lldknyll26

After driving for 2 hrs straight on the highway, my friend had recommended me to cool the engine prior to turning the ignition off. is this really necessary? Its somewhat of a same concept of warming your car. Regardless i do warm up my car for a minute or two in the winter time but other than that i hardly ever warm up or cool my engine before or after. I've read an article how new model cars do not need to be warmed up during winter season. Since warming isnt necessary anymore, is cooling recommended? I still warm up my car even after reading that article but not quite sure about cooling the engine.

ankur914

sorry, but...wth is cooling the engine? Letting it idle in park/nuetral before you shut it down?

ankur914

damned 5 minute rule..

If coolling down is what i think it is, ive only heard of doing this in turbo equipped cars to allow the turbo to cool properly to prevent coking inside of it. Otherwise, i dont think you have anything to worry about since we are naturally aspirated.

greco9885

iTrader: (1)

correct. for N/A cars its pointless

jvinhj240

I think he meant by cooling is let the car rest instead of let it running for long hrs.

JTS97Z28

iTrader: (4)

Your friend seems to be pulling crap out of his you know what lol.

There is absolutely no reason to warm up or cool down a engine in a modern car. During winter they even say to simply start it and drive away normally until at full operating temp.
As far as cooling down lol. Umm no, put it in park and turn it off.

princelybug

iTrader: (16)

No need to cool down our cars.

But, I warm my car up every time, for about 60 seconds.

Will Y.

No.
If your engine temperature is on the high side, the engine fans will continue to run for a short time after the engine has been turned off.

ray-ban

Warming up the car in the winter isnt a BAD idea. For newer cars, it's not necessary. You can start and go, but keep the rpm's down until your oil temp rises. That's about all I'd suggest.

I warm up my car in the winter all the time, but more to get the cabin warm and windows defrosted. Warming the engine is just a bonus.

sixsixfour

you dont need to do it. even modern turbo cars like the GT-R and the Evo X leave the fans running even after you shut down the car if the engine temp is too high. the days of using a turbo timer on these cars is all but gone. NA cars like the TL dont need a cool down phase. you just park, shut off the car and go. cooling down is just a waste of fuel and you get 0 MPG.

PhilB81

You run a turbo timer to keep the oil pump going, not to keep the fans on the radiator spinning.

And on a naturally aspirated engine I wouldn't cool the engine off. On a turbo engine I would only bother after some sprited driving.

LoveMyTL-S

I actually cool my car down when I first get in it. Gotta love A/C

01tl4tl

IMO
You should be waiting 30-60 seconds on start for full oil pressure to build up before putting the car in gear. I cring watching the neighbors jump in a car- puff of smoke from the exhaust, flash of brake lights going into gear and they are gone~
that shortens bearing life big time!!

If I've been hot footing it around the mountains or racetrack and come to a rest, letting it idle 30-60 seconds to let things settle before shut down is normal,,
actually Im putting up the sunshade and turning off stereo and ac, then engine off and leave car.

The radiator fans are not to cool the engine, but the radiator
When you shut down- there is a temperature spike as the water now sitting in the block gets hotter. When running, the water pump moves hot block water to the rad for cooling~

Now the res bottle comes into play- notice the cold and hot lines on it- hot expanding fluid gets pushed out of the radiator into the bottle- when it cools its pulled back.
By the sensors running the fan a minute (temp based, not actual time)
it pulls cooler air thru the rad to counter most of the temp spike

If your driver side fan runs for several minutes- check for fan temp sensor failure

Turbos and timers- dont know if technology has changed,,
It used to be 2 minutes at idle speed to cool the oil going thru the system.
thats from misubishi and rx7 turbos and racing experience many years ago.

Extreme Hot oil causes a burned bearing surface, called Coking the bearings

Timer and an electric oil pump that taps into the system push oil at running pressure thru the turbo and engine bearings allowing the oil time to cool safely-
Used on pre-start and shutdown on many race cars and airplanes- run 2-15 minutes
Starting an engine with full oil pressure is a great thing to make it live long and prosperous
If your car doesnt have an actual pressure guage- the idiot light goes out at ~10psi
you should have ~30 before driving...

