coolant very hot

coolant very hot

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Discussion

dba7108

Original Poster:

471 posts

168 months

Monday 23rd March 2015
quotequote all
i thought the coolant was very hot in my 645 to the point that its actually boiling and if i take the top off it isnt very nice to put your finger in there! So i changed the coolant - opened the rad and let it drain but didnt drain the engine block. Filled it back up today with 5 litres of concentrate then i was going to put 5 litres of distilled water in but i could only fit about 1 litre in. started engine and coolant still gets very hot. I spoke to a BMW specialist and they said these engines do get very hot (i had a 1.6 ford before so different type of engine i guess) but i thought before how hot the bmw ran.
Also does the electric pump procedure work on these cars where you hold the accelerator down as I couldnt get it to work.

Simes205

4,536 posts

228 months

Monday 23rd March 2015
quotequote all
Is this a serious post?
Do you expect it to be cool??

edo

16,699 posts

265 months

Monday 23rd March 2015
quotequote all

y2blade

56,091 posts

215 months

Monday 23rd March 2015
quotequote all
"Cool"ant

8Tech

2,136 posts

198 months

Monday 23rd March 2015
quotequote all
Classic case for the requirement of a non opening bonnet for certain owners?

bearman68

4,652 posts

132 months

Monday 23rd March 2015
quotequote all
Give the OP a break - it's complicated.
BMW generally run at over 100 deg C coolant temperature to improve fuel efficiency. When you are booting it, or during some other conditions, the coolant temp will drop below 100 deg, to prevent the engine overheating, but still 95 ish at a guess.
The reason the coolant doesn't boil is that is is under pressure. When you remove the cap, it isn't, and boils. Not good.
The temperature gauge shows a constant normal running temp, even if the coolant temperature is being varied under the control of the ECU. (Electric thermostat). It does this to stop panic on the drivers behalf - so the coolant gauge is actually quite a complex unit, and it shows idealised temperature, not actual.
So the coolant temp will 'feel' really hot all the time - this is normal. Look at the gauge, if it's running hot, it's hotter than it should be.
As a tip, the heaters should also be blowing hot air when asked as well. If they don't do this, you may have an air lock, and this is serious.

And breathe.......

Kawasicki

13,078 posts

235 months

Monday 23rd March 2015
quotequote all
Why don't bmw call it hotant? That would help avoid confusion.

To clarify, if you see the engine temperature pointer getting hot, you need to drive it harder, or check the coolant. Make sure you use an oily rag though.

dba7108

Original Poster:

471 posts

168 months

Monday 23rd March 2015
quotequote all
bearman - thanks

As i was used to the Focus before which when opened the coolant was pretty "cool", this 645 alarmed me at the temp the coolant was at. All the pipes from the tank are really hot to the touch - something that wasnt on the Focus. I know they are completely different cars and the bmw engine is more than twice the capacity.
There is no coolant temp needle as well which is annoying.

Simes205

4,536 posts

228 months

Monday 23rd March 2015
quotequote all
Don't take the lid off the rad/ expansion tank after a run, it is hot!
It is also pressurised and will scold you as it tries to escape.
Only top it up when cold.

Sardonicus

18,957 posts

221 months

Monday 23rd March 2015
quotequote all
Your Focus was not at operating temp because if it was you would not be able to put your finger in the exp bottle either 90+ degrees.

helix402

7,858 posts

182 months

Monday 23rd March 2015
quotequote all


i thought the coolant was very hot in my 645 to the point that its actually boiling and if i take the top off it isnt very nice to put your finger in there

Please don't put your finger in your coolant in the expansion tank to check how hot it is. Serious death or injury may result. There is a hidden menu on the instrument cluster if you would like to know your coolant temp, or diagnosis software or handheld unit.

Collectingbrass

2,207 posts

195 months

Tuesday 24th March 2015
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Step 1, get a Bluetooth odb reader and link it to the torque app on your phone. This will tell you the actual coolant temp the ECU is reading.

Step 2, get the cooling system checked over by a competent mechanic

anonymous-user

54 months

Tuesday 24th March 2015
quotequote all
Simes205 said:
Don't take the lid off the rad/ expansion tank after a run, it is hot!
It is also pressurised and will scold you as it tries to escape.
Only top it up when cold.
I think you would deserve a good telling off, if you took the lid off.

Anyone else wondering how some people manage to feed themselves?

TrollFinder

108 posts

171 months

Wednesday 25th March 2015
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I can confirm (on my E46 330d), using Torque and a bluetooth adapter, coolant temp when the gauge is halfway, is between 73 and 93C.

Triumph Man

8,687 posts

168 months

Thursday 26th March 2015
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Don't put your finger where you wouldn't put your penis. You wouldn't put your penis in the header tank would you OP?

philmots

4,631 posts

260 months

Friday 27th March 2015
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As one poster said.. They run very hot.

It's the same as my 550i, under light loads they run at 105 degs for effiency.

This can drop as low as 80 in very hard driving.

They also produce fault codes if coolant is out of range so is assume it's fine.

528Sport

1,431 posts

234 months

Friday 27th March 2015
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Was for focus petrol or diesel?

Diesels tend to run cooler.

do a google search and see if there are any hidden menus on your instrument cluster, sometimes you can get the cars to show engine core temp.

my old e39 528 was running at 110degrees far too hot, i changed the rad (it was bowed at the bottom) and for good measure the thermostat. after that it ran at 92-95 max..

Please also note that coolant isn't very good at cooling.... Coolant or antifreeze as its known does 2 things. Stops water freezing and raises its boiling point to say 120 degrees so it doesn't boil over. Thats why you have a 50/50 mix. In theory a 60/40 mix would be better but the freezing point becomes higher .
Water is the better of the 2 components to get rid of heat.
you said you put a few letters of coolant in and then 1 ltr of water.... Not good. drain the system and make sure you get the mix done properly...


528Sport

1,431 posts

234 months

Friday 27th March 2015
quotequote all
Was for focus petrol or diesel?

Diesels tend to run cooler.

do a google search and see if there are any hidden menus on your instrument cluster, sometimes you can get the cars to show engine core temp.

my old e39 528 was running at 110degrees far too hot, i changed the rad (it was bowed at the bottom) and for good measure the thermostat. after that it ran at 92-95 max..

Please also note that coolant isn't very good at cooling.... Coolant or antifreeze as its known does 2 things. Stops water freezing and raises its boiling point to say 120 degrees so it doesn't boil over. Thats why you have a 50/50 mix. In theory a 60/40 mix would be better but the freezing point becomes higher .
Water is the better of the 2 components to get rid of heat.
you said you put a few letters of coolant in and then 1 ltr of water.... Not good. drain the system and make sure you get the mix done properly...