Advice sought
Author
Discussion

Rusty_

Original Poster:

150 posts

108 months

Sunday 9th August
quotequote all
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!

Edited by Rusty_ on Sunday 9th August 15:19

Richard-D

2,160 posts

92 months

Sunday 9th August
quotequote all
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.).

Grumbly

331 posts

176 months

Sunday 9th August
quotequote all
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.

Rusty_

Original Poster:

150 posts

108 months

Sunday 9th August
quotequote all
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!

Edited by Rusty_ on Sunday 9th August 17:57

Richard-D

2,160 posts

92 months

Sunday 9th August
quotequote all
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.

InitialDave

15,040 posts

147 months

Sunday 9th August
quotequote all
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?

Richard-D

2,160 posts

92 months

Sunday 9th August
quotequote all
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...

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.

Grumbly

331 posts

176 months

Monday 10th August
quotequote all


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.

Rusty_

Original Poster:

150 posts

108 months

Monday 10th August
quotequote all
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!

Saleen836

12,466 posts

237 months

Monday 10th August
quotequote all
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

DodgyGeezer

48,572 posts

218 months

Monday 10th August
quotequote all
this chappy had a sterling rep in my S197 days; it may well be worth a chat with him?

https://www.modurstang.co.uk/

CoolHands

23,214 posts

223 months

Monday 10th August
quotequote all
Don’t know about that engine but mine also has a solenoid on the oil pump. I had problems, replaced cam phasers and vvt soelenoids on the camshafts, still problem. Eventually figured out the oil pump vvt solenoid was causing all the problems.

So, in short, does your oil pump also have a solenoid as it could be that.

Rusty_

Original Poster:

150 posts

108 months

Tuesday 11th August
quotequote all
Thanks - I don't think it does have a solenoid on the pump itself, although I might be wrong.

Thanks for the recommendations. I was originally going to use Adam at LMD Automotive, but he's some distance from me and recovery would have cost a fortune.

Yesterday I was told the car was on the ramp getting the additional work done and they'd call me this morning with an update. No call. Also, I was quite surprised that they didn't plan/offer to replace the timing components (guides, tensioners, etc) while the timing case was off. I've asked them to double-check to condition of it all.

Hopefully they come back with an update soon. I wouldn't be surprised if this new oil pump has made no difference, hence lack of a call. Perhaps I'm being cynical.

Edited by Rusty_ on Thursday 13th August 15:08

Saleen836

12,466 posts

237 months

Tuesday 11th August
quotequote all
DodgyGeezer said:
this chappy had a sterling rep in my S197 days; it may well be worth a chat with him?

https://www.modurstang.co.uk/
Modurstang has a new owner and have heard service has dropped

Rusty_

Original Poster:

150 posts

108 months

Tuesday 11th August
quotequote all
That's right. The previous chap is now retired I think.

I'm going to have to call in the morning, again, and ask what's going on now. It really shouldn't be this painful and I'm getting royally pissed off at it all now!

Saleen836

12,466 posts

237 months

Tuesday 11th August
quotequote all
Rusty_ said:
That's right. The previous chap is now retired I think.

I'm going to have to call in the morning, again, and ask what's going on now. It really shouldn't be this painful and I'm getting royally pissed off at it all now!
Yes, the previous owner who started the business now takes his mustang to Adam (LMD) hehe

Rusty_

Original Poster:

150 posts

108 months

Tuesday 11th August
quotequote all
Surely not! You're joking hehe

Saleen836

12,466 posts

237 months

Tuesday 11th August
quotequote all
Rusty_ said:
Surely not! You're joking hehe
100% not joking

Rusty_

Original Poster:

150 posts

108 months

Tuesday 11th August
quotequote all
Oh dear.. That's not a good sign!

DodgyGeezer

48,572 posts

218 months

Tuesday 11th August
quotequote all
Saleen836 said:
Rusty_ said:
Surely not! You're joking hehe
100% not joking
yikes