thermostat problem

[ponsford26]

hi all hope someone can help

I have a 1999 328ci coupe, my lower pipe on my rad is only slightly warm, i know the thermostat is the propblem, but would this have a affect on the running of the car ie, slight engine misfire, and running rough been pluged in and its sucking in to much air, when warm you can here the air aswell, its only when its warm tho.
hope someone can help

thanks again

[FCPGroton]

Absolutely. Is the car running hot or cold?

[ponsford26]

Hi there it up to normal temp but the lower rad hose dosnt seem to get at hot as the top one i noticed theres a sensor in the bottom hose

[drz]

If you are in the northern hemisphere and outside the tropics, weather is getting colder outside. Your thermostat will spend a longer time closed than it would in the summer months. Thus, the differential in temperature from one hose to the other will be more noticeable. If your temperature gauge is showing normal operating temperature, then everything should be okay.