High rev engine start

[Kayman]

Hello,
I have a question on the internal engine lubrication on start up. I have a 08 3.5L Altima that revs up to about 2.5K on cold (80 Deg) start up. It drops back down normally. I have read where Nissan has done this initial high rev in order to get the oil circulating faster to minimize engine wear. I am concerned this might have an opposite effect if it's even trueand then wouldn't all OEM's do the same? I had a 95 Monte Carlo that started the same way and was burning oil at 90K miles so I might be a little paranoid.

 

[Trav]

They do this to get oil up the camshafts as quickly as possible, the cam lobes need lubrication quickly to prevent wear and in an OHC engine they are one of the last parts to receive the lube simply because of their distance from the pump.
There should be no increase in engine wear.

Edit: I just read AEHaas. Some modern cats use heaters but that could be a reason also.
Some injected bikes with no cat do the same thing, rev to about 2500 for a short time after cold start.

 

[AEHaas]

Actually I believe it is done more to warm up the catalytic converters faster. The oils will not heat up at all during this short rev as there is no load and besides it takes a half hour of driving to fully warm up an engine.

Let me add that this is one of the reasons I use oils that have a lower start-up viscosity, to get lube into parts under higher RPM, around the early engine use period.

aehaas

 

[il_signore97]

This is done by auto manufacturers as a way of quickly warming up the catalytic converters so that they can start cleaning the air. The reactions that occur within the cats are very slow when cold, and not enough to reduce pollutants to the proper amounts. So this high idle on start-up has really nothing to do with engine lubrication or otherwise.

It is kind of counter-productive in that regard if you ask me. However, living in Canada, during very cold winters, almost all vehicles (with the exception of some European cars) have quite a high idle on cold start-up. I used to have a Nissan Altima 3.5 SE (same engine as yours) and it would do the exact same thing. I had 250,000 km on it when I sold it (still running very well at that time for the most part).

Most European cars take a different approach, in which they use an air injection pump to force air into the exhaust during a cold start-up to increase the available oxygen, and thus speed up the reaction that way (which in turn heats up the cats quicker). They don't have to rely on the engine to do it, so my new car now doesn't really have much of a high idle (maybe 1100 rpm for about 15-20 seconds at worst).

In short, don't worry about it too much, and welcome to the forums!

 

[Hyde244]

Originally Posted By: Kayman
Hello,
I have a question on the internal engine lubrication on start up. I have a 08 3.5L Altima that revs up to about 2.5K on cold (80 Deg) start up. It drops back down normally. I have read where Nissan has done this initial high rev in order to get the oil circulating faster to minimize engine wear. I am concerned this might have an opposite effect if it's even trueand then wouldn't all OEM's do the same? I had a 95 Monte Carlo that started the same way and was burning oil at 90K miles so I might be a little paranoid.
Honestly? I trust engineers who know every spec of this car after years of research and design.

If you are truly concerned, use a 0 weight oil or synthetic that provides better cold start protection.

Otherwise, trust that the car companies probably do know what they are doing.

 

[SwampSurvivor]

It's for the converters. If you dump a bunch of unburnt fuel in it by running a pig rich cold engine at 2000RPM, it'll heat right up and last longer.

That's the reason I run 0w-20 in the winter. I can't imagine it's good for my engine to race at 2000RPM on a -20 morning!

The other thing that's annoying is this feature on a manual transmission. Trying to shift a a manual transmission on a cold morning when the engine refuses to idle below 2000 is a pain.

Even worse, I live on a hill. If I coast down the hill for a half mile or so, it's racing at 3000RPM by the time I get to the bottom! There's no way I'd be able to put an intake or exhaust on my car as I'd be getting tickets.

Same as I posted the other day- my Focus isn't loud, but my dad's F350 is ridiculously loud when it starts up and idles at 2000 RPM.

It seems that certain newer vehicles do not need to. Mazda plays with valve timing to warm everything up quicker on their skyactiv engine.

Thankfully, the Cherokee just idles at 1100 until it's happy.

 

[CHARLIEBRONSON21]

My 03 accord 2.4L did the same thing. Never had any problems while I owned it.

 

[ThirdeYe]

My '95 Integra does the same thing. As mentioned by a number of folks above, it's for emissions purposes. It warms up the catalytic converter(s) faster. Still on the original engine, transmission, and catalytic converter. Doesn't seemed to have hurt anything...

 

[440Magnum]

Originally Posted By: Kayman
Hello,
I have a question on the internal engine lubrication on start up. I have a 08 3.5L Altima that revs up to about 2.5K on cold (80 Deg) start up. It drops back down normally. I have read where Nissan has done this initial high rev in order to get the oil circulating faster to minimize engine wear. I am concerned this might have an opposite effect if it's even trueand then wouldn't all OEM's do the same? I had a 95 Monte Carlo that started the same way and was burning oil at 90K miles so I might be a little paranoid.


Don't worry. What the PCM does is the safest possible way to start the engine, my newer Chrysler products do exactly the same thing as do most rental cars I've driven. Its partially for emissions, but it also has a basis in lubrication. The brief moderately high RPM gets the oil pressure up before the oil film remaining on parts from the last shut-down gets scraped away. The worst thing you can do for an engine that's been shut down a long time (especially an old one with flat tappets) is to crank it with the starter until the oil pressure comes up.) The best thing of course would be to pre-lube it externally, but that's overkill in most cases.

