E61 - N53 - overheating error

[Ian Geary]

Morning all

Had my first breakdown in the bmw today. The engine cut power drastically with the warning "overheating - moderate driving"

As I was going up a steep narrow hill, it cut out shortly afterwards.

No fluid was leaking out, so after leaving it to cool for 5 mins, it restarted, and I limped with heaters on to my work car park a few mins away.

Having a look, I can see the aux belt has become shredded somewhat, which is probably either a symptom or cause of this (although the belt is still in place)





So can anyone suggest what might be up here?

- the water pump is electric I think, so shouldn't be affected by the belt directly?

- the fan still spins, so isn't jammed?

Anything else I should check.

I'm 20 miles from home, half of which is motorway, so wondering if I limp home, or just book my breakdown truck now to get recovered home

Tia

Ian

[bmwmike]

Its probably the electric water pump giving up the ghost, but your serpentine belt is also shredded. Has this engine been maintained? Its probably worth reading codes and seeing what is up.

As you're stuck, i'd be tempted to limp personally, but... your risk. It could toast the engine. Keep the heaters etc on full blast and windows down, might help.

The serpentine belt is at risk of being ingested into the engine btw, which will also kill your engine as it clogs oil passageways.

[pmorg4]

As noted above on both points, you're taking quite a risk if you drive it. The overheating isn't related to the belt, but it's quite likely that the electric pump is dead or dying, and a shredded belt needs sorting ASAP.

[bmwmike]

pmorg4 said:

As noted above on both points, you're taking quite a risk if you drive it. The overheating isn't related to the belt, but it's quite likely that the electric pump is dead or dying, and a shredded belt needs sorting ASAP.

Thinkin more about it, if the FEAD belt snaps the alternator won't be charging so it'll not get far anyway.

[Ian Geary]

Morning all,

Thanks for the replies. I can give an update

I got the car recovered from work to home, after reading up on horror stories about ingesting bits via the crank seal.

At lunch I'd checked on it, and the water pump was cycling on and off intermittently.

By evening, the battery was drained so it wouldn't start, but luckily the breakdown chap had a booster pack.

Getting the car home and having a proper look, I can see the water pump wiring had been damaged - probably by being wrapped in belt debris?




This was causing the pump to be engaged (as the wires touched presumably it shorted it on)

I can only assume then that

- the belt slipped off, probably caused by a gasket leak I have somewhere

- the debris damaged the water pump wiring

- this in turn might have caused the water pump to not work, causing the overheating error?

• however, the wiring didn't cause a short to ground (which would have blown a fuse) or break the circuit open, which would have stopped it completely, so I'm not entirely sure *

- the fan spins and the radiator isn't blocked, so this link to the water pump is all I can think of.

Next job will be to get the crank pulley off and check the status of the crank seal. Then, clean up, and replace the belt and the 2 plastic idler pulley, one of which has been chewed up quite badly.

The water pump looked reasonably new when I got the car 2 years ago, but potentially it's failing? I'll do the belt first, and take it from there.


Ian

[bmwmike]

Wow, sounds like you did the right thing recovering it.

How you describe it sounds plausible to me - belt damaged wiring. Fingers crossed the oil seal is fine but if it's got belt sticking out of it you may have further issues. The oil seal itself is not that hard to replace.

New belt and tensioner are a must. Hopefully the pump wiring can be repaired.

[Touring442]

N52/N53 belts fall off because the spring loaded tensioner wears out, operates at an angle and throws the belt off after rubbing it against the front of the engine for a few hundred miles. Engine ingestion of the belt can happen but it's very rare - neither I nor anyone I know has ever seen it happen but it's not impossible.

If the pump is original it's not a bad plan to replace it at this point. It's the pivoting spring loaded part of the tensioner that causes the fault but a complete tensioner isn't much new. Go for a good make like INA, FAG etc.

Edited by Touring442 on Thursday 8th September 11:17

[Touring442]

53 quid, a easyish job as well.

https://www.eurocarparts.com/tensioners-idlers-and...

[bmwmike]

Touring442 said:

53 quid, a easyish job as well.

https://www.eurocarparts.com/tensioners-idlers-and...

Just did mine recently - is an straightforward job, but a proper torx plus socket is a must if you don't want it slipping. I forget the size - TP65 possibly - and a new bolt which came with the tensioner anyway.

[Court_S]

bmwmike said:

Just did mine recently - is an straightforward job, but a proper torx plus socket is a must if you don't want it slipping. I forget the size - TP65 possibly - and a new bolt which came with the tensioner anyway.

Think it’s a T60 from memory.

[Court_S]

Ian Geary said:

Morning all,

Thanks for the replies. I can give an update

I got the car recovered from work to home, after reading up on horror stories about ingesting bits via the crank seal.

At lunch I'd checked on it, and the water pump was cycling on and off intermittently.

By evening, the battery was drained so it wouldn't start, but luckily the breakdown chap had a booster pack.

Getting the car home and having a proper look, I can see the water pump wiring had been damaged - probably by being wrapped in belt debris?




This was causing the pump to be engaged (as the wires touched presumably it shorted it on)

I can only assume then that

- the belt slipped off, probably caused by a gasket leak I have somewhere

- the debris damaged the water pump wiring

- this in turn might have caused the water pump to not work, causing the overheating error?

• however, the wiring didn't cause a short to ground (which would have blown a fuse) or break the circuit open, which would have stopped it completely, so I'm not entirely sure *

- the fan spins and the radiator isn't blocked, so this link to the water pump is all I can think of.

Next job will be to get the crank pulley off and check the status of the crank seal. Then, clean up, and replace the belt and the 2 plastic idler pulley, one of which has been chewed up quite badly.

The water pump looked reasonably new when I got the car 2 years ago, but potentially it's failing? I'll do the belt first, and take it from there.


Ian

Sounds like you’ve hopefully gotten away without too much damage.

Which gasket do you suspect - valve cover or oil cooler / filter housing?

[Ian Geary]

Court_S said:

Sounds like you’ve hopefully gotten away without too much damage.

Which gasket do you suspect - valve cover or oil cooler / filter housing?

Frankly, all of them!

And who knows, maybe me replacing the cam cover one just made it worse?

It went from max to min oil in about 800 miles, and the metal plate under the engine is awash with fresh oil.

Still, it keeps corrosion at bay....

[Court_S]

Ian Geary said:

Frankly, all of them!

And who knows, maybe me replacing the cam cover one just made it worse?

It went from max to min oil in about 800 miles, and the metal plate under the engine is awash with fresh oil.

Still, it keeps corrosion at bay....

Ouch, that doesn’t sound too clever. Any visible signs of leaks since you did the gaskets?

[bmwmike]

Check CCV too. That can increase oil consumption