Warming Engines and Short Trips

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Jun 8, 2002
Elizabethtown, Pa
You are not gonna' heat up the engine enough in 10 minutes of driving to get rid of the extra fuel/water that will come from extra idling. I can safely say that bc of a coule of oil analysis I took without a half hour drive.

But having said that; it probably doesn't matter much either way when only doing a 10 minute drive. Just an opinion though.
In the total package you gain nothing. If you take the fuel costs vs. the benefits (probably none during your ownership) ..why bother?? Essentially you exacerbating an elevated wear situation with extended fuel dilution properties. If anything ..you swap the $$ into more frequent oil changes.

The solution (contrary to popular belief - there are somethings that can not practically be remedied) would be to employ the sensible use of block and/or pan warmers. These too will incur some cost in both their purchase and operation.
My rule of thumb, idle till fast idle is safe for tranny and heat temp gauge barely moves, at this point I believe engine is ready for a light gentle load. Study how your engine operates or is engineered, my Nissan will fast idle 1600 rpm until the heat gauge barely moves and idle reduces to a respectable 1000 rpm and ready to shift into Drive safely when cold and tight, normal warm idle is 750 rpm. My other older winter packaged Nissans/Datsuns used to do 2000 rpm for 5 minutes in -35F before reducing, My 1980 Datsun 720 series has done this decades in our cold climate and still running great.

Idle and drive off gentle with heater off and window open to avoid fogging up, heat off greatly speeds up warming at idle/drive off, also idle in neutral to speed tranny warm up. This all works based on my personal experience based on 3 decades in my climate.

I read the recent
topic on the pros and cons of warming an engine before heading off. Seems to be a good, healthy debate on the subject with most believing it to be bad for an engine and some for the environment.

Environmental issues aside, I propose for short trips it is a good idea to get some heat in the engine before heading out on your 10 minute commute to work/store/etc. This way oil has a better chance of making it to operating temp to get the add packs working.

My $.02.

This seems to be one of the the more controversial topics on this board; which is why I kept quiet about it during the last thread that ran about it. Before I say anything, let me get my asbestos flame retardant suit on first.... ok now I'm ready.

All the cars I have ever owned, I've given them a nice long warm up to full operating temp before leaving the house. When I say operating temp, I mean 180F. Unless of coarse there is a big twister headed my way, at that point I might high-tale-it cold turkey.

I firmly believe this is healthy for all engines. Everything from a Northstar to a Briggs & Stratton. My Buick has both analog as well as a digital water temp guages; so getting it up to operating temp is a piece-a-cake. And once under way, it has a "smoother feel" about it, as opposed to driving it cold turkey.

Fuel delution? Yeah, maybe on a '70 Duster sitting on the drag strip with an over jetted Holley 850 at idle for 30 minutes. With modern computerized fuel injected engines kept in good tune; this doesn't happen.

Moisture in the oil? All the more reason to get to full operating temp and burn the moisture off.

Operating temp: oil is nice and "fluid" going where it needs to go effortlessly, fuel is atomizing properly, piston rings to cylinder clearances are at optimum distance for better compression and a
cleaner burning engine.

DISCLAIMER: just one man's opinion, treat your car however you want.
I dunno goldenrod, I have a saab and they've actually increased blowby in their new piston designs in the name of lower friction. It's made fuel dilution MORE of a problem than on my older 900.

Everything I've always read points out the main reason though is that idle doesn't warm up the oil and engine as efficiently as getting in and gently driving away ie it gets NICER and MORE fluid when things are stirring at 2-3k rpm vs. 800-900 at idle.

I don't worry w/ warming and given the small quick spooling turbo on my car, I don't have to tach over 2500 anyway to sail away from most intersections. Course, that turbo is heating the oil pretty quick anyway!
I think Gary had it mostly right, but went a little heavy on the 'costs'. OE block heaters for our Sube's are < $25. As far as operating costs, I can get my engine temp up to 90F for less than $0.08. Car reaches 185F in half the time than when I forget to plug it in.

