Overheating while idling
 

2006 boxster. I was warming up the car in driveway for about 20 minutes as it hadn't been driven in about a week. When I got back in to put in garage the red warning light came on and the the temp needle went all the way to the left. Could the car overheat that way. Temp here about 30F.

If the electric fans don't turn on then yes it will overheat at idle.

Don't do that!

Idling for extended periods is very bad for the engine!

Your coolant and oil pumps (and consequently your coolant and oil flow) are RPM dependent.

Even if the fans are working properly, you're not providing enough flow to properly cool and lubricate the engine.

Prolonged idling is also very bad for the cats - expensive items to replace.

Cheers!

I idle my cars until the temp gauge starts to move. Cold oil in a revving engine is far worse than in an idling one.

agreed, but 20 minutes? that's a bit long...

I don't think 20 minutes is too long, I mean, don't you think that Porsche would make sure that its cars could operate at idle without hurting themselves, it would be very poor engineering if that was not the case.

I think the problem is leaving it unattended.

I do not let my cars idle without watching the temp gauge because I have had too many Land Rovers whose clutch fans have failed. Just experience I guess. When we go offroad, I leave my truck running all day, but I keep an eye on it.

And how are you supposed to navigate city traffic without idling for long periods while stuck in traffic jams. It just makes no sense that you should not idle a modern EFI engine.

Whether or not you should warm up your car, it sounds like the original poster was just letting it idle and then putting it back in his garage.

Don't do that; you just load the oil up with nasty combustion by-products, and then leave them there to etch away the insides of your engine.

Buy a battery maintainer, only start the car if you are going to drive it for more than 30 minutes.

-james

That's not really they best use of time or gas, plus in some cases leads to carbon buildup and/or cat problems. Just get in, start it up, and drive easily until it's warm. The engine, oil, and other stuff like the transmission that also need to warm up gets up to temp much much faster this way, not to mention the interior heat.

If you're really worried about it, give it 30 seconds and then go.

Also, just because the coolant temp needle is at ~180 or whatever you consider "warm" doesn't necessarily mean that the oil is anywhere near operating temp. I'm not sure on the Boxster, as I don't have an oil temp gauge, but my old VR6 would take about twice as long to warm the oil as it would the coolant. The Boxster has almost twice the oil capacity, so I'd assume it takes even longer.

I used to subscribe to the 30 second thing until I read this.

http://www.ferrarichat.com/forum/faq.php?faq=haas_articles

It is a fantastic body of knowledge.

First WELCOME to ayacucho! :cheers: :cheers:

I would agree that long idle time is not advisable, but don't think the engine should overheat unless there is a problem.

Not sure how well modern cars handle rich idle control, but my -6 would get the cylinders washed down with excess gas if I did that long start up idle.

Check coolant level. Check for cracked plastic container as that is frequent problem. Wet carpet?

The check the radiators for blockage from leaves or street junk. Clean if needed. Remove front bumper cover to get at them easily.

Then check to see if the fans are operating. You can hear them running.

If that doesn't clear the problem and it over heats again, I'd take it to a good mechanic.

I have a rule that I run my car until it reaches operating temperature and then drive home for even an otherwise quick trip into town.

That looks like a good read, but unfortunately I don't have time to read the whole thing right now. I'll have to give it a complete look later.

I did give it a skim (a thorough skimming, but skimming nonetheless), and I still disagree with the warm up idea. Warm up before going WFO or even a bit heavy on the throttle, sure. It's not like idling your car in the garage or driveway for any length of time beyond the time it takes to get situated, put on your seat belt etc, is a practical way to get your oil circulating properly. On truly cold days, ok, give the oil a bit to move around, but beyond that, I don't agree.

Thanks for the help, I won't do that again. I waited an hour and a half and restarted the car and the warning light is still blinking. Manual says blinking light means low coolant. Coolant is full, no leaks. Not sure now, may have to bring to dealer to check. Once again thanks to all for the help.

