VisualEchos

I was just wondering, is there any truth to that old saying, with reference to running a car hard and then just shutting it off, that is detrimental to the engine? It's obvious on turbocharged cars because of "coaking" (cooking the oil to the bearings in the turbo because of the small ammount of oil on them and the high temps), but is it bad to run a N/A engine hard and then just shut it off? Also, I've seen no mention of the very loud snapping sounds coming from the car (under the passenger side I think...heatshield?) after the car has been run hard and shut off, am I the only one getting these sounds? Any reply will be appreciated.

Andrew

pellisS2k

I dont know about the engine side of things, but be careful to not use your hand brake when parking if you heated the brakes up significantly.. warpage awaits.

austincrx

There are some interesting theories on 'heat soak' that you should read up on. I don't know of any off hand, but a quick Google search will yield lots of results. Some believe it is better to leave the engine on and even turn on the A/C (to begin the radiator/condenser fans), which is my belief (it can't hurt). But others still believe that heat soak isn't an issue and that as long as the engine temp and water temp aren't high, then go ahead and turn it off.

INDYMAC

The snap crackel pop noises are from dissimilar metals on your exhaust cooling at different rates.

The recommendation to allow your engine to cool down before shutdown is similar to the coking issue on turbo bearings, but not quite. When you shut down your engine most of the oil quickly returns to the sump. But some sits in little nooks and cranies that might be hot spots. You want those spots to be as cool as possible when shutdown occurs. This will help to prevent deposit formation (think oil sizzling).

Saki GT

Unless you are generating some high temps like via a turbo, heat isn't really an issue IMO. After a hard run I do idle the engine for a bit, but its not based in anything other than preference.

The e-brake shouldn't be used after spirited driving as it will not grip as things cool down.

SpudRacer

Yep, some factory turbocharged engines with water cooled turbo bearings specify a cool down period and warn against just stopping the engine abruptly after hard use. On the other hand, I've ignored the manual pretty religiously and driven turbo cars up to 150,000 miles without any failures.

Slithr

Coking became much less of a problem with the advent of synthetic oils.

s2kpdx01

also, if you are driving it 'hard' on the street you are probably going to need to drive slowly back through a neighborhood or something to your house before you shut it off. Even on track you take at least one cool down lap then park. I've never driven my car really hard and then just instantly turned it off. It's not an issue.

Presto123

Best thread title ever.

SpudRacer

Yep, that and Mobil 1 are why I never really worried about coking the bearings on the turbo. I've always had at least a few minute's drive from any highway to my house.

The heat issue (lack of) is one of the side benefits of a supercharger that I hadn't really thought much about before owning one. They aren't exposed to the sort of temp extremes that a turbo sees with exhaust gases. But in reality both these technologies are pretty mature at this point and both can be very reliable in factory solutions.