IMO give the engine the best care and it will outlast me and the next lucky person to get my TL--well past 300k miles is normal for a loved acura engine

SouthernBoy

I think you people are missing something here... the real reason that a "cool down" period was suggested. The valves.

Driving at highway speeds for a period of time will heat the exhaust valves to a dull cherry red color. They get hot. The idea for the cool down was this. If you just pulled the car off to shoulder or rest stop and shut the engine down, the potential of warping or cracking existed on the valve faces. This has largely gone by the wayside.

But it is not going to hurt anything either if you do this and just let the engine idle for perhaps a half a minute before shutting it off. Most people do something much like this anyway after a drive on a freeway. They pull into a gas station, fast food place, or a rest stop and by the time they've parked their car and turned off their engine, they have performed a cool down anyway.

01tl4tl

lets go with that--
for the sake of non believers: its just the time to deal with ac-stereo and window shade -(if applicable)-
has nothing to do with engine health

01tl4tl

I am guessing that back in the day.. before unleaded gas forced a change to hardened steel valves and harded streel valve seats,,,the metals were more temp reactive as SouthernBoy said
Modern cars are different in many ways, but old school precautions never hurt

SouthernBoy

Yeah, it can't hurt and may still help some. When I am on a vacation road trip, but the time I have pulled off of a superhighway, it could be two or three minutes before I shut my engine down. And driving at the moderate/slow speeds on the way to a gas station or eating establishment does good things for the parts.

sixsixfour

well that's a given. when i get off the freeway on my way home, i have to pass through a few lights before i reach my neighborhood. speeds are around 40 mph and the stoplights are pretty bunched up together. by the time i reach home, the car would've "cooled down" enough that i simply reverse the car into my garage and shut off completely.

the fact remains that if modern cars are required to cool down for fear of some engine damage we would have seen/heard a lot of it.


as a side note:

01tl4tl - on the Evo (and to the best of my knowledge on the GT-R), the fans run along with the coolant pump. the system circulates coolant through the engine even with the ignition system turned off. this is to cool down the internals and prevent the oil from coking.

people that install turbo timers (especially on older cars) fail to realize that keeping the engine running may circulate the coolant, but if the coolant itself isnt being cooled down it retains more heat and brings it back into the engine. its better to run a fan controller and an upgraded cooling system to better keep temperatures under control.

I hate cars

It's not necessary but it's not a bad idea.

As it was mentioned, exhaust valves can warp, this is extremely rare today with much better metals being used.

The engine runs an average temp of 198 degrees but there are localized hot spots that get in excess of 1,400 degrees. It's good to let everything cool down to a reasonable temp. When you shut an engine off that was on the verge of overheating, the water in the heads can boil, the exhaust valves that are still open can warp, ringlands no longer have fresh cooling oil and coolant is not being circulated around the cylinders. With our relatively new TLs, this isn't much of a concern but my old beater that ran on the verge of overheating all the time would boil over about 45 seconds after I shut the engine off.

And about the warmup, it's proven that a lot of wear occurs not at initial startup but during the 20 minute warmup process. A modern car will run great during this process unlike the older carbed cars but clearances are far from ideal until it hits full temp. Oil pressure and flow to everything is nearly instant but it's good to take it easy until the engine gets up to full temp. Keep in mind the coolant reaches full temp much faster than the oil.

PhilB81

You know I really find it lame that cars have water temp gauges but no oil temp. The TL's temp gauge is pointlessly large in my opinion, I would have really liked a oil temp in that cluster too.

SlowRiderr

Usually cars with un-water cooled turbos have a turbo timer so that the oil doesn't coke up (journal or ball bearing turbo) after a hard run. Water-cooled turbos are better about this

I hate cars

The problem is that the water quickly boils away once it stops flowing and heat transfers from the turbine side into the center section. IMO, Porsche does it right. Water cooled turbo with a small electric pump to circulate coolant through the turbo after the engine shuts off.

Even so, with a standard turbo, all it takes is driving nice for the last couple miles before you shut it off and you'll be fine. Same with the entire engine.