Placement of Subaru block heaters are a thing of beauty! I've done 4 and each time it takes me longer to replace the antifreeze than it does to swap the heater for the "plug" [I say "plug" 'cuz I don't know what else to call it, it's the size of a large freeze plug, but a little thicker and threaded].

Engine temp @ 90F vs. 30F [attached unheated garage] for less than 8 cents is worth it too me, not to mention MUCH faster heat for the passenger compartment!

I have remote start in my vehicles.
What a great feature!
I've always warmed up at least 5-6 minutes in cold weather and never had any problems because of doing so.
It's worth the cost of the fuel to get the lubes circulating and the inside heated up faster too.
I idle for about a minute in warm weather too.
Goldenrod, you are fearless with that post. I could not go to that extreme but I dont loose sleep at night with a 7 minute idle in -40F, 3 minute at freezing with tranny in neutral and heater off.

For 3 decades from single, dual and 4 barrel carbs to now computerized fuel injection idling, I have never torn down an engine in my extreme cold climate, I get 300k +. All my buddies who have driven their vehicles successfully 3 decades in our climate will not go out and drive off a frozen vehicle either.

My father started a 1966 Ford Truck up north every day in winter with an ambient temp of -45F to -50F. With blockheating he would idle that truck 15 minutes every morning, that truck went 1.5 decades in hard service. I used to sit in that truck as a kid on a froze rock hard seat thinking it was going to snap like a pretzel driving off. No syn oil used then in late sixties/seventies on that truck, it was still running in 1981 when mine shut down.

Miners who had to cross Lake Athabaska on winter roads with mine supplies in -45F on a three day trip had to idle gas trucks all night with tarps on engines to keep them from freezing up, those trucks did many hard years service then too. Those were trucks from 60s with crude carburation.

Colt, I dont have a remote starter, I do use heat pad, 0-30 syn oil and blockheater, I echoe your idle time on cold weather, I also warm up that engine in summer too and still drive off gentle in 100F while still in high metal wear zone below 160F. With todays overhead cams and busy upper end, I like to know that oil is reaching everywhere and getting add pack warmed and working gentle up there at an idle at start, not on a load. That is my concern on not idling. Fully hot, I idle 30 seconds after a shutdown before drive off to insure that oil is completely circulating in pressure up.

When one lives in a cold climate, good habits follow into summer, if one drives off gentle cold all winter, that habit seems to stay in summer too, not a real evil in my opinion for the drive train.

There are too many variables when people post from California to Alaska and inbetween on this subject. Climate, aluminum/cast blocks, syn or dino oil, pad/blockheaters, access to traffic on 80 mph traffic or quiet slow town street for drive off. Many more I probably missed, one has to take all into consideration and do what works best for situation, my motto is "if aint broke, dont fix it" unless you can afford to experiement in driving off on a frozen stiff solid hunk mechanization, I have better places for my money.

I do spend on pad heaters, best syn oil, fuel for idle, my wife's and my cost on wages having our vehicles hooped one day or two hurts, + $70.00 per hour mechanic rate and new parts. Small price to pay in "tried tested and true" idling to keep vehicles working decades on end & keep working and playing inexpensively in long haul works for us.

I wont give up proved success with thin skin, too expensive a gamble for me.

I am bit confused about this idle 5-10 min business. Generally I have to stop at stop signs and a couple of traffic lights, so you will idle anyway once you start driving. I will idle for max 1 min and start driving gently, easy on throttle. By the time I get to the highway or 80km road I already idled 5-10 min at traffic lights, stop signs, etc. So there is no point idling in parking lot as you'll have plenty of time to idle at traffic lights.
But when you idle at those first couple stop lights, it'll still be freezing cold in the car. I'd rather idle at the first stoplight with heat coming out the vents! I agree ENTIRELY with Cyprs. If it's -10 in the morning, no way in heck am I gonna start and and drive off immediately. I have to let it idle for 15 minutes or I can't even shift gears with my manual trans.
I think it's best to idle for a little while (1 minute if below zero degrees F) and then just drive off easy. By easy I would say to speed up slowly and smoothly, and keep the RPMs < 3k. Remember, wear levels are at their peak when the engine/oil is cold, so to me it only makes sense to get it up to operating temp ASAP in a sensible and delicate manner.

