What if? (Technical)
Discussion
Hi
If my noisy and getting noisier air conditioning compressor seized, I assume that the belt would rapidly disintegrate and fall off. This would mean no more power steering I assume.
I also assume that the car would remain driveable.
I've got a beautiful reconditioned pump but can't get it fitted until next week.
Do you think my assumptions are correct?
Cheers!
If my noisy and getting noisier air conditioning compressor seized, I assume that the belt would rapidly disintegrate and fall off. This would mean no more power steering I assume.
I also assume that the car would remain driveable.
I've got a beautiful reconditioned pump but can't get it fitted until next week.
Do you think my assumptions are correct?
Cheers!
That is exactly what happened on a 2.8 Ford engined car I had. No warning noises, just a sudden loss of charging as the belt shredded on a seized compressor pulley.
Of course, as the MX5 is potentially different in compressor and drive belt configs, so as they say on BBC, other outcomes are available...
Of course, as the MX5 is potentially different in compressor and drive belt configs, so as they say on BBC, other outcomes are available...
I chickened out of driving the car at the weekend and borrowed a friend's Celica. My car has gone in to have the smart reconditioned unit fitted today. I realise that the unit is clutched but presumably that could have failed. The main noise was a chuffing which really sounded like the actual pump rotating. The other noise was a high pitched whistle at speed which would disappear sometimes if I cruised at a slightly different speed. Maybe a total seizure was unlikely. I'm relieved that it didn't happen but in the interests of science we'll never know what would have happened to the belt and power steering. I suspect that the demise of the belt would have been extremely rapid! It is hot and sticky in Kent today so I'm looking forward to testing the aircon later. Or having the roof down without a cacophony of alarming noises.
PATTERNPART said:
I chickened out of driving the car at the weekend and borrowed a friend's Celica. My car has gone in to have the smart reconditioned unit fitted today. I realise that the unit is clutched but presumably that could have failed. The main noise was a chuffing which really sounded like the actual pump rotating. The other noise was a high pitched whistle at speed which would disappear sometimes if I cruised at a slightly different speed. Maybe a total seizure was unlikely. I'm relieved that it didn't happen but in the interests of science we'll never know what would have happened to the belt and power steering. I suspect that the demise of the belt would have been extremely rapid! It is hot and sticky in Kent today so I'm looking forward to testing the aircon later. Or having the roof down without a cacophony of alarming noises.
Good that you are getting it sorted out. Just to make sense of it there are two types of bearing failure AND pump seizure too - 1, the centre bearing in the pulley can fail throwing the belt whilst the AC is switched off. 2: The compressor bearings fail while the AC is on, throwing the belt (the pulley bearing is still when the pump clutch is engaged). 3, the compressor pump internals seize up, guess what, throws the belt! Well the plot thickens. The reconditioned pump is on. Airconditioning blowing nice cold air on demand. BUT the noise is is still there and getting worse. In fact, as I was manoeuvring the car this morning the noises seemed to correspond with steering input so maybe it's that!?
On start up I can even feel tremors through the steering wheel if i turn it side to side.
The fluid is at the optimal level - I seldom look at that and would not have been surprised to find that it had dropped - It hasn't.
I'll drop in to Freelance Mazda tomorrow or Friday and get them to try running the two units separately to really make sure.
I hate having a car that makes knackered type noises!
On start up I can even feel tremors through the steering wheel if i turn it side to side.
The fluid is at the optimal level - I seldom look at that and would not have been surprised to find that it had dropped - It hasn't.
I'll drop in to Freelance Mazda tomorrow or Friday and get them to try running the two units separately to really make sure.
I hate having a car that makes knackered type noises!
Sounds like a dodgy PAS pump.
Another option could be the crank pulley. The drive for the PAS and AC on the crank is on a rubber layer. If that's disintegrating, it could cause some problems.
However, that you can feel some juddering or vibration through the steering suggests to me that it's the PAS pump.
Another option could be the crank pulley. The drive for the PAS and AC on the crank is on a rubber layer. If that's disintegrating, it could cause some problems.
However, that you can feel some juddering or vibration through the steering suggests to me that it's the PAS pump.
Have you checked the fluid level in the PAS?
I can confirm that everything works fine without the belt - it's power ASSISTED steering - there is still a mechanical connection.
I drove mine around for a couple of weeks after I pulled the a/c out, and before I got around to getting the shorter belt. Bit of a workout parking, but otherwise entirely driveable.
I can confirm that everything works fine without the belt - it's power ASSISTED steering - there is still a mechanical connection.
I drove mine around for a couple of weeks after I pulled the a/c out, and before I got around to getting the shorter belt. Bit of a workout parking, but otherwise entirely driveable.
I got my own friendly garage to have a look. They tightened the belt quite a bit by the look of it which took under 5 minutes. Silence. A slight thud as the aircon is switched on and kicks in but running quietly so happy.
The chattering is slowly coming back however! I learned that one of the bolts holding the aircon pump bracket to the engine is missing and stripped and not easy to fix due to the location. I suspect that the aircon specialist left the belt slack on purpose to be kind to the bracket - he tightened the 3 good bolts and Loctited them. Without fully understanding the geometry of the respective pulleys I can't say if this is the culprit.
I'm going to put a new belt on on the theory that one that has been slipping for a while may have suffered and see what happens.
One observation - the mechanism for tensioning the belt seems nicely engineered!
The chattering is slowly coming back however! I learned that one of the bolts holding the aircon pump bracket to the engine is missing and stripped and not easy to fix due to the location. I suspect that the aircon specialist left the belt slack on purpose to be kind to the bracket - he tightened the 3 good bolts and Loctited them. Without fully understanding the geometry of the respective pulleys I can't say if this is the culprit.
I'm going to put a new belt on on the theory that one that has been slipping for a while may have suffered and see what happens.
One observation - the mechanism for tensioning the belt seems nicely engineered!
A new belt worked wonders! I left it a little bit slack so that there isn't excess load on any pulleys. This gave a brief squeak so I quickly tightened it a little. Probably close to the recommended tension now. It is lovely to have peace and quiet from under the bonnet. My ears are now very sensitive to any slight noise which is exaggerated with the roof down. Sometimes I hear a bit of a noise and find that it is coming from the car behind in traffic. Paranoia is a wonderful thing. I had my hearing checked at work and it is normal for my age group...
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