Blue Engine Coolant Light

[CX-SV]

Basically, there are 4 temperature indications.

1. BLUE temperature light means that your engine is below normal operating temperature,
2. NO temperature light means things are normal,
3. FLASHING RED temperature light means that engine is above operating temperature and you should pull over soon,
4. SOLID RED LIGHT means that you are overheated, and to pull over immediately.

^ This is why Mazda's blue/red/flashing red system is better than a questionably accurate temp gauge that gets ignored by many drivers.

Also because this engine has DI and a longer warmup period, the blue light is a helpful reminder to drive moderately until blue light goes out.

I have another car with DI (and a longish warmup period) and a normal temp gauge and it's more tedious to monitor when the engine is warmed up for hard driving.

 

[devo1255]

^ This is why Mazda's blue/red/flashing red system is better than a questionably accurate temp gauge that gets ignored by many drivers.

Not sure I agree with it being better. The blue/red/flashing red system doesn't tell you the rate at which the engine is warming up or cooling down. Just knowing the temp of the coolant is one part of the diagnosis ... if you know how quickly or slowly the temp is changing I believe you can proactively determine when you should stop driving or when things don't seem right with the system.

 

[CX-SV]

. Just knowing the temp of the coolant is one part of the diagnosis ... if you know how quickly or slowly the temp is changing I believe you can proactively determine when you should stop driving or when things don't seem right with the system.

Exactly the point of the Red FLASHING light (not the Solid Red light), it's more likely to get drivers attention so you can proactively determine when you should stop driving..

 

[ZDA3]

I had been curious about this as well. I have a 2015 Mazda3. I'm curious if I can drive my car immediately while the blue engine coolant is still blue? My old car's version of this was a C (meaning cold) and H (meaning hot). I'm assuming the blue engine coolant light means because the engine is still cold. There's a popular belief that I must wait at least 1 minute before I drive my car yet this information is really no where to be found in my manual. Must be a myth? So the blue light just means the engine is cold but I can still drive my car ASAP, right?

Hey...

When i start my car after not using it for a day, the blue engine coolant light is always on. It goes away after i start driving a bit and the engine warms up, but i was wondering if everyone else was experiencing the same thing?

Also, when u start the engine, the engine is pretty loud, although it does get quieter after about 20 seconds,

Anyone else experience these two things? Just wondering if this is normal

 

[GP 2004]

When I first start my car, the blue light comes on and I then connect my seat belt, turn on the seat heaters if needed, adjust the radio, check my mirrors to see all is clear. This takes maybe 30 - 45 seconds before I put the car in gear. I drive with the blue temperature light on, but I drive sedately and do not 'rev' the engine much until the light goes out.

 

[yrwei52]

^ This is why Mazda's blue/red/flashing red system is better than a questionably accurate temp gauge that gets ignored by many drivers.

But cars with coolant temperature gauge also have additional flashing or solid red high coolant temperature warning light! Hence it definitely a better way to tell the driver with additional info by a gauge for coolant temperature!

When I first start my car, the blue light comes on and I then connect my seat belt, turn on the seat heaters if needed, adjust the radio, check my mirrors to see all is clear. This takes maybe 30 - 45 seconds before I put the car in gear. I drive with the blue temperature light on, but I drive sedately and do not 'rev' the engine much until the light goes out.

This is exactly the way I told my wife to drive-off her CX-5 in the morning! In the colder days I remind her to do these steps slower so that it takes a bit longer time to warm up the engine.

Although the owner's manual doesn't say anything about whether you should drive the CX-5 with blue coolant temperature light on, but in Smart Start Guide it does say the vehicle can be driven with the light on or off.

This blue coolant temperature light is the most asked question I've heard from friends with CX-5's.

 

[craigo]

IIRC, the manual asks to drive it gently before its up to temp. Cool engine = thicker oil. Transmission needs a little time to warm up to temp as well. But if you have to accelerate quickly to avoid an accident, dont worry about it.

 

[CX-5um]

I usually drive under 10 mph and wait for the blue light to disappear. Once its gone I redline it...just kidding.

 

[ColtX-5]

*

The blue light indicate the Engine is still cool......When it gets up to temperature it goes out. Overheat will get the red indicator lit. (this is all in lieu of a temp gauge)

Start up noise is pretty normal on Emissions controlled direct injection engines. Perfectly normal

Hooked up my Scangauge this AM. The blue light goes off at 132F. It took 6 more miles of gentle suburban driving to get to 181F (fully warmed up).

 

[ZDA3]

I noticed the blue light disappears faster when driving the car rather than just sitting still. Not sure if driving the car warms up the engine faster. I'd assume it shouldn't matter if driving with the blue light on considering coolants/antifreeze work in both cold and hot weather.

 

[fdew]

I agree that a temp gauge is a good thing. I wanted one because I pull a trailer on the highway. I went to see a trend, not a red light. I went with Scangauge E
http://www.mazdas247.com/forum/showthread.php?123845939-How-do-I-remove-the-Front-power-plug-pannel

I hope future cars take a cue from Tesla and let you chose what is shown on the instrument panel. There instrument panel is a video screen and you can put what you want on it

 

[halfast3]

I usually drive under 10 mph and wait for the blue light to disappear. Once its gone I redline it...just kidding.

Hope you don't live across from the interstate on-ramp (whistle)

 

[MikeM.]