I had a thread about starting my old high-school car after 8 years of storage recently. I cranked it two turns of the crankshaft to be sure the cylinders weren't hydrolocked for some reason (eg, coolant leak at head gasket). Then I primed the carb and fired it up as quick as it would start and left it on fast-idle. It only rattled for a half second or less.

 

[Brent_G]

My car idles up to 2k when cold, truck goes up to 2k when really cold, and bike up to 2700. I'm guessing its for a combination of lighting the cats off as fast as possible as well as warm the engine up faster than idle. My old Honda F4i would idle up to 3700 when it was it was cool out and that does not have a cat.

It will not hurt your engine at all especially in FL. My truck sees 2-3 cold starts a day in the winter, between 30 degrees down to -25 or colder. 140k miles and burns 1/2 qt every 5k. V10 Triton in a F350 tow truck that has ran 5w30 conventional its whole life burns around 1q per 5k that goes up to 1900 when cold. Modern engines are much more durable than we give them credit for. Oil has to be brutally cold to not be pumping through the engine, so while you are pulling your hair out fearing that every tick you hear is your cam lobes being wiped clean, rings scraping iron in dry cylinder - your engine is spinning away, bearings happy and lubricated, oil flowing though everything.

Ticks, taps, and noises that people always seem to get worked up and worried about on here are going to happen. A cold engine is always going to be a bit noisy until it warms up; Aluminium pistons expand differently than the steel cylinder, short piston skirts tap, a cold valve train clatters until everything expands and fits. Listen to a 3406 Cat start -20 with no block heater, you will run for cover and be certain there are people taking turns swinging sledgehammers inside of it. However that engine will run for a million miles sometimes.

Bottom line is something will kill your car long before whatever damage POSSIBLY happens with the fast idle and cold start noises. I would worry about the A/T way more than the engine.

 

[Kayman]

OK, thanks for the responses.

As long as I'm helping the environment!

 

[aquariuscsm]

Both of my 3000GT`s had very high rev starting. With 10W30 they`d have upper end rattle on cold mornings. With 10W40,they never had the rattle.

 

[cutter]

Originally Posted By: Miller88
The other thing that's annoying is this feature on a manual transmission. Trying to shift a a manual transmission on a cold morning when the engine refuses to idle below 2000 is a pain.


It's not too bad, I don't even use the gas pedal for the first 5-10 minutes while it's cold. Can never stall the car during this time, easy for first timers on manual even.

 

[SwampSurvivor]

Originally Posted By: cutter
Originally Posted By: Miller88
The other thing that's annoying is this feature on a manual transmission. Trying to shift a a manual transmission on a cold morning when the engine refuses to idle below 2000 is a pain.


It's not too bad, I don't even use the gas pedal for the first 5-10 minutes while it's cold. Can never stall the car during this time, easy for first timers on manual even.


Yes!

If I decide to go the other way to get on the interstate (flat road for a mile or so with some stoplights), I don't even need to use the gas to take off and get up to the speed limit of 30.

I'm starting to think this is actually a useful feature!

 

[Smokescreen]

I am lucky I guess, when I start any of my cars and they want to high idle, I put that energy to work and put it in drive right away and just let the engine speed coast my way through the community. By the time I get to the on ramp, my engine, wheel bearings, transmission...everything that moves/drives has sufficiently warmed up enough so that the smooth acceleration and stead state that is next is not any harsh adjustment and its ready for it.

 

[ARCOgraphite]

Originally Posted By: Hyde244


Otherwise, trust that the car companies probably do know what they are doing.
That Hilarious! I might argue using 0w wont do much compared to what running 1 step lower grade would.

 

[jrustles]

+1 for emissions

We had an 89 626 that would cold rev to 2500 even 2700 on the coldest winter days, and I promise you the crankcase was filled with something like 10w40 dino + OCOD

That engine ran excellent on it's last day. Sleep easy

 

[crazyoildude]

2500 rpm sounds a little high if you ask me is there a slight vacuum leak..
As an engine rebuilder i dont like the higher revs upon startup.Check for leaks and maybe have the pcm flashed

 

[CATERHAM]

My Bimmer does this on cold starts but only during the winter months when the ambient temp's are below about 50F.
I don't like it so in the winter I start the car in gear (clutch pedal depressed) so that I can put load on the engine a split second after it fires-up and bring down the rev's.
With the rev's forced down to a 1,000 rpm or less they will stay down after the load is taken off the engine.

 

[Brent_G]

Originally Posted By: crazyoildude
2500 rpm sounds a little high if you ask me is there a slight vacuum leak..
As an engine rebuilder i dont like the higher revs upon startup.Check for leaks and maybe have the pcm flashed


It is a bit high, but rereading the OP's question i'm not sure if he is talking about it peaks at 2500 rpm right after starts for a brief moment or if it is running there.

OP - Are you saying it goes to 2500 right at start and slowly drops to normal idle over a minute or so, or just a few seconds or so?