Engine Overheating

[TW]Fox · 29 Jul 2008 at 18:08

mrk said:
Na can't be high obc only because my old 318 saloon did it hence how I know Drove to stoke and when engine was turned off the oil light glowed yellow.

Somewhat unsuprisingly, a yellow oil light after switchoff means your oil level is at the minimum mark NOT your coolant.

mrk · 29 Jul 2008 at 18:11

Aww snap, you're right I got it the wrong way round, it was the oil light that is dual coloured (top one)

The coolant light is the one with the swirly rings along the top of the symbol which came on orange. Both must have come on hence the confusion.

Mystery solved I suppose

Rich1988 · 29 Jul 2008 at 19:21

[TW]Fox;12179830 said:
You should be regularly checking your coolant levels anyway.

I have to admit I really agree with fox, before pretty much every journey i check my coolant and oil and brake fluid levels, they never go down but it only takes 30 seconds and can potentially save the car.

Clarkey · 29 Jul 2008 at 19:38

every journey? That would become incredibly tedious if you did more than 1 journey a week :/

West · 29 Jul 2008 at 20:50

I don't think it's OTT either, considering I do 40 Miles a day, in this weather it's worth checking every few days, esp with Mini's record of fantastic cooling systems..

The same can be said for anyone who racks up the miles on their daily commute

Berger · 29 Jul 2008 at 21:16

West said:
I don't think it's OTT either, considering I do 40 Miles a day, in this weather it's worth checking every few days, esp with Mini's record of fantastic cooling systems..

The same can be said for anyone who racks up the miles on their daily commute

Cant remember when i last looked under the bonnet of my work van, it just works and gets serviced when required and that does at least 1k a week. Check the tyres every day but coolant not that often really, when i top up screenwash so couple of weeks probably but its never needed any.

Check my coupe every other day as its a K series and im pretty certain at some point it is going to grenade.

Fr0dders · 29 Jul 2008 at 23:41

right, checked the coolant level. It is in fact a complete pain to check, and they've devised the most hard to read container you can imagine. But ive managed to establish that allthough its not on the max mark, its certainly well above minimum and probably somewhere nicely inbetween the two.

Interesting thing though, the owners manual says the coolant is to prevent damage due to frost and for preventing rust. Nothing about it being essential for keeping the car cool in the summer.

But anyway, im guessing the only other thing it can be, seen as the temp gauage keeps fluctuating between max and min is an electrical fault with the temp sensor ?

[TW]Fox · 30 Jul 2008 at 00:56

MrLOL said:
Interesting thing though, the owners manual says the coolant is to prevent damage due to frost and for preventing rust. Nothing about it being essential for keeping the car cool in the summer.

You are joking right? The coolant exists SOLELY to cool the engine. You have a watercooled engine - the coolant is the water which circulates and cools the engine. It's absolutely essential.

What you've read is that the antifreeze contained WITHIN the coolant is only there to prevent rust and stop it freezing. Which is true - in an ideal world water would work fine, but we dont live in an ideal world so water on its own causes rust, can freeze etc hence coolant is a mix.

Fr0dders · 30 Jul 2008 at 11:21

i'm not sure whats going on here

The water that runs through the radiator and engine cooling the system surely needs to contain litres and litres of the stuff ? but the clear plastic box marked as "coolant" in the manual is like half a litre at most.

Somebody said that a coolant flush and re-fill can be like 10 litres. So maybe the box marked "coolant" in the manual, is in fact just an antifreeze reservoir or something ?

Told you the manual wasnt clear !

stigggeh · 30 Jul 2008 at 11:39

antifreeze is summer coolant too, when ever i have bought antifreeze its said and summer coolant in smaller letters.

Your hand book sould give you a % of coolant to water ratio, I dont think it matters too much to be exact i think its usually around 40% coolant 60% water ?.

gurusan · 30 Jul 2008 at 11:46

MrLOL said:
i'm not sure whats going on here

The water that runs through the radiator and engine cooling the system surely needs to contain litres and litres of the stuff ? but the clear plastic box marked as "coolant" in the manual is like half a litre at most.