When it's warm out, I just let it idle 15-30 seconds so that I get oil everywhere it needs to be, and then just drive off easy.
I think to idle or not to idle is becoming more controversial then asking whether SX-UP is better than VSOT, or if T&SUV is really the same as Delvac 1 : )

I used to idle my engine until I read here that your truck or van will explode, and the fenders will fall off : ) Seriously, I think idling for a little while in cold temps doesn't hurt anything. Like everything else, there are compromises to be made concerning how to prevent engine wear. Everyone has a different situation for driving in cold temperatures. Whether you have to get on the interstate within 1/4 mile, or whether you can drive very slowly for a few miles to give your oil a chance.

I think a good all round answer to the idle question is for everyone to buy a oil pan heater. There cheap to buy, and cheap to run. It makes a tremendous difference starting your engine during the winter with warm oil, even with a 0w- xx. It's amazing how much quicker and easier my engine starts with my pan heater plugged in.

After I start my engine, I let it idle between two and five minutes during the winter. Sometimes, I'll just depress the pedal to reach 1000-1200 rpm, after letting the engine idle at the normal 700 idle for a few extra minutes if it's really cold out. I'm more concerned with my EGR valve sooting up with extended idling than getting any fuel in my oil. Diesels warm up differently than gas engines. You really do have to put a light load on a diesel from what I understand in order to get it to start warming up sooner.

I see nothing wrong with idling an engine for up to five minutes during cold temps whether diesel or gas. The key of course is to drive very gently until at least your water temp is normal, then you know your oil is not too far behind.
I idle at least a minute to make sure the oil is flowing enough not to open the bypass valve on my oil filter. I have an aftermarket oil pressure guage and my fiters valve opens at 15 psi (on paper). Just driving off normally like a grandma with Grp IV synthetic without an idle puts me at 22 psi at 2000 rpms. Who has an opinion on this? It's a PureOne filter FYI.
Ya know, at the start of this thread, I was a smug non-idler thinking you guys were nuts. I've heard repeatedly and read repeatedly that you need drive off to bring the car up to temp faster.

Well, I was browsing thru my old 1982 BMW 320i owner's manual last night and found the recommendation to start and drive off. Only...it said nothing about being best for the engine. It was to get enough heat going to light off the cat!

We all know what's good for emissions may not necessarily be best for engine longevity. Have we non-idlers been had in the name of saving the dolphins?

Have we non-idlers been had in the name of saving the dolphins?

Saving the Dolphins is is important too. Even the hard core idlers and non idlers on BITOG are more closely aligned than most of the world, in that both camps here are concerned with the ramifications of their actions with respect to engine wear.

There are many other issues which contribute to the advance or reduction of engine wear. The idling question is one of dozens of issues we must contend with. It's possible that one individual could get the idling issue totally wrong ' what ever that would mean ' yet get every other issue totally right, and have the best UOA's with an engine that outlasts all others engines.

Just like everything else, the truth in idling probably falls somewhere in the middle. Remember what Grandma said......beside you better quit that or you'll go blind : ) She said it's OK to idle your engine Sonny......just probably not as much as some, and a little more than others.

tamu_ You have a valid point about bypass pressure......honestly look into a pan heater.

Brian : Do I feel a disturbance in the force ?! : )
Too funny.

My cars are for the convenience and comfort of my family and myself. Who cares it if it wears them out slightly faster? They're only cars. They exist to serve me, not the other way around.
I read Islander's Shell page, made sense to me. In that article it states there should be no revs during cold warm up.

My Nissan will jump/spurt to 2000 rpm immediately at turn of key and then reduce to solid fast idle at 1600 rmp when cold.

I have been told in this forum this quick immediate spurt in rpm is for the cat, toyotas and others do the same apparently.

Nissan engineers must have reasons for a cold immediate quick spurt of rpm like that on the instant the key is turned on. Could reason be for immediate quick oil pickup/flow? just guessing

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