Thread: What's that noise?

Sounds like a perfect description of a broken Td5 harmonic balancer to me

Deano

With the serpentine belt off and engine running for a very short while(from cold) you should be able to see it wobbling about, instead of it running smoothly.

We did basically the same thing with my brothers TD5 looking for a clack clack sound too .. easy to spot.

With the serpentine belt off and engine cold, you will have a few minutes before danger could arise in that the water pump won't be pumping water around, but you won't need more than a few seconds idle time to spot a broken balancer.

Originally Posted by DeanoH

Sounds like a perfect description of a broken Td5 harmonic balancer to me

Deano

Hi Guys,

I'm new to DIIs, so please forgive my ignorance. What's the problem with Td5 harminic balancers? I've never had one fail on any of my previous vehicles including Fords, Nissans, a couple of Toyotas, a Holden 202 and my 408,000 km 300Tdi Discovery (admittedly the only diesel). Why do Td5 ones fall apart? Are there more reliable aftermarket alternatives? Thanks,

Hi Leo109, the Td5 harmonic balancer/crankshsft pulley is a complex piece of gear when compared to a simple one piece job. There's the 'main' pulley' part which is similar to an old Holden ie. steel outer rubber bonded to a steel inner but with an additional 'piece' bolted to it in the centre that connects to the crankshaft. Unlike many other harmonic balancers/crankshaft pulleys it is not affixed to the crankshaft using a taper/key method but bolted straight on using a bloody great high tensile bolt done up extremely tight to hold it in position. It's worth Googling 'Td5 crankshaft pulley' images and looking at the pictures to get a good idea of how it's all put together.

The down side is that after many years of faithful service it fails. This can be either the rubber failing and the main pulley assembly separating (just like an old Holden) or the lugs failing that connect the centre piece to the outer. You really need to look at the pics to get an idea of what I mean here. The clacking noise you hear is the inner and outer 'pieces' moving independently and striking each other.

The long and short of it means a replacement crankshaft pulley is required. As this is a critical component I would suggest going original LR and avoiding cheap would have been if they could have been after market copy's. It's a quality thing.

It's a bugger of a job to replace. After removing the shroud, fan belt etc the next thing that needs to be removed is the viscous hub assembly which can be extremely difficult if it hasn't been removed since new as it is likely to be very firmly affixed to its hub. This is NOT a left hand thread as many vehicles are. tip . if the fan belt goes over the fan pulley its LH thread if it goes under as in Td5 it's RH (normal) thread. Quite often a 'special tool' is needed to hold the fan hub whilst using a viscous hub spanner to remove the fan viscous assembly. This is the easy part

Undoing the large nut that holds the harmonic balancer assembly to the end of the crankshaft is not a job for the faint hearted. I can't remember what it's done up to but it's bloody lots and after 18 years or so it's even tighter. There's a pretty good write up from Alien ? I think which suggests how to do this. A 'special tool' is definitely needed to re assemble and do up to the required torque along with a large 3/4" drive torque wrench to achieve the correct tension. If you're not into serious mechanical work definitely a job you pay someone else to do IMO.

Enjoy

Deano