Mk2 Owners, Ever Noticed This..?

[RowMR2turbo]

I've owned three mk2 MR2's in over four years now and I've been meaning to ask this question for I'm yet to see it ever raised on TOC or IMOC but for some unknown reason only now do I decide to finally ask.

Ok, you jump in your car in the morning be it either a turbo or n/a and you drive off. Drive with the heater set to cold *Min* and allow the engine temperature gauge to raise to half way as per usual say after 5 - 10 minutes.

With the needle half way if you then turn the heater to from *Min* to *max* and switch the blowers on the needle on the temperature gauge drops very very quickly back down to cold even though the engine is hot!

Now I'm sure there's a perfectly logical explanation for it but I've noticed this on all of my MR2's so I'm sure its completely normal!!??

[Rikki]

I've owned three mk2 MR2's in over four years now and I've been meaning to ask this question for I'm yet to see it ever raised on TOC or IMOC but for some unknown reason only now do I decide to finally ask.

Ok, you jump in your car in the morning be it either a turbo or n/a and you drive off. Drive with the heater set to cold *Min* and allow the engine temperature gauge to raise to half way as per usual say after 5 - 10 minutes.

With the needle half way if you then turn the heater to from *Min* to *max* and switch the blowers on the needle on the temperature gauge drops very very quickly back down to cold even though the engine is hot!

Now I'm sure there's a perfectly logical explanation for it but I've noticed this on all of my MR2's so I'm sure its completely normal!!??

This allows the water/coolant circulating in the cooling system to pass through the "cold" heater matrix and with the fans blowing this air into the cabin lowers its temperature further.

This is why the temp gauge drops down, but soon rises up again.

R.

[Bibbs]

and the stock needle is rubbish .. by cranking the hearer on, the pumps kick in proper ..

[RowMR2turbo]

Aha, I see - cheers Rikki.

I'm suprised more owners haven't noticed this happen to be honest. I often rely on the tempertaure gauge in the moring to determine when not to drive the car hard, seeing the needle drop so quickly uneased me slightly. Having said that ubiking around with the heater control isn't going to have an effect on the oil temperature regardless!!

:D

[Bibbs]

the temp guage should NOT be used as a "boot it" guide ..

I've seen a proper guage plumbed in, and it just proves the guage is as good as the stock boost guage ..

and the oil takes so much longer to warm up ..

[alex_93gtuk]

Yes I second Bibbs' comments. I wait about 5 mins after the cars reached normal temp. You can feel the gearbox is still 'clicky' and stiff when cold. When the gearbox oil is up to a good temp the gearchanges get smoother and then my right foot action can commence

Alex

[Stu8]

I just keep my heater on "Auto" so cant say i've ever noticed that.

Mine seems to be excellent at holding it's temperature, even on the track after a few laps of abuse it doesn't rise.

[RowMR2turbo]

the temp guage should NOT be used as a "boot it" guide ..

I've seen a proper guage plumbed in, and it just proves the guage is as good as the stock boost guage ..

and the oil takes so much longer to warm up ..

Fair enough point, would I be right in thinking that the oil has reached full temperature in around 10 minutes of 2k-4k rpm driving during average weather conditions then?

Or longer still?

[Bibbs]

I was told (and this is 2nd hand to me) that 10-15 mins is better ..

[Stu8]

after 10mins it should be OK then

I set my turbo timer on 10min startup before I drive it, and my oil gauge always read's that it's up to temp.

[Bibbs]

But what can I say .. I boot it out the drive ;)

[Stu8]

But what can I say .. I boot it out the drive ;)

tut tut :D

[Fizz]

my needle has never dropped or raised one at full temp...

and i use the fans at max heat etc...??

[Stu8]

I often drop one....

[Bibbs]

I often raise one

[Jesus]

Crank the heat up and fan on full on a hot day and open your windows... cools the water down a little and makes the car run better in the heat.

I have an oil temp gauge fitted. I wait until that's up to good temperature before squeezing the loud pedal. If the oils up to temp... the water certainly is.

[Fitz]

Is that something specific to the MR2...drive with heater on cold until water warms up? My instant reaction when I get in a cold car is heater on full.

[Rikki]

Is that something specific to the MR2...drive with heater on cold until water warms up? My instant reaction when I get in a cold car is heater on full.

You'll just get cold air LOL

[Fitz]

yeah but doesn't take very long to warm up

[JappyBeast]

I just keep my heater on "Auto" so cant say i've ever noticed that.

Mine seems to be excellent at holding it's temperature, even on the track after a few laps of abuse it doesn't rise.

Auto is climate control, hope you keep your windows up!

I hardly ever have the temp on low.. its either on hot or off alltogether.

Think my AirCon is <I thought I could get past the swearing filter - what a sad muppet I am eh?>ed as the revs no longer rise when I put it on!

What is wrong?

[ricomr2]

Think my AirCon is <I thought I could get past the swearing filter - what a sad muppet I am eh?>ed as the revs no longer rise when I put it on!

What is wrong?

Blown a fuse maybe?

Or it might need recharged but i dont think that would stop the revs rising when you switch it on

[JappyBeast]

Where is the fuse?

[ricomr2]

Dunno mate, dont even know if it has one....

Just check all the fuse boxes

[Stu8]

It could be the A/C Amplifier or the Vacuum Switching Valve?

[JappyBeast]

It could be the A/C Amplifier or the Vacuum Switching Valve?

In laymans terms?

Will it cost more than £1 to put right?