James Trickett

Faulty power steering / belt slipping?

13 posts in this topic

I've just got back from France, and whilst over there my power steering went heavy and there was a burning rubber smell. Later that day it was fine so I decided to drive it back to the UK as normal. The power steering was intermittently heavy and the car temp was high at one point.

 

Despite this, I drove the 700 miles back no problem and after doing some research I'm thinking it's the serpentine belt, so I've ordered a new one and taking it down to my mates garage on Monday.

 

I understand that the belt drives the power steering, water pump and alternator so I'm sure I'm heading in the right direction, but want to make sure I cover all bases. 

 

Question is, what else could it be other than a worn belt? I'm thinking it could be the crankshaft  pulley. I've had a look and everything is spinning, although, it doesn't speed up with revs. Also wondering if it could be a tensioner, but don't want to replace everything if it's not necessary.

 

The car is a 2006 535d

 

Any help is much appreciated!

Edited by James Trickett
No spaces

Share this post


Link to post
Share on other sites

Cheers for your feedback.

 

Gone to start the car this morning and it's flashed up with servotronic failure, then numerous other warnings on the idrive and now it won't start due to a dead battery.

 

So the alternator has clearly not been working either, so it's all definitely related to the belt...

 

Question is, how do I know if it's something other than just the belt that's causing the issue? If the alternator was faulty, could it cause issues with the belt not spinning fast enough for power steering and the water pump?

 

There seems to be a lot of possibilities, but it'd be great if I could diagnose the issue so I can change parts whilst I'm doing the belt.

 

 

 

 

Share this post


Link to post
Share on other sites

The alternator failing would be the electric gubbins inside it, not the shaft seizing/failing unless the bearings were knackered. Seeing as everything is affected i would say that points to the belt/pulley system not performing its job or driving the ancillaries. 

Share this post


Link to post
Share on other sites

You seem to have a good handle on the problem.

 

It's extremely likely to the crankshaft pulley and there are now a few quality aftermarket replacements available. At this stage it should be fairly obvious with a mirror on a stick.

 

Could be a seized tensioner or pulley too but the crankshaft pulley is a common failure.

Share this post


Link to post
Share on other sites

I decided to jump start it last night. It fired straight up and everything worked perfectly with no warnings at all. I drove it for around 30mins on a mixture of roads and there were no signs of any issues.

 

The power steering worked at all speeds and the alternator seemed to be charging the battery. Although the engine temp did get to around 98, it didn't go above 100 even when driven quite hard.

 

Sorry if it's a daft question, but what should I look for with a mirror on a stick, presume it's a lack of movement on one of the components? Would that show if it's a tensioner or pulley before I take the belt off?

 

Also, which aftermarket pulleys have got a decent reputation? I've seen a few online but don't want to be replacing it again in 6 months.

 

Cheers for all your help so far!

 

 

Share this post


Link to post
Share on other sites

If the crank pulley is on the way out you should be able to see the inner rotating faster than the outer and the rubber part looking a bit of a mess. It often wobbles a lot too.

 

If another tensioner is sticking then you might see the pulley pause whilst the belt tries to continue.

 

If the belt is jumping around then the spring loaded tensioner is sticking or has failed.

 

I can't remember who does crankshaft pulleys but someone like Meyle or Febi Bilstein should be a good bet.

 

 

James Trickett likes this

Share this post


Link to post
Share on other sites

change it before it fails and takes the radiator out with it!  The smell of burning rubber and heavy power steering is exactly how mine started, worked fine some times and not other then simply fell apart reaking havoc!

James Trickett likes this

Share this post


Link to post
Share on other sites

On mine it was the crank pulley as already stated. The inner rubber 'doughnut' had started to perish which meant the the outer portion which drives the belt wasn't always travelling at the same speed as the crankshaft, if that makes sense. Whilst trying to diagnose it (having been trailered home) I only found it as the outer part fell off :o

James Trickett likes this

Share this post


Link to post
Share on other sites

The inner doughnut, smelt of burning rubber one day and PAS went heavy, I could see sometimes at idle the pullies and belts stopped moving and the alternator light came on, made worse if the AC was on.  Another time it would be ok for a bit.  then it fell off, luckily with no damage but you could see the potential from the from the size/weight of the thing spinning.  Mine fell of at idle, but imagine it at 5,000 rpm?!  It could seriously do some wrecking under the bonnet!!  If you replace the belts (recommended)  make sure you get the right AC belt - there may not be a tensioner and its an Elastic belt, so note the length from the old one as there are several different lengths and its a PITA to find the right one without getting the size from the markings on the old one, there were a couple that were only 4-5mm different but you'll never get the belt on if its too short and may slip if too long.  There was a thread on another forum with a guide to getting the AC belt on/off but have not still got it, sorry :(

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now