Car got a bit warm today.........

[M3 SOY]

OK, an unhappy camper now. I went on a long run last weekend in the 4.6 iS and car was amazing. However, today, after picking up the kids from school I was sat in traffic when the "check coolant" signal came on. Temperature gauge read normal, however, just as I got home which was about 3 mins later a minging smell entered the car and low and behold steam started emanating from the bonnet.

I allowed the car to cool and checked the  expansion tank which was empty. I put approx 2.5 litres of fluid in and it doesn't seem to have lost any since.

The car had been sat on the drive since Saturday night and I can see no sign of any coolant leak anywhere.

I'm struggling to understand how the car got so hot so quickly but that the temp gauge didn't seem to go above normal really.

Before I head for the local indy repair shop I thought I would ask if anyone had any previous experience of such a problem. Are these cars prone to losing a bit of fluid over time? I must admit I had not checked it recently.

[X5Sport]

Is the coolant cap properly tightened down?  Any sign of leaks/stains to give a clue as to where it's losing it from?  Wet carpets inside?  Puddles under the car (yeah I know it's raining so that one might be a challenge!!)?

Not unknown for this to happen and can be anything from a seal on the tank cap failing to hold pressure so it 'boils away' to, defective (cracked) coolant tanks, to hoses to radiators to head gaskets.

The temperature gauge can be a bit slow on the uptake.......or worse, defective......and anything over half-way means go looking for a problem.

If nothing obvious then a pressure test will be needed.

[IanP]

Had loads of problems with my 4.6 losing coolant. If the mileage is 75000+ and the hoses are original, they ALL need changing. Mine blew the top hose then two leading into the heaters in quick sucession. When the water temp gauge moves its usually too late, watch the oil temp gauge. Mine sits just below halfway, and as you lose coolant it will move  to just above halfway, usually just before the low coolant level alarm goes off.
As X5Sport says, check the coolant tank for cracks, but you need to have the engine sitting idling to get the system pressurised these engines seem to run at high pressure. My hoses did not leak with the engine standing, only when hot, there isnt a lot of coolant in the system for the size of engine so it does not take much of a loss to overheat

[M3 SOY]

Thanks guys, I can't see anything wrong anywhere, plenty of pressure when I took the cap off, no signs of any leaks. It's just had inspection 2 with new rocker cover gaskets, breathers and oil separator so pretty annoyed. Hoses look in fairly good nick too. Oh well off to the Indy for a pressure test it is then!

Thanks for the input guys, much appreciated. 

[petert]

Thermostat siezed?
Peter T

[shadrack]

[quote="petert"]
Thermostat siezed?
Peter T
[/quote]

Worth a look, but I'm sure when mine was stuck open, I was told the failsafe bit of them tends to make them stick open when failing (I might be wrong though)

[M3 SOY]

Just off to collect from the Indy now.....split hose, lets hope the damage isn't too bad  :-[

[IanP]

[quote="M3 SOY"]
Just off to collect from the Indy now.....split hose, lets hope the damage isn't too bad  :-[
[/quote]

If one has gone I would really recommend changing them all. I learnt my lesson after the third one went in a month. Strangely they all looked in perfect condition, no ballooning, just the tiniest split on a bend.

[shadrack]

[quote="IanP"]
[quote="M3 SOY"]
Just off to collect from the Indy now.....split hose, lets hope the damage isn't too bad  :-[
[/quote]

If one has gone I would really recommend changing them all. I learnt my lesson after the third one went in a month. Strangely they all looked in perfect condition, no ballooning, just the tiniest split on a bend.
[/quote]

i would agree with this, i learnt the hard way on a 328i, problem is if next time you dont notice, and boil the engine and crack the head as i did

[jaynana]

one of the easiest ways to blow an engine i think.. although rare

temp guage is very unlikely to be noticed. isn't there a light or a simple audible indicator if the engine temp is rising beyond safe limits.. ?

[M3 SOY]

The Indy I went to said that the rest of my hoses are all in good shape so I should be ok!! If anyone is in the Notts area I would thoroughly recommend Series 9 by the ice rink. He got me in same day, was good value, much less than Sytners put it that way! Furthermore, the car came back absolutely gleaming.

Honestly everyone in there is great, from Dave the owner, through to the techies who worked on the car. Polite, honest and totally genuine! I know where my servicing is going to be done from now on!!!