The whole point to idling a car for about 30 seconds after startup is to allow the oil galleries to pressurize and float the crank. This is why the DME operates in Open Loop for 30 seconds, it then switches to Closed Loop operation to facilitate driving and controlling emissions. After the slight warm-up, you want the engine revving higher so that oil is flowed to the top of the engine and lubes and cools the head, cams and valves. The oil pump is not at maximum pressure or flow at idle, nor is the coolant pump.

Most of the caution about driving at low throttle until things warm is related to the transmission which does not produce heat from combustion as an engine does, but only warms from the friction created from it's internals by operating in gear.

Also, cold starts, and cold starts in cold climates, is exactly why multi-grade oils were produced and these work quite well. Excessive warm-up and idling is a thing of the past.

So far as Porsche engineering is concerned, your faith in it doesn't make it so. These are the same folks that brought you IMS and RMS issues (what are they on their 4th or 5th gen. fix?).

People believe what they want, I mean there's still a Flat Earth Society... but that doesn't make it so.

Cheers!

Thank you for the advice.

Did you read the article that I linked to? The good Doctor makes it abundantly clear that the problem as he sees it is cold starts. If he is mistaken then I certainly would like to know about it.

You read and you read and you talk to folks and then you make policies regarding what you do and how. That is what I have done.

Hydraulic lifters like oil and they like warm oil. I realize that our German boxers are not V8s and am willing to change my policy if evidence is produced to the contrary of what is the basis for warming my engines.

Give me some data.

I don't want to get into a long dragged out discussion on this. Academically, some arguements look good on the face of it.

But one thing the 'good Doctor' is discounting are the millions of cars operated each day, including those in freezing climates, where most drivers pay little if any attention to warming from a cold start. And most of their engines operate well to the extent of their design life. And, for those which aren't, there are too many variables involved such as driving style, abuse, avoided or poor maintenance to point specifically to poor startup procedures alone. His 'theories' just aren't born out in real life.

If it were such a problem, the roads would be littered with cars with blown engines and this is just not the case. There is proof all around you.

Cheers!

I think it is a case of "if the poison doesn't kill you the cancer will".

Wear occurs before the motor is warmed up at startup. We agree on that.

Cold oil is more viscous, I think we can agree on that.

The question is:

Which is worse for your engine, insufficient lubrication due to increased viscocity of cold oil, or the effects of inefficient combustion on your oil and catalytic convertor.

The lack of cars on the side of the road is not sufficient for me to change my views on this. The lack of evidence is not evidence to the contrary.

I have two cars that I have owned since new with over 200k miles on them on original engines.

Exactly. The FerrariChat post mentions that after a certain pressure, thicker/colder fluid (oil) doesn't flow any more, which may well be true (I'm not big into fluid dynamics, sorry), but what is that point? I'd guess it would be above idle somewhere. Combine that with the other important stuff that needs to warm up, and we arrive back at the original conclusion to not let your car sit and "warm up".

And wait a second. The world isn't flat? Consider my mind blown. :cheers:

At the end of the day we may be arguing about 2-3 minutes difference between your 30 seconds and my warm up.

The thing I learned from the article is that pressure does not always equate to lubrication.

It's not that it's going to necessarily hurt your car, but that it's just not needed with modern cars.

Anyway, hope the OP figures out the overheating/low coolant warning problem. Good luck.

I'm not sure we do agree at all.

Wear occurs at startup - 85% in a 'normal' engine's lifetime. But not because the oil isn't warm, because all the floating parts - crank, cam aren't floating and because the other metal parts experience metal-to-metal contact until oil flows to float and/or coat or 'film' the other parts. It is quite literally akin to bearing starvation for a few seconds on each cold start. Bearing starvation on a track can destroy a bearing in just one turn, so you can imagine the cumulative effect this can have over time - it has nothing to do with the temperature/viscosity of the oil, only the absence of it.

