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Blue Coolant temperature light, how long before it clears

71K views 59 replies 34 participants last post by  Speedy Scholten 
#1 ·
Hello,

So we bought the 2010 Forester for my wife. We owned the car a little less than a month and we always see the blue coolant/temperature light when we start the car in the cold morning. It takes about 30 seconds (or sometime longer) before it clears itself. According to the manual, it is okay to be blue and I have read that it is to indicate the engine is not warmed up yet.

My wife refuses to move the car until the blue light disappears. (Any advice?)

We are wondering how long it takes for the blue light to clear for other 2009/2010 forester owners. Can you also indicate whether your forester is in a cold weather or warm weather environment. That would be helpful too.
 
#2 ·
Welcome to the Forum, it takes 3 to 4 min before mine goes out now that winters here.. And your wifes smart to let it warm up before driving. It could possibly prevent costly head gasket repairs later in the cars life.
 
#20 ·
... your wifes smart to let it warm up before driving. It could possibly prevent costly head gasket repairs later in the cars life.
Others of us do not believe that gentle driving during warm up has any effect on the head gaskets.

Some car manufacturers discourage warming up by idling. The Owners Manual of my Toyota says:
Engine should be warmed up by driving,
not in idle. For warming up drive with
smoothly turning engine until engine coolant
temperature is within normal range.
The general advice is to not warm up by idling:
Myth #1: The engine should be warmed up before driving. Reality: Idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is to drive the vehicle. With today's modern engines, you need no more than 30 seconds of idling on winter days before driving away.
Idling Your Car
The problem is, letting your car sit and idle is the slowest way to bring it up to operating temperature because it’s generally sitting in your drive at just above idle speed. And this method to warm up also invites other problems... Even when it’s 10 degrees F outside, start your car, let it run for 30 to 60 seconds to get all the fluids moving, then drive off gently. Your engine will warm up faster, your exhaust system will get up to temperature faster so the catalytic converter can do its thing, and you’ll use less fuel.
Should I let my car warm up each morning?
 
#3 ·
I belive that regardless of the light it's healthy to drive with no hard driving until the engine got some heat. If it takes around 30sec before it's gone I say let it stay stay parked until the light is gone but I can't see why you should need to, It's just better for the car I belive. Frozen oil is bad for a running engine anyway.

Hope someone else can chime in on this.
Not so helpful for your blue light.
 
#4 · (Edited)
My recollection is that my car's blue temp light turns off when the coolant temp reaches ~122F (~50C). How long the engine takes to reach that temp will depend on ambient temp, initial loads, etc. It'll be one thing in the summer, and another in the winter. I've never let it just sit and idle long enough to extinguish the light.

(Any advice?)
Personally, based on 40 years driving experience, I think it's OK to gently drive off if the indicator is blue but the engine has idled for five- or ten seconds or so. Just no hard acceleration or high-speed driving until the blue light is off.

HTH,
Jim / crewzer
 
#5 ·
Ask her if in her last car she refused to move the car til the temperature gauge needle (if it had one) moved into the "normal" zone, because that's what she's doing right now.

It's no different than any other car, you don't hammer on it til it's up to temperature. In the winter I will run my car for a minute or two before I gently drive it til it's fully warmed up, but I'm not gonna sit there until it's fully warmed up, that'd take like 7 minutes or something in my Forester.
 
#8 ·
I was about to echo everyone else's sentiments here, that it's okay to drive off with a light foot before the blue light goes out (cuz I sure do)...but decided to check the owner's manual first. Nine again, my 09 2.5X has the same engine as your Forester. The manual's section regarding the coolant temp light says "Illumination in BLUE indicates insufficient warming up of the engine." (pp 3-13) The section on starting the vehicle states "The fuel injection system automatically lowers the idle speed as the engine warms up. While the engine is warming up, make sure that the selector lever is at the P or N position and that the parking brake is applied." (pp7-9).
So, it would seem that Subaru agrees w/your wife...that it's best to wait until the blue light goes out before driving off. And that really surprises me....:confused:
Steve
09 2.5X AT
 
#9 ·
Curious... if the later Foresters had a coolant temperature gauge, would you wait until the gauge pointer moved upward before driving off? I would guess not. :wink:

On the newer vehicles, the ECM will compensate for the operating temperature by increasing the idle speed, fuel mixture, etc. A wise person would understand diving gently while the engine is getting up to the normal operating temperature will ensure a long lasting engine. IMO, unless it's extremely cold, it's better to start & gently drive off.

Just my .02 cents worth. :smile:

Bobby...

My MODding Journal
 
#10 ·
My '10 Premium takes awhile for the blue light to go out. In fact, I'm not sure I've actually let it sit and idle until the light went out by itself...maybe once or twice, but it took awhile. Strangely enough, if I let it warm up for about 30 seconds or a minute, then gently drive off, the light goes out in another 10 seconds of driving. Almost like a short bit of driving helps her warm up faster?
It's funny though, how a blue light telling you "I'm not warm yet" is more effective than the standard temperature gauge at convincing us to let it warm up a bit longer...but it's true. I think with the standard gauges, we all could "assume" the car had warmed up enough without the needle moving.

So...basically, I let her warm up for a minute, then just drive very gently until the light goes out.
 
#11 ·
Blue Coolant light

I always try to wait for the light to go out on my wife's 2009. Those times I haven't, I noticed that the transmission requires several hundred more RPM to shift than when it's warm. Whether that's the computer or the AT I can't say, but it does remind me that it's not only the engine that needs warming up.
 
