Will a D5 engine run without a tensioner?

Leamy · Jun 20th, 2022, 17:15

The tensioner on my S80 D5 snapped off the engine block, leaving part of the bolt in the engine and taking a bit off the block as well.
After being told by numerous garages that it’s not repairable and a new engine is required, a local engineer has found a belt that fits the rest of the system missing out the tensioner.
The engine and car are running.
Will they keep running and apart from the belt snapping are there any other dangers involved in running the engine without a tensioner?

Dippydog · Jun 20th, 2022, 18:23

I imagine the belt will stretch in use and without the tensioner there to take up the slack you'd run the risk of the belt skipping teeth on the pulleys or coming off them altogether.Personally it's not something I'd risk.The bit of the block that's broken off has it compromised the block i.e. breached a water or oil gallery? if not might it be possible to drill out the broken bolt[even if it means lowering the subframe/engine to get clearance to get a drill at it?

Leamy · Jun 20th, 2022, 18:33

No damage to the engine itself, but even if the remainder of the bolt is taken out there is not a flat surface to put the new tensioner onto due to the missing chunk.

Bonefishblues · Jun 20th, 2022, 19:29

What's the worst that can happen?

Crack on.

abdiel · Jun 20th, 2022, 19:43

Quote:

Originally Posted by Leamy

No damage to the engine itself, but even if the remainder of the bolt is taken out there is not a flat surface to put the new tensioner onto due to the missing chunk.

Surely 'Chemical Metal' would fettle that? It can be drilled, ground & sanded, filed etc. The secret to getting a good bond is of course to make sure the substrate is spotlessly clean & oil/grease free. As stated earlier above, the snapped bolt can be removed so no reason you would need a 'new' engine & tbh, there is no way I would run the motor without a tensioner! If it was safely 'doable' then the manufacturer would not have fitted one in the first place?

Tannaton · Jun 20th, 2022, 23:16

There's a number of ways that can be repaired... I would get the old bolt out, put a new long bolt in and then build up the metal with aluminium wire in a MIG welder. Then remove the bolt (the ali weld won't stick to it), re-tap the hole and grind/sand it flat again.

Time consuming, requires skill and special kit but much cheaper than a new engine....

Jun 20th, 2022, 17:15	#1
Leamy New Member Last Online: Jul 15th, 2022 12:24 Join Date: Jan 2021 Location: Glasgow	Will a D5 engine run without a tensioner? The tensioner on my S80 D5 snapped off the engine block, leaving part of the bolt in the engine and taking a bit off the block as well. After being told by numerous garages that it’s not repairable and a new engine is required, a local engineer has found a belt that fits the rest of the system missing out the tensioner. The engine and car are running. Will they keep running and apart from the belt snapping are there any other dangers involved in running the engine without a tensioner?

Jun 20th, 2022, 23:16	#6
Tannaton Bungling Amateur Last Online: Today 16:37 Join Date: Aug 2014 Location: Beverley, East Yorks	There's a number of ways that can be repaired... I would get the old bolt out, put a new long bolt in and then build up the metal with aluminium wire in a MIG welder. Then remove the bolt (the ali weld won't stick to it), re-tap the hole and grind/sand it flat again. Time consuming, requires skill and special kit but much cheaper than a new engine.... __________________ 2011 XC90 D5 Executive 2003 C70 T5 GT 2012 Ford Ranger XL SC 1977 Triumph Spitfire 1500 1976 Massey Ferguson 135

Jun 20th, 2022, 18:23	#2
Dippydog Premier Member Last Online: Apr 25th, 2024 17:55 Join Date: Jun 2016 Location: S****horpe	I imagine the belt will stretch in use and without the tensioner there to take up the slack you'd run the risk of the belt skipping teeth on the pulleys or coming off them altogether.Personally it's not something I'd risk.The bit of the block that's broken off has it compromised the block i.e. breached a water or oil gallery? if not might it be possible to drill out the broken bolt[even if it means lowering the subframe/engine to get clearance to get a drill at it?

Jun 20th, 2022, 19:29	#4
Bonefishblues Premier Member Last Online: Today 16:43 Join Date: Oct 2014 Location: Near Bicester, Oxon	What's the worst that can happen? Crack on.

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