And while cold oil may be more viscous, the question is more viscous than what? That same oil a few hundred degrees warmer? How much lack of viscosity is necessary for the oil to flow? What is the W on multi-grade oil mean? - That is the viscosity (or resistance to flow) of the oil at a certain temp - for a W0 rated oil, that temperature is: - 22°F and it's resistance is 3250cP. Compare that to a 25W oil which is 6000cP @ +23°F and you see what a tremendous difference it makes to use a multi-grade oil. And, in a multi-grade, this is the base oil - the addition of polymers means that the oil 'thickens' (in terms of resistance) as it's temp rises, not the other way round.

The question you pose isn't àperpot. It isn't a question between these things at all. You either experience normal startup wear alone,... or you add to it the effects of inefficient combustion on your catalytic convertor and the adverse effects of reduced flow of coolant and oil to the engine - the first is unavoidable (unless you have an electric pre-luber), but the second is totally voluntary.

If you have cars with 200k on the original engines - congratulations! You fall into the group of about 75% of all people with cars built after 1994 - 200k is now the norm for modern engines which have been well maintained. That is not unusual at all these days.

Cheers!

Why would there be added wear
 

if, instead of sitting idling at 800-1200RPM, the engine and transmission were operated below 2500 RPM as you drive for the first few miles?

My Boxster now never goes out on cold days but when it did, it was a daily driver and took off slowly as soon as the seat belt was buckled which means maybe 15 seconds after start. The only time I ever idle to warm the cars I own are in snow, ice or fogged windows conditions where it is a matter of safety.

I agree, I believe most of the wear occurs within a few seconds of startup and without a preluber system it is unavoidable. It can be minimized with a low viscosity multi-grade synthetic oil, but not eliminated. I personally let my cars warm up and idle for several minutes if it is sub freezing. The colder it is the longer I let it warm up and idle. Under a cold start in those conditions the car's ECU sets the idle higher, usually close to 2,000 rpm for awhile to get the oil pumping and engine warmed up faster I assume. This may be all wrong and pehaps I'm making things worse for my engine and exhaust system, but it makes the most sense to me so I do it, plus it's no fun getting into a freezing cold car. In regards to let it idle or not, in the end it probably doesn't matter much either way, people have their preferences and there is no clear right or wrong answer. I do think some of the push to drive off right away comes from the "green" camp who hates car emmissions thus can't bear to see a car idling away doing nothing but polluting the air. I believe this line of thinking has influenced the mainstream and "car people" alike.

This sounds good in theory, but if you shift at 2,500 rpm then you are putting the engine in a very low rpm range essentially lugging the engine some which is a no no. The rpm difference between 1st and 2nd gear is about 2,000 rpm so shifting from 1st gear to 2nd gear at 2,500 rpm would drop the revs to aprox 500 rpm. Just playing the devil's advocate maybe, but it seems a lot of people are splitting hairs on this subject so I figured I'd throw that in there.

I agree that you shouldn't let the RPM drop below 800-1000 while driving off, but you're not really lugging the engine as long as the throttle opening is very small. Lugging is created by a large throttle opening, with the resultant high cylinder pressures, at low RPM.
Steve

If you're going easy on the throttle (as you should be during warm up), it is not lugging.

Shifting at 2,500/15 mph in 1st does not drop the revs to 500 rpm in 2nd. It drops them to around 1,500 in 2nd, and that's fine.

After reading your guys' posts and thinking on the subject a bit I'm in agreement with both of you.

A few days ago my friend had his new second hand BMW 325 sat on his drive, he was set to head back to uni (engine running) when he heard the doors lock while he was saying his good bye's.

We spent around 20 mins trying to break into it as he didn't have a spare key, in the end we phoned an auto lock smith who said he could guarantee to get in it and be there fast.

The lock smith turns up and starts messing with the door lock, we notice that the temp gauge was rising towards the red.

The lock smith kept going back and forth to his van to try a different tool.

Then the smell started, like hot brakes.

We were saying "Break the window, turn it off" but the auto guy was like (ive nearly got it) them an alarm sounded, like a low pitch buzzing which was definitely a bad sign.

I shouted "break the window!" but he still didn't. He was running around the car hoping that the auto locksmith would win out.

