Worried !

E39MSport

E39 hasn't moved in 2 weeks. It's ungaraged and pretty much in the shade all day.
I fired it up for an hour last week - no problems.

Decided to do same today. After battling to open the door, she turned over very slowly and finally fired. Temp gauge read -7.5 c.

However, it sounded extremely rough and lumpy like something mechanical was knocking and not just a misfire type noise. I turned it off after about 5 seconds.

I can't open the bonnet to check whether the coolant is frozen.

Anyone know what might have caused the noise and whether any damage may have been caused? The engine is in tip top shape.
What the hell can I do to get her going in the short term or is it ok to leave her like that until the freeze is over?

I have a trickle charger and Noah cover on order but given the weather they'll probably show up just when they're not critically needed.

Many thanks,

v300

Most likely some frozen moisture on an underbonnet electrical connector causing erroneous engine running.
A dark car like that will defrost during a sunny day and re-freeze at night.
Trickle chargers are worth their weight in gold now for keeping stored cars batteries alive in this cold spell.

As for the coolant being frozen, it may well be (devils advocate) but it would not cause the engine to run exactly like that.

However if the block is frozen, the water pump would not rotate,
so check to see is the water pump turning the next time you get
your bonnet open and engine running.

Hopefully she just needs to be warmed up and dried out
with a tick over for 30 minutes or a 15 minute drive.:D

no1beemerfan

E39MSport wrote: »

E39 hasn't moved in 2 weeks. It's ungaraged and pretty much in the shade all day.
I fired it up for an hour last week - no problems.

Decided to do same today. After battling to open the door, she turned over very slowly and finally fired. Temp gauge read -7.5 c.

Sounds to me like your battery is pretty flat.

E39MSport

Thanks for responses.

Yeah, bettery is running flat so getting a trickle charger attached soon.

I think I'll fire it up again once I get the doors and bonnet opened. I'll let you know.

BlackWizard

If it helps, this morning it sounded like a piston was wacking the top of the engine. I let it idle for 5min then just drove to work. The noise was gone by the time I got to work. This happened a few days ago too.

I remember it happening last year too during the previous cold spell. My car was okay after it then too. I had to replace my battery around the same time too. But it was an old battery and died an honourable death with nothing to do with the cold.

Heroditas

BlackWizard wrote: »

If it helps, this morning it sounded like a piston was wacking the top of the engine. I let it idle for 5min then just drove to work. The noise was gone by the time I got to work. This happened a few days ago too.

I remember it happening last year too during the previous cold spell. My car was okay after it then too. I had to replace my battery around the same time too. But it was an old battery and died an honourable death with nothing to do with the cold.

Sounds like poor oil pressure.

biko

If you can - get it warm and dry again, maybe in a heated garage overnight in town. Then buy a big tarp and cover the car with, to keep moisture off it.

E39MSport

Got it going. Noise abated after about 60 seconds. Probably oil pressure from temperature.

Cheers,

GTE

Yeah, a big problem I read about cars in very cold climates would be that sometimes if the wrong oil for the climate is put in the car it gets very thick and problems can emerge. The wrong oil over there could be the right oil over here for the most part if you get me. The oil we normally take for granted cant operate in the cold as well. So oil pressure takes a while to get going. Its taking longer for my little tapping noise to go as the oil is taking longer to get to the things that tap
Maybe anyway

Anan1

Might it just have been ice formed from condensation on the viscous fan blades? I'm not liking the sound of the low oil pressure explanation at all. Although I do remember seeing a picture once of Luftwaffe ME-109 pilots on the Eastern Front having to warm their engine oil in a cauldron over a fire before putting it back into the plane.

tpotter

As others have mentioned, Cold Weather can play havoc on a battery, especially if you aren't using it everyday...

Matt Simis

I have Mobil 1 0w-40 in my old (1993) BMW and have had none of the issues you described (heh, I have other unrelated problems!) and Im out in the sticks in the midlands, car outside and undriven. Ive read about people who had "cold engine knock" using 10w and above oils that fixed it by using 0w.

Fun fact about 0w motor oils, they are the same thickness as 5w but are chemically enchanced for low temp operation (as in really low temp, -40c). I mention this as there is a common misconception that 0W is too thin for some cars.

0w-40 is BMW approved for all climates too, but Ive seen some weird comments and fear about using it on some forums. To me, as its got the best low temp and best operating temp performance, its a no brainer. Im also a big fan of fully syntheic oils (swithed Gearbox oil to Redline MT-90, way heavier than stock oils but ironically better in low temps than BMW generico version).


A note from captain Mobil 1

https://www.youtube.com/watch?v=sW3w0bKurbg

PS: And no, there is no Halfords branded 0w-40 for you cheapskates