Discussion
Hi all
I'd like some advice please. I'm feeling disgruntled at how a specialist garage is handling a situation and would like a sanity check! (I know it's not quite the subforum for this, but can't see anywhere else it could go)
My 2008 Mustang suddenly developed rough running about 3 months ago. I had the car recovered to an American car specialist.
They informed me that a VCT solenoid had failed. Recommend I replace both solenoids as well as the cam phasers. I agreed, as the phasers are a well known failure point, so made sense to get that sorted while the car was there.
2 weeks later, they called me to say the car was repaired and ready for collection. I took the day off work to travel over and collect it.
Paid, shook hands, and off I went. I soon realised the car wasn't completely fixed - it now drove fine, but the idle was horrendous when the engine was hot. I had to return the car to them and ask my partner to come and collect me. An absolute PITA and I was not impressed.
They've since diagnosed low oil pressure. Recommend a new oil pump. This means undoing all the work I've already paid for, as the pump is linked to the cam phasers.
Another 6 weeks on and the car still hasn't had this additional work done. When I ask for a status check, there's always a delay, waiting on a part, it'll be done soon, etc. Personally, I think they're just getting through their current workload and the car is sitting outside the unit waiting until they've cleared the backlog of pre-booked customers.
A few things as a result of this saga which I am going to raise with them:
- The car clearly wasn't sufficiently tested before being returned
-I don't think the delay is reasonable at this point. The car's been with them for 2 months in total
- Complete lack of communication unless I ask what's going on
But, what I am less sure about..
- Is it reasonable for me to pay what is effectively, double-labour to now replace the oil pump? Should/could the garage have tested the oil pressure? It appears this was a failure point that wasn't diagnosed initially.
Thanks in advance!
I'd like some advice please. I'm feeling disgruntled at how a specialist garage is handling a situation and would like a sanity check! (I know it's not quite the subforum for this, but can't see anywhere else it could go)
My 2008 Mustang suddenly developed rough running about 3 months ago. I had the car recovered to an American car specialist.
They informed me that a VCT solenoid had failed. Recommend I replace both solenoids as well as the cam phasers. I agreed, as the phasers are a well known failure point, so made sense to get that sorted while the car was there.
2 weeks later, they called me to say the car was repaired and ready for collection. I took the day off work to travel over and collect it.
Paid, shook hands, and off I went. I soon realised the car wasn't completely fixed - it now drove fine, but the idle was horrendous when the engine was hot. I had to return the car to them and ask my partner to come and collect me. An absolute PITA and I was not impressed.
They've since diagnosed low oil pressure. Recommend a new oil pump. This means undoing all the work I've already paid for, as the pump is linked to the cam phasers.
Another 6 weeks on and the car still hasn't had this additional work done. When I ask for a status check, there's always a delay, waiting on a part, it'll be done soon, etc. Personally, I think they're just getting through their current workload and the car is sitting outside the unit waiting until they've cleared the backlog of pre-booked customers.
A few things as a result of this saga which I am going to raise with them:
- The car clearly wasn't sufficiently tested before being returned
-I don't think the delay is reasonable at this point. The car's been with them for 2 months in total
- Complete lack of communication unless I ask what's going on
But, what I am less sure about..
- Is it reasonable for me to pay what is effectively, double-labour to now replace the oil pump? Should/could the garage have tested the oil pressure? It appears this was a failure point that wasn't diagnosed initially.
Thanks in advance!
Edited by Rusty_ on Sunday 9th August 15:19
Oil pump failure causing a single phaser to operate incorrectly (with no other issues) would be a pretty odd failure. Obviously it's possible to have 2 components in a system fail at the same time but it's never really that. When people start replacing multiple parts to cure the same problem it is almost always because they haven't diagnosed it correctly.
It wouldn't be normal to start testing oil pressure when you have a cam timing/VCT issue (obviously this being PH someone will be along soon to say this would be the first thing they'd check). I don't know what the minimum pressure on your engine is for the VCT to operate correctly but I'd be very dubious about that diagnosis and need to look into it further.
It seems far more likely to me that they've messed up the phaser replacement (a tooth or so out on the timing on one cam) or something else is going on (dodgy solenoid etc.).
It wouldn't be normal to start testing oil pressure when you have a cam timing/VCT issue (obviously this being PH someone will be along soon to say this would be the first thing they'd check). I don't know what the minimum pressure on your engine is for the VCT to operate correctly but I'd be very dubious about that diagnosis and need to look into it further.
It seems far more likely to me that they've messed up the phaser replacement (a tooth or so out on the timing on one cam) or something else is going on (dodgy solenoid etc.).
Richard-D said:
Oil pump failure causing a single phaser to operate incorrectly (with no other issues) would be a pretty odd failure. Obviously it's possible to have 2 components in a system fail at the same time but it's never really that. When people start replacing multiple parts to cure the same problem it is almost always because they haven't diagnosed it correctly.
It wouldn't be normal to start testing oil pressure when you have a cam timing/VCT issue (obviously this being PH someone will be along soon to say this would be the first thing they'd check). I don't know what the minimum pressure on your engine is for the VCT to operate correctly but I'd be very dubious about that diagnosis and need to look into it further.
It seems far more likely to me that they've messed up the phaser replacement (a tooth or so out on the timing on one cam) or something else is going on (dodgy solenoid etc.).
Surely low oil pressure would prevent the vvt from advancing the cam timing? Hardly an issue at idle. As you suggest, a mistimed cam seems more likley. Although this should throw a code.It wouldn't be normal to start testing oil pressure when you have a cam timing/VCT issue (obviously this being PH someone will be along soon to say this would be the first thing they'd check). I don't know what the minimum pressure on your engine is for the VCT to operate correctly but I'd be very dubious about that diagnosis and need to look into it further.
