Drive belt replacement

[Kevin Smith]

Can anyone help please? I’m trying to replace the drive belt on my 2008 Is 250 but just can’t see how to get the belt on as it’s too tight.

people on various forums talk about releasing the tension via the tension pulley however the pulley on my car appears to be ridged and held in place with a bolt hence no way to release tension!

Have I missed something, how do I release and increase the drive belt tension?

Thank you in advance 🙂

[johnatg]

Here's a self-explanatory drawing of how to release (and keep it released) belt tension. Simply use a ring spanner on the bolt you mention! Make a drawing of the routing before you remove the old belt.

 

 

[Kevin Smith]

Thanks John, I was turning the tension bolt the wrong way! 

Now the drive belt is on the car won’t fire up. It ran before the belt was fitted and turns over fine but won’t start. The belt broke whilst driving on Christmas Day.

Any ideas?

Thanks again 🙂

[johnatg]

Did it stop when the belt broke? It should run - the belt doesn't drive anything vital to the engine running in the very short term. See if it runs with the belt removed. If it does, it points to one of the items driven by the belt having seized - aircon compressor, alternator, tensioner, idler pulley, water pump? Don't run for more than a few seconds without the belt on - no water circulation

If it doesn't then you have another problem and we need diagnostic codes.

[Texas]

I understand the car will/should run without an Aux belt but when the original belt broke when in use it may have damaged another component, a crankshaft posistion sensor for instance which will be essential for the car to run. Needs a closer inspection above just replacing the belt and try to find out why the belt broke in the first place perhaps it was aged or some physical contact occurred.

paul m.

[johnatg]

I understand the car will/should run without an Aux belt but when the original belt broke when in use it may have damaged another component, a crankshaft posistion sensor for instance which will be essential for the car to run. Needs a closer inspection above just replacing the belt and try to find out why the belt broke in the first place perhaps it was aged or some physical contact occurred.
paul m.

That's sort of what I was getting at coming from a different direction.

But I suspect a seizure - these belts almost never break. A sudden seizure may have broken it. Or a gradual one but then I would have expected noise.

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[Kevin Smith]

Thanks for your help 🙂

The engine did start and run fine following the belt breaking. Once the new belt was fitted a few days later the car wouldn’t start. I did remove the belt but that didn’t make any difference. I have checked all the fuses and connections and can’t find any problems. I’m guessing one of the electrical components is at fault so will get a mobile diagnostic service to check it out.