it feels like 100 degrees today and when driving today i noticed that the tempature for the engine readi never even got to half way today.It stayed near the cool side.Can this be a radiator issue,a sensor issue?IM not getting any codes.Maybe thermestat is off?Someone help me please.

You could have a stuck open thermostat, when was the last time you've changed it?

i have never changed it.is it a big job and expensive?

If you take it to a shop, they will charge you about 2-3 hours labor. The part is not that expensive. It's an easy job for a journeyman. DIY rating- intermediate.

thanks but i hope its my thermostat and not sometihng else

Feel the coolant hoses to see if they get hot. This will help you determine if it is an actual temperature problem or a sensor problem.

There is only one possible cause for an engine not heating up properly, a thermostat in the open position.

A sensor problem could be any number of things.

Thanks for the info.This might souns dumb but a thermostat stuck in the open position,does that mean its broken?Can it be unstuck?Is it safe to drive my car?Ive been driving it all around for 2 days with AC blowing and everything and it runs fine.Am i risking damaging my engine by driving it?

You are not going to wear out your engine in two or three days, but it will wear faster and won’t run as well if it doesn’t warm up properly. I wouldn’t take off work and rush right down and get it done, but I wouldn’t put it off forever either.

I doubt that there is much that you can do to fix a thermostat that is stuck. Even if you could, I’d rather do it right the first time to avoid having to do it all over again.

You are not going to wear out your engine in two or three days, but it will wear faster and won’t run as well if it doesn’t warm up properly. I wouldn’t take off work and rush right down and get it done, but I wouldn’t put it off forever either.

I doubt that there is much that you can do to fix a thermostat that is stuck. Even if you could, I’d rather do it right the first time to avoid having to do it all over again.

Indeed. It's a cheap part that is supposed to be swapped out when it fails.

You are not going to wear out your engine in two or three days, but it will wear faster and won’t run as well if it doesn’t warm up properly. I wouldn’t take off work and rush right down and get it done, but I wouldn’t put it off forever either.

I doubt that there is much that you can do to fix a thermostat that is stuck. Even if you could, I’d rather do it right the first time to avoid having to do it all over again.
Thanks Dave.I think you have answered every question about every problem about my car and you have been right every single time.You are probably one of the reasons why my car is running in good condition and in all honesty you have literally saved me lots of time and money by avoiding mechanics and crooks analizing everything.I wish it was like that with the forums i use to be a part of.
You are a great person!

Thanks. I don't claim to have all of the answers or to alway be right, but I try to help when I can.

As for the thermostat being inexpensive, they typically are. At least with most cars they are five or ten bucks. Everything seems is more expensive if it is for a BMW though. I have never replaced the one on my '98 750iL, but the one on my '88 750iL was somewhere around $100 just for the part!