#12 ·
Thanks for everyone's reply to my questions. This forum has been very helpful.


Jared_N really clarified it for me.
I notice that my Venza (our other car) does have the temperature gauge and it does take a quick moment to reach the middle or the normal temperature.

The Forester does not have the temperature gauge, but rather have this indicator, i.e. the blue light disappears when the temp reaches normal.
 
#21 ·
...The Forester does not have the temperature gauge, but rather have this indicator, i.e. the blue light disappears when the temp reaches normal.
The 2008 and older Foresters have a needle but it does not show temperature. Like the 2009 lights, the 2008 "gauge" is merely an indicator. The needle rises to a fixed position at 150F, and stays there while the temperature continues to rise, all the way to 210F. As long as the temperature is in the normal range, the needle, like the lights, is inactive.

The indicator needle, like the indicator lights, prevents needless worry about variations and fluctuations in temperature.
 
#14 ·
The blue light most definitely does not signify "normal"

My 09 OBXT has a gauge AND a blue indicator light. The light goes off when the gauge reads about 1/4 to normal.

I usually get in the car, start it, and put on my seatbelt before driving off. I don't think it's ever seen more than 2500 revs before being completely normal though.
 
#16 ·
Intresting.. I had never read that part of the book.. Now reading it I see what you guys mean... It does however say the AT will stay in lower gears to bring the engine revs up to help warm the engine faster.. But all in all its really not well stated what to do..

But our 01 Forester book says.. We recommend that you drive moderately until the pointer of the temperature gage reaches near the middle of the range.. Engine operation is optimum with the engine coolant at this temperature range and high revving operaration when the engine is not warmed up enough should be avoided..

The book on the VW says start engine.. When the oil light goes out start to drive keeping the engine at lower speeds until its warm.. Excess idle time causes excess engine wear and waste fuel..

The book on the Mercedes says about the same thing..

I have always started the car and when the oil pressure is up I have driven off keeping the revs down.. I have never had any engine problems and have driven some of our cars for up to 750,000 miles.. So guess I will stick with what I know works.. And with the much thinner oils we use now, I think it will be less of a problem..

I bet over the 10 to 15 years most of us own the cars idle time would use enough gas to drive thousands of miles if you let it set until the light goes out all the time.. However I do think every one should do what ever they think is right..

Snowdance

Flickr: snowdance38's Photostream
 
#17 ·
We are wondering how long it takes for the blue light to clear for other 2009/2010 forester owners. Can you also indicate whether your forester is in a cold weather or warm weather environment. That would be helpful too.
I timed my 09 car's "blue temp light off" cycle this morning before running a few errands: just over two minutes from 29F ambient to blue light off (122F / 50C coolant temp per OBDII > iPod Touch w/ Rev2) with the seat warmers on LOW, the windshield defroster on, and the blower motor speed set to "2".

HTH,
Jim / crewzer
 
#19 ·
Our salesman said the rpm would stay a bit higher until the light went off but that we could drive off with the light still on as long as we were driving reasonably, ie not suddendly on the highway doing 60.

I'm in Montreal Canada and with the temperature below -10C we let the car warm up for a minute or two and then take off slowly, the light is usually off by about two or three blocks from home.
 
#24 ·
The other day, I've got in my Nissan, started it up, waited about 30 seconds (my normal waiting period, while I put on my seat belt and adjust the radio). Then I've pulled away from my driveway. We have a 90' left turn at the end of the street that doesn't see sunlight often so it's always covered in snow/ice during winter. I got up to about 30, yanked the e-brake, and FWD drifted through the turn. As I was flying sideways, spinning tires and kicking up snow, I've remembered of this thread :biggrin: OOPS!!! :rock: Then again, I don't have a little blue light telling me what to do either :cool:
 
#25 ·
That little light is a great reminder that the engine is cold. But I wish I had a temp guage too.
I try to not exceed 2500 rpm while it's on, and find that you can drive reasonably at up to 60mph or so doing that, regardless of the outdoor temp. I guess this is a bit more important for turbo engines, which mine is. It's also a good indicator of when to kick up the heater fan and not get a cold north wind from your heater.
 
#27 ·
Nope....Not the Basic or Premium. Just the Limited. Mine's a Premium. Normally I really don't like climate control since I think that fan noise on automatic is annoying (had it on a Nissan, Porsche, + Infiniti), but I have to say that with these lightweight small Subaru engines, the temps are not very stable and I wish I had a little computer helping to keep the cabin temp level. I make a few more manual adjustments than I want to to keep it comfortable. Oh well, it won't be winter for ever....right??
 
#28 ·
Just got 2011 Forester 2.5x w/ the Canadian version of the Touring Package in January. Love it. Although I do wish that the Canadian Touring was the same as the American Touring (got a lot less at a higher price).

From what I see, the blue light is just a reminder that the engine is not warm up yet and should not push it too hard (not go into the sport / manual mode as the RPM will be too high). Think of it as a daily break-in period for a few minutes.

Anyone tried to warm up the car with a block heater? I had it on my 8 yrs old Vibe and it did help with the lowering the idling speed during cold start.
 
#30 ·
I am also from the "drive gently immediately after starting" club. If you wait until it warms up, you are getting exactly zero MPG at a time when the fuel injection is running a rich mixture. Especially today, you might as well put those those hydrocarbons to good use by moving the car.
 
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