ZT diesel water pump failure

rikk · 21st April 2023, 21:00

Hello, I have a question regarding my MG ZT CDTi, to do with the water pump and auxiliary belt & tensioner, specifically could a dodgy tensioner cause a water pump to fail quickly?

To give a bit more detail, about 18 months ago the alternator had to be replaced, the belt was pretty worn too so I had that replaced and for good measure I had the aux belt tensioner and waterpump replaced (not that there was a problem but as a precaution as the car had about 180k on it at the time).

All was okay until about 6 months ago when I started hearing some whining noises, I thought they were from the gearbox as it seemed to only happen when the car was in drive and not when it was in neutral.

Some months later the whining noises stopped and were replaced by some quite loud rattling noises. Also started getting some squealing from the aux belt when the steering was on full lock.

I wrongly assumed it was the crankshaft pulley and got one for the mechanic to fit, but when he investigated he found that actually the pulley was fine and the noise was the waterpump, the bearings on it were totally shot.

The one I’d had fitted wasn’t a cheap dodgy one off ebay so it seems very strange that this happened. He suggested that either I’d been unlucky and got a duff pump, or maybe the aux belt tensioner could cause it.

After the new waterpump was fitted, the various noises went away. But recently it’s starting to make some whining noises from that area again.

So I’m thinking if I leave it then the same thing could happen again. Not sure what to do.

Thankyou.

Mike Noc · 21st April 2023, 22:58

Factory fit water pumps can be good for 300k miles, and aftermarket 60k upwards in my experience, so you would have been better off not changing the water pump.

Did you fit a genuine Corteco crank pulley? If you remove the serpentine and aircon belts then check all the auxiliary pulleys for play and roughness that might help diagnose where the whine is emanating from. Some aftermarket water pumps are noisy from the start but they can still last.

rikk · 22nd April 2023, 07:58

Yes I should probably have left the water pump then, but as the thermostat was stuck too I had it done. The pulley is a corteco one. I'll see if we can identify where the noise is coming from .

Mike Noc · 23rd April 2023, 08:25

Can you post up a sound clip of the noise? It's difficult to diagnose the fault without hearing it. The tensioners aren't known for causing any problems and are usually pretty much bulletproof. As mentioned, with the belts removed, any play or roughness in any of the pulley bearings would be a pointer.

rikk · 25th April 2023, 08:27

Probably difficult to record the noise at the moment - would be hard to hear over the sound of the engine, though i know it's there as i've had the car a long time and know what it sounds like!
May have to wait until it gets worse (which presumably it will), though will see if the mechanic can find anything when he does the oil change next month.
Maybe should have left the other stuff when i had the alternator done, at the time it seemed a good idea to replace some other parts as precautionary maintenance but it may have been find if i'd just left it. When the waterpump failed last time I also had him put on a new idler pulley.
I don't see why a waterpump would fail after only about 15k miles, unless it was a very poor quality (it wasn't a cheap one) or damaged when fitting or if there is something else causing it such as drive belt tension (i mean if it was over tensioned then perhaps that could cause wear? yet at the same time i was getting a squeal from the PS pump which would suggest under tensioned, so that doesn't make sense anyway).

21st April 2023, 21:00	#1
rikk Avid contributor Rover 75 CDTI Join Date: Mar 2007 Location: Ashby de la Zouch Posts: 104 Thanks: 3 Thanked 2 Times in 2 Posts	ZT diesel water pump failure Hello, I have a question regarding my MG ZT CDTi, to do with the water pump and auxiliary belt & tensioner, specifically could a dodgy tensioner cause a water pump to fail quickly? To give a bit more detail, about 18 months ago the alternator had to be replaced, the belt was pretty worn too so I had that replaced and for good measure I had the aux belt tensioner and waterpump replaced (not that there was a problem but as a precaution as the car had about 180k on it at the time). All was okay until about 6 months ago when I started hearing some whining noises, I thought they were from the gearbox as it seemed to only happen when the car was in drive and not when it was in neutral. Some months later the whining noises stopped and were replaced by some quite loud rattling noises. Also started getting some squealing from the aux belt when the steering was on full lock. I wrongly assumed it was the crankshaft pulley and got one for the mechanic to fit, but when he investigated he found that actually the pulley was fine and the noise was the waterpump, the bearings on it were totally shot. The one I’d had fitted wasn’t a cheap dodgy one off ebay so it seems very strange that this happened. He suggested that either I’d been unlucky and got a duff pump, or maybe the aux belt tensioner could cause it. After the new waterpump was fitted, the various noises went away. But recently it’s starting to make some whining noises from that area again. So I’m thinking if I leave it then the same thing could happen again. Not sure what to do. Thankyou.

21st April 2023, 22:58	#2
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,584 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Factory fit water pumps can be good for 300k miles, and aftermarket 60k upwards in my experience, so you would have been better off not changing the water pump. Did you fit a genuine Corteco crank pulley? If you remove the serpentine and aircon belts then check all the auxiliary pulleys for play and roughness that might help diagnose where the whine is emanating from. Some aftermarket water pumps are noisy from the start but they can still last.

22nd April 2023, 07:58	#3
rikk Avid contributor Rover 75 CDTI Join Date: Mar 2007 Location: Ashby de la Zouch Posts: 104 Thanks: 3 Thanked 2 Times in 2 Posts	Yes I should probably have left the water pump then, but as the thermostat was stuck too I had it done. The pulley is a corteco one. I'll see if we can identify where the noise is coming from .

23rd April 2023, 08:25	#4
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,584 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Can you post up a sound clip of the noise? It's difficult to diagnose the fault without hearing it. The tensioners aren't known for causing any problems and are usually pretty much bulletproof. As mentioned, with the belts removed, any play or roughness in any of the pulley bearings would be a pointer.

25th April 2023, 08:27	#5
rikk Avid contributor Rover 75 CDTI Join Date: Mar 2007 Location: Ashby de la Zouch Posts: 104 Thanks: 3 Thanked 2 Times in 2 Posts	Probably difficult to record the noise at the moment - would be hard to hear over the sound of the engine, though i know it's there as i've had the car a long time and know what it sounds like! May have to wait until it gets worse (which presumably it will), though will see if the mechanic can find anything when he does the oil change next month. Maybe should have left the other stuff when i had the alternator done, at the time it seemed a good idea to replace some other parts as precautionary maintenance but it may have been find if i'd just left it. When the waterpump failed last time I also had him put on a new idler pulley. I don't see why a waterpump would fail after only about 15k miles, unless it was a very poor quality (it wasn't a cheap one) or damaged when fitting or if there is something else causing it such as drive belt tension (i mean if it was over tensioned then perhaps that could cause wear? yet at the same time i was getting a squeal from the PS pump which would suggest under tensioned, so that doesn't make sense anyway).