It seems far more likely to me that they've messed up the phaser replacement (a tooth or so out on the timing on one cam) or something else is going on (dodgy solenoid etc.).
Thanks both.
Garage said data logging showed the oil pressure was low only at hot idle. But, as they also said, it wasn't terribly low. I agree it does seem odd that the oil pump would go at the same time as the solenoid.
But, it did seem to drive ok when it was on the move, which wasn't the case before they had it.
Perhaps I need to dig deeper on this. I can't afford to just throw parts at it until fixed!
Garage said data logging showed the oil pressure was low only at hot idle. But, as they also said, it wasn't terribly low. I agree it does seem odd that the oil pump would go at the same time as the solenoid.
But, it did seem to drive ok when it was on the move, which wasn't the case before they had it.
Perhaps I need to dig deeper on this. I can't afford to just throw parts at it until fixed!
Edited by Rusty_ on Sunday 9th August 17:57
Grumbly said:
Surely low oil pressure would prevent the vvt from advancing the cam timing? Hardly an issue at idle. As you suggest, a mistimed cam seems more likley. Although this should throw a code.
I may have misunderstood your comment so apologies if this isn't what you meant...Yes, low oil pressure could easily prevent the VVT mechanism operating correctly. I don't know whether low oil pressure on this engine would do this before triggering a low pressure warning.
Hot idle is where oil pressure is at its lowest due to reduced viscosity and flow rate. It is also be the point where the cams are fully retarded and the mixture is lean. If the base timing is wrong this could potentially be where that is shown up.
I see your point about the timing code. You're right, I would expect this too. I'd be interested to see how this engine measures that and the ECUs strategy for detecting it.
Low oil pressure in general, or as a specific trigger for the variable cam timing not operating, logged in the diagnostics etc?
My (completely different) car uses small one-way valves in the oil passages through to the top end to hold some oil up top, so the cam timing solenoids don't have to wait for pressure to build.
If they get blocked or sticky, it can cause the car to see a problem with the variable timing, disengaging it and going into a safe default mode.
But they're not that expensive to replace.
Does your engine have something similar perhaps?
My (completely different) car uses small one-way valves in the oil passages through to the top end to hold some oil up top, so the cam timing solenoids don't have to wait for pressure to build.
If they get blocked or sticky, it can cause the car to see a problem with the variable timing, disengaging it and going into a safe default mode.
But they're not that expensive to replace.
Does your engine have something similar perhaps?
Rusty_ said:
Thanks both.
Garage said data logging showed the oil pressure was low only at hot idle. But, as they also said, it wasn't terribly low. I agree it does seem odd that the oil pump would go at the same time as the solenoid.
But, it did seem to drive ok when it was on the move, which wasn't the case before they had it.
Perhaps I need to dig deeper on this. I can't afford to just throw parts at it until fixed!
A few questions...Garage said data logging showed the oil pressure was low only at hot idle. But, as they also said, it wasn't terribly low. I agree it does seem odd that the oil pump would go at the same time as the solenoid.
But, it did seem to drive ok when it was on the move, which wasn't the case before they had it.
Perhaps I need to dig deeper on this. I can't afford to just throw parts at it until fixed!
Did they say how low? Do you know the target pressure and the pressure at idle?
Which engine is in your car and which cams have VVT?
At idle I would expect the cams' target position to be fully retarded. I would also expect the cams to return to this position if the pressure was too low to advance the phaser (not sure about this so happy if someone can explain why this would not be the case). With all this in mind I don't see how low oil pressure could cause the fault described at hot idle.
At idle I would expect the cams' target position to be fully retarded. I would also expect the cams to return to this position if the pressure was too low to advance the phaser (not sure about this so happy if someone can explain why this would not be the case). With all this in mind I don't see how low oil pressure could cause the fault described at hot idle.
[/quote]
Sorry if I wasn't clear, this is exactly what I was trying to say.
Thanks for the replies.
The engine is a 4.6 V8 3-valve SOHC. They didn't say what the target oil pressure was or what was measured, just that it was fairly low.
I'm not mechanically minded, but everything I am reading is suggesting the oil pump is probably not the culprit. Also, and this is the bit I'm flummoxed by - the car didn't have idle issues before. It idled and drove fine until the rough running/ choppiness developed all of a sudden. So, I'm effectively being told the oil pump has begun failing at the very same time as the VCT solenoid failed. That seems very unlikely?
I'm wondering if the timing could be off following the work they've done.
I've sent them an email explaining that I'm not happy at the whole saga, but I'm losing confidence that they know what the fix is!
The engine is a 4.6 V8 3-valve SOHC. They didn't say what the target oil pressure was or what was measured, just that it was fairly low.
I'm not mechanically minded, but everything I am reading is suggesting the oil pump is probably not the culprit. Also, and this is the bit I'm flummoxed by - the car didn't have idle issues before. It idled and drove fine until the rough running/ choppiness developed all of a sudden. So, I'm effectively being told the oil pump has begun failing at the very same time as the VCT solenoid failed. That seems very unlikely?
I'm wondering if the timing could be off following the work they've done.
I've sent them an email explaining that I'm not happy at the whole saga, but I'm losing confidence that they know what the fix is!
OP, have a chat with Adam at https://www.lmdautomotive.co.uk/
He has a wealth of knowledge on Mustangs and he always has at least 2 in his workshop for repairs or servicing,even owns his own '08 plate S197,hopefully he can help
He has a wealth of knowledge on Mustangs and he always has at least 2 in his workshop for repairs or servicing,even owns his own '08 plate S197,hopefully he can help
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