Somebody said that a coolant flush and re-fill can be like 10 litres. So maybe the box marked "coolant" in the manual, is in fact just an antifreeze reservoir or something ?

Told you the manual wasnt clear !

If you didn't buy premixed coolant then you need to put in distilled water along with the coolant you bought. On my civic i usually did 80/20 water/coolant but I think most poeple do around 60/40.

It's the exact same deal as with a watercooled computer really. Unless you bought premixed Feser One then you need to mix up your own with distilled water. this isn't very hard

[TW]Fox · 30 Jul 2008 at 12:09

MrLOL said:
i'm not sure whats going on here

The water that runs through the radiator and engine cooling the system surely needs to contain litres and litres of the stuff ? but the clear plastic box marked as "coolant" in the manual is like half a litre at most.

Somebody said that a coolant flush and re-fill can be like 10 litres. So maybe the box marked "coolant" in the manual, is in fact just an antifreeze reservoir or something ?

The tank is the expansion tank - it is connected to the rest of the system and contains many litres.

-westy- · 30 Jul 2008 at 12:35

[TW]Fox;12184867 said:
The tank is the expansion tank - it is connected to the rest of the system and contains many litres.

I was going to expand on this (see what I did there

) but thats probably the best explanation I could come up with

Fr0dders · 30 Jul 2008 at 16:57

[TW]Fox;12184867 said:
The tank is the expansion tank - it is connected to the rest of the system and contains many litres.

right, so the fact i can see its got fluid in, and appears to be somewhere just below the max line means it is in fact full of coolant ?

anyway ive done some researching, and it seems the likely culprit is a faulty coolant temp sensor. Seems quite common.

It fits with the behaviour of the guage as well, i never see it rise to 3 then 4 bars, it just suddenly shoots from 2 bars to full, then back to 2 bars again. When it hits full, the 2nd speed of the fan kicks in and the fan goes into overdrive, the temp sensor then reads normal and the fan goes back to slow speed again.

So the thermostat is fine, but looks to be a faulty temp sensor. Assuming the garage dont try and fob me off with leaking head gaskets and skimming the head etc.. it should be just a £10 + fitting job.

[TW]Fox · 30 Jul 2008 at 23:35

Yup, if the level in the header tank is only a tad below Max, there is plenty of coolant in the system.

That doesn't mean the system is perfectly operational though - could be a faulty waterpump?

Overlag · 31 Jul 2008 at 00:14

merlin said:
Meantime, back in the real world.....

how hard is to to check:
oil
coolent
tyre pressures x4 (plus spare if u have one)

weekly/monthly? each takes less than a minute ffs.

that takes a lot less time then the car dying on the way to work and wasting a whole day getting it recoverd, then weeks getting it repaired.... Thats REALWORLD btw.

real · 31 Jul 2008 at 00:52

Woops. I forgot about the antifreeze helping to prevent the rust. I've been topping up the coolant with normal tap for the past 10 or so months.

Anyone reckon it'll have done much damage?

If there are a couple litres in the system then it should just be extremely diluted. Hopefully no rust will have formed.

Clarkey · 31 Jul 2008 at 00:55

you will know rust has formed when your coolant goes a nice brown/orange colour.

real · 31 Jul 2008 at 01:13

Havent noticed a rust colour change. Just wondered whether it could have lightly damaged or seized anything internally. Ill have to give it a thorough check/anti-freeze top up later today.

Cheers

merlin · 31 Jul 2008 at 08:42

Overlag said:
how hard is to to check:
oil
coolent
tyre pressures x4 (plus spare if u have one)

weekly/monthly? each takes less than a minute ffs.

that takes a lot less time then the car dying on the way to work and wasting a whole day getting it recoverd, then weeks getting it repaired.... Thats REALWORLD btw.

Ok, don't cry. :confused:

I didn't say it was hard. I inferred I couldn't be bothered to check REGULARLY.

I do check monthly, but I wouldn't call monthly regular.