I noticed the blue light disappears faster when driving the car rather than just sitting still. Not sure if driving the car warms up the engine faster.

Your engine warms up faster when you drive it because it's burning more fuel while driving than at idle.

 

[craigo]

But cars with coolant temperature gauge also have additional flashing or solid red high coolant temperature warning light! Hence it definitely a better way to tell the driver with additional info by a gauge for coolant temperature!

This is exactly the way I told my wife to drive-off her CX-5 in the morning! In the colder days I remind her to do these steps slower so that it takes a bit longer time to warm up the engine.

Although the owner's manual doesn't say anything about whether you should drive the CX-5 with blue coolant temperature light on, but in Smart Start Guide it does say the vehicle can be driven with the light on or off.

This blue coolant temperature light is the most asked question I've heard from friends with CX-5's.

Some people also mistakenly think its a low coolant warning. Meanwhile, the useful parts of the manual can be read in about 15 minutes...

 

[russiankid]

*


Hooked up my Scangauge this AM. The blue light goes off at 132F. It took 6 more miles of gentle suburban driving to get to 181F (fully warmed up).

This is important. Just because the light goes out it doesn't mean the car is fully warmed up, it takes a bit more time for the coolant temps to get to normal operating range. However, just because the coolant is up to temp, it does not mean the oil is up to temp as it takes longer for the oil to heat up than water. Just keep that in mind next time you notice the blue light goes off and a CRV wants to race you (eekdance)

 

[inlinev]

This is important. Just because the light goes out it doesn't mean the car is fully warmed up, it takes a bit more time for the coolant temps to get to normal operating range. However, just because the coolant is up to temp, it does not mean the oil is up to temp as it takes longer for the oil to heat up than water. Just keep that in mind next time you notice the blue light goes off and a CRV wants to race you (eekdance)

Wouldn't the oil get up to temp first since it literally coats the cylinders, the direct source of heat.

 

[GAXIBM]

A larger volume of oil is sitting in the pan than is in contact with warm engine parts so it has to circulate to heat up. A lot of the engine parts are not that hot.

 

[russiankid]

Wouldn't the oil get up to temp first since it literally coats the cylinders, the direct source of heat.

Like GAXIBM said, a large portion of the oil sits in the oil pan. Drive the car until the coolant temp light goes out, pop the hood and feel around. I bet the upper rad hose is barely hot, lower is probably stone cold, and oil pan is maybe luke warm.

 

[MikeM.]

A larger volume of oil is sitting in the pan than is in contact with warm engine parts so it has to circulate to heat up. A lot of the engine parts are not that hot.

The CX-5 squirts oil into the underside of the pistons to cool them. Pistons (along with the exhaust system) are the first things to get hot.

Excellent thermal management and attention to detail in this area is one of the significant technologies that sets Skyactiv engines apart from the pack. The coolant temperature rise of a cold Skyactiv engine is actually slowed considerably because the initial coolant warmth is used to warm the transmission fluid via heat exchanger. Cold transmission oil not only accelerates wear of the transmission but it is also inefficient. Using the initial coolant heat to warm the transmission slows down the initial rise in coolant temperature significantly. The same heat exchanger is also used as a transmission cooler when the transmission is working hard in the heat. So the radiator doubles as a transmission cooler - smart engineering.

What really determines when an engine is warm enough to be run hard is the temperature of the metal in the block (and this is more closely related to the temperature of the coolant than the oil). I say this because the pistons come up to reasonable temperature very quickly being small and light and in direct contact with the combustion process. The main concern is not how warm the oil is (0W-20 lubricates just fine at zero degrees) but whether the metal parts have expanded enough to take up the slop designed to accommodate this expansion. This is 80% accomplished in the first minute or two of driving but it's a good practice to give it 10 minutes to reach 99% equilibrium before really stomping on it hard.

 

[russiankid]

The CX-5 squirts oil into the underside of the pistons to cool them. Pistons (along with the exhaust system) are the first things to get hot.

Excellent thermal management and attention to detail in this area is one of the significant technologies that sets Skyactiv engines apart from the pack. The coolant temperature rise of a cold Skyactiv engine is actually slowed considerably because the initial coolant warmth is used to warm the transmission fluid via heat exchanger. Cold transmission oil not only accelerates wear of the transmission but it is also inefficient. Using the initial coolant heat to warm the transmission slows down the initial rise in coolant temperature significantly. The same heat exchanger is also used as a transmission cooler when the transmission is working hard in the heat. So the radiator doubles as a transmission cooler - smart engineering.

What really determines when an engine is warm enough to be run hard is the temperature of the metal in the block (and this is more closely related to the temperature of the coolant than the oil). I say this because the pistons come up to reasonable temperature very quickly being small and light and in direct contact with the combustion process. The main concern is not how warm the oil is (0W-20 lubricates just fine at zero degrees) but whether the metal parts have expanded enough to take up the slop designed to accommodate this expansion. This is 80% accomplished in the first minute or two of driving but it's a good practice to give it 10 minutes to reach 99% equilibrium before really stomping on it hard.

In most cars and trucks, the radiator has a built in transmission cooler that has separate lines running from the transmission to cool it off. The CX-5 just has a different/smarter system as you mentioned to warm up the ATF.

As for operating temperatures, I do agree that the temperature of the metal plays a very important role, but I believe the oil does as well in order to properly lubricate/protect the components.