Stevie_G
New Member
- Posts
- 3
- Location
- North East
Just recently iv had a deep knocking occur maybe 4-5 times when starting from cold. Once the truck has the slightest bit of heat, the knocking stops completely. It starts ok, and only has the usual occassional puff of black smoke from the exhaust....... pulls like a train.
At first i though it was either a detonation or bottom end. It definatly had that 'metallic' sound to it.
Firstly checked the valve clesrences and made sure non of the valve caps where hiding in the sump.
Secondly i removed the fan belt and ran the engine from dead cold............... no knocking. I checked all the pulleys and found the DC alternator bearings where a little rough, but not excessive. Being resourceful i had a brand new alt in the garage. Replaced, fit belt and noise reappeared.
So i removed the belt once more. Started the truck and the knocking disappears.
I double/treble checked the pulleys once more and there is very minimal play in the vicious fan hub and belt tensioner and no play in the (new) water pump and power steering pump.
I removed the timing belt cover to see if anything was potentially catching behind the hub bearing, but all looks good.
Whilst the cover was off i also check the engine timing belt.........which surprisingly was spot on, (12 o clock on crank (with timing pin in flywheel), FIP pin slipped straight in and cam pulley lines up.) and no debris or belt chaffing.
Anyone had a similar fault? Im baffled. Im thinking possibly fan hub bearing but this is expensive considering they recommend a new timing belt cover at approx £150!
Any help would be greatly appreciated,
Thanks Steve
At first i though it was either a detonation or bottom end. It definatly had that 'metallic' sound to it.
Firstly checked the valve clesrences and made sure non of the valve caps where hiding in the sump.
Secondly i removed the fan belt and ran the engine from dead cold............... no knocking. I checked all the pulleys and found the DC alternator bearings where a little rough, but not excessive. Being resourceful i had a brand new alt in the garage. Replaced, fit belt and noise reappeared.
So i removed the belt once more. Started the truck and the knocking disappears.
I double/treble checked the pulleys once more and there is very minimal play in the vicious fan hub and belt tensioner and no play in the (new) water pump and power steering pump.
I removed the timing belt cover to see if anything was potentially catching behind the hub bearing, but all looks good.
Whilst the cover was off i also check the engine timing belt.........which surprisingly was spot on, (12 o clock on crank (with timing pin in flywheel), FIP pin slipped straight in and cam pulley lines up.) and no debris or belt chaffing.
Anyone had a similar fault? Im baffled. Im thinking possibly fan hub bearing but this is expensive considering they recommend a new timing belt cover at approx £150!
Any help would be greatly appreciated,
Thanks Steve
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