Short driving distance bad on engine?

[bobby5]

I was wondering if driving short distances without the engine reaching full operating temperature is bad on a engine. I always herd that heat kills engine then why is it bad to drive short distances, the engine is running cooler since it hasnt reached full operating temperature?

[kdm101]

The problem with running engines for short durations is that byproducts of combustion start building up inside the engine and in the oil. Most notably is water vapor. In a cold engine, that water vapor will condense, and usually gets trapped in the oil. When that happens, rust and sludge develop. Sludge is your engine's enemy! Permitting the engine to reach normal operating temperature is what helps to purge these byproducts before any damage can occur.

 

As far as heat killing an engine, that would be anything over normal operating range (say 240 degrees and up). Keeping that engine at proper temperature is controlled by, of course, the cooling system, but also by keeping the oil at the proper safe level. If the oil level falls too low, it begins to rise in temperature, and as that happens, it breaks down faster. This break down in the oil can also cause sludge (like above), which can block oil passages, which increases friction, which increases heat... which is a vicious cycle.

 

If you're running lots of short trips, just be sure that the oil and filter are changed regularly. Occasional trips where you can get the engine exercised to it's optimum will also alleviate those issues as well. Once per week could be all it takes.

[asepgrad98]

I always herd that heat kills engine then why is it bad to drive short distances, the engine is running cooler since it hasnt reached full operating temperature?

 

yes, its a cause and affect type of thing. You got to decide witch is worse

[geobar5]

Just another consideration: in the past, there was always a problem with engines that had aluminum heads on iron blocks. Since aluminum expands about 20 times the rate of iron, conventional gaskets were scrubbed to destruction with repeated hot/cold cycles. The new multi-layered-metallic gaskets were developed to solve this problem, but I would still prefer to minimize these cycles. This expansion thing is also why you need to carefully tighten aluminum wheels so much.

[slemmer]

The 'short drive' timing is also subjective. I've heard that you should be driving for at least 20 mins to get the system up to temperature. Many short haul drives resulted in mufflers rusting out pre-maturely. With the stainless steel units, it's not shown externally, but the internal components may be breaking down.

 

I'm of favour where you should at least once a week take it on the highway to burn off any lingering sludge and moisture in the system. Frequent oil changes would help too.

[Black02Silverado]

If you run nothing but short trips in cold weather or even in the summer where the engine does not reach full operating temperature, then frequent oil changes are a must. Running short trips is worse than running at 70mph for days on end down the interstate. As stated above the build up of sludge and acids will really do a number on the inside of the engine and keeping the oil fresh with frequent changes is required. Synthetic oil helps to keep the contaminates down but not much better than conventional oil. Running conventional oil at 2000 to 3000 mile oil change intervals would be the best rule of thumb.