In Reply to: Re: not exactly posted by Les on September 15, 1999 at 07:21:58:
: Not exactly. Your car should not be running hotter on long drives because you have good air flow. If it does run hotter, you have problems. Engines may run a little hotter in stop and go city driving but not encounter higher oil loss. But highway driving produces greater pressures on seals and bearings.
Oops, what I meant to say was: driving on longer trips produces temperatures that are stressful because they are MAINTAINED for so long. Stop and go driving involves idling and accelerating throughout the rev range. I typically maintain over 3 grand while cruising on the highway, and this is the type of condition that can be detrimental to particular seals and gaskets that do not benefit much from airflow (i.e. headgaskets). Airflow would not have helped my exhaust gaskets (heck, I was going 90 mph!), but neither did the car's mileage or age.
The analogy I'll use is butter. Put in on a hot frying pan for a few seconds and it will start to melt. Turn off the heat or remove the pan from the burner, and the butter will re-solidify at room temperature. You can do this many times without completley melting the butter. But leave the butter on the pan for over a minute, and it will melt completely into liquid.
I think we're both in agreement about the probable nature of Paul's problem. The extended cruising is in fact stressing the seals, bearings, gaskets more than his around-town driving.
90 535iM, sharked, CCA