there a difference to these coolants, & if so, what are the effects of this in the car? The temp needle is still between the center has marks of the gage, just on the cool side of center.

Is this gonna cause problems, & should I have it drained & refilled?

Thanks.

Color is used to determine the type of fluid. Some types are mixable. Its best to just stick with one type and keep and extra partial jug around.

Search Zerex and Prestone websites to find out to see what each color means and check for compatibility.

How cold is it running? If its just a needle width, are you sure it isn't your imagination?

Naw Jeron, it's not my imagination. It isn't to the cold side of center all the time, sometimes it's right at center, sometimes its on the colder side, sometimes I can see it move around between the two.

The temp gage has the two white line hash marks in the middle marking the "acceptable" temp range before going to either too hot, or cold. The needle always stays between those two center hash marks, but I've never seen a car run colder than it should after it has been running for 30 minutes.

I wasn't sure if the two color coolants use different chemicals, & the are reacting adversely.

The needle stays at TDC for a range of like 30 deg F, its about 172 to 202, IIRC.

So for you to see it move left and right it would have to be having huge temperature swings.

Maybe an electrical issue?

I was told that BMW's take a specific type of coolant, & if not used it could cause engine block damage.

I getting concerned as to what I may have added. I added Zerex extreme extended life ready to use coolant, & only added about 2 cups worth. Like I said previously, It was orange in color, where as the original coolant was green.

Seriously, any thoughts? I'm thinking I need a drop, flush, & refill.

BMW does have their own special fluid. There are fluids by Zerex and Prestone that will work fine as well. Zerex has a chart on their website that lists their BMW compatible fluid.

The reason for the color is to keep you from mixing fluids of different type. In the past this was a big problem because some fluids were markedly incompatible. I think this problem is not as bad with the new formulations.

If it were me I would do a drain, flush with water and refill. I would use BMW $20-30 or Zerex $10-20.