Then there was a cough, a splutter then the car stopped and a huge amount of steam came out from under the hood.

10 seconds later the auto locksmith managed to open the door by using some kind of inflatable pillow in the door corner which allowed him to poke a stick into the car and hit the window release button.

We now know for a fact that the head gasket has gone which is a £400 fix and we don't know what else may have been damaged.

It was horrible watching his new car go from "oh ****************, the doors just locked" to a dead car.

I will never leave my keys in the car and shut the door now. No idea why his doors all locked too which is another mystery.

Anim

If your friend had rammed some rags up the exhaust tail pipe, the back pressure would have stalled the engine. But I know what you mean - you tend to panic when things spiral downwards.....

We had a rather strange (err unusual) guy working for our company 3 or 4 years ago. He drove a small Suzuki 4 wheel drive thingie to / from work. He was always carrying things - things like like raincoats, lunch boxes, news papers, plastic bags, etc.
He left the Suzuki as usual and went into the office to start the day - when he re-appeared 8 hours later to go home, he found that he had forgotten to switch off the engine :eek: The poor car had been sat idling in the parking lot from 0700 hrs to 1600 hrs. He just shrugged his shoulder and drove home....
Mind you, he was the kind of guy who believed that the car was serviced each time you filled up with fuel!! And you don't need to change modern oils either!!
As I said, he was a little strange.

Its interesting you should mention the rags, we tried that for a few minutes but nothing happened so he stopped. Maybe we should have persevered with it.

I don't understand how that could happen to your friend because according to several here, it's not harmful to let the car sit and idle, unless of course they're incorrect.

Cheers!

Man what a horrible thing that would have been to go through! I suppose I would have tried to pinch off the fuel line somewhere but would have probably ended up catching the whole thing on fire. It is funny that the cars that no one cares about can idle for eight hours without an issue and the nice ones self destruct. It is the way of the world I guess.

so one car out of thousands which sit idle every day... and this is concrete evidence that idling is bad?

coming from NE ive left cars idling along with pretty much everybody I know for extended periods of time with no issue. I even left (by mistake) my car on all day while I went skiing... car still runs fine to this day.

I guess some cars can and others can't. You would have thought that a BMW would have some kind of over heating cut-off.

It's not that it's necessarily bad, it's just completely unnecessary, wasteful, and illegal in a lot of places.

The cars that overheat likely have cooling system issues that would have popped up somewhere down the line anyway. Any car with a properly functioning cooling system should have no problem keeping the car in spec at idle for a long period of time.

Really sucks about the BMW, but then again, they aren't exactly known for their quality cooling systems. Just the opposite, in fact... they have crap cooling systems that have a tendency to fail.

i guess that is my point right there... it isnt necessarily bad and a properly maintained car is fine. unecessary? have you had to get into a car in -30 degree weather? and illegal... never heard that but i dont doubt it.

-30? No, but -10 or so. In that case, I give it 20-30 seconds, and off I go. Warms up much faster that way. As for warming the interior, that's why they invented coats and gloves (and heated seats). In that kind of weather, the heat is warm within 3 or 4 minutes of driving.

That and people who live in places where -30 is commonplace typically have block heaters.

As far as it being illegal is concerned, it's not a law in too many places around here, but it damn well should be. Do you let your car idle at train crossings or in a stopped traffic jam? That's another waste. I prefer my gas to be wasted in the form of tire burning fun.

It is illegal in the UK it seems. Just googled it.

Edit: If on the public highway.

The UK has a law against EVERYTHING!

But my car is not sitting still it is rotating with the earth at 24,000 miles per hour!

I know, thats why we all sneak about at night. Its to risky to be caught doing anything in the day.

@ Anim,

Yea... must always be on the lookout for that proverbial Sheriff of Nottingham! LOL

Cheers!

never had a block heater... car always started up let it sit while i put my gloves and hat on and away I went. personally i like tire burning fun and well idling doesnt bother me at all i guess i just make up for all the people trying to save the planet. :cheers: