Esprit S4 Engine rattle/noise/tapping

[AdamDE]

Hi all,

 

I hope you can help... I'm trying to pin-point the source of a horrid/annoying noise that developed with my S4 after about 300 miles of owning it. It went away for a while and became intermittent but it's there most of the time now. I could start the car, drive to work and there would be no noise. Then start the car to leave work and the noise would be there. On a long journey there will still be some time when the noise isn't there. So:

• Car had a C-Service 300 miles before noise started (New belts etc...)
• Doesn't seem to be temperature related. Happens when first started and when hot.
• Does increase with revs (rattle seems to get quicker).
• Seems to come from front of engine (belt area) and more toward the bottom.
• Charge Cooler impeller most likely nackered (it's warm/hot to touch)
• Oil pressure gauge is a bit 'erratic' but I believe it's done that since the start, along with the fuel gauge depending on how full it is)

The car has actually done another 1000 miles since it started (as it had to get to Germany) and is going into Lotus in 2 weeks, but I'd like to see if I can find the fault before then (maybe source some parts!). I've tried getting freescan/espritmon to work to help diagnose it but I've had no luck with that yet.

 

I have a Stethoscope. I 'probed' various upper engine parts that I could reach, the top of the engine sounded fine to my untrained ears (perhaps I can create a video with stethoscope sounds another day) where the spark plugs are etc, turbo sounds okay etc. The only place I seemed to get some noise was the water pipe that's above the alternator. Although, another time it didn't seem to come from there either!

 

Any suggestions?

 

I've managed to upload some videos after a nice long run. When the car was initially started up there was no noise, but then it came back so I got the phone out:

[Sparky]

Really difficult to say, but I'd first be looking at the water pump and power steering pulleys to see if there's any play there.  Even in the short videos, the sound is erratic enough to imply it's not engine internal - but don't take my word for it!

 

Also, check the power steering pump bracket - they're known to work loose or fracture.

[AdamDE]

Here's an audio track I've managed to convert to a video, just so I can upload it, from a different time:

 

 

(First starting above the engine and then underneath)

Really difficult to say, but I'd first be looking at the water pump and power steering pulleys to see if there's any play there.  Even in the short videos, the sound is erratic enough to imply it's not engine internal - but don't take my word for it!

 

Also, check the power steering pump bracket - they're known to work loose or fracture.

 

I'll have a look at which pump is which and try to get under the car again soon, not got much space to work with.

I certainly hope it's not the internal engine, although I believe the water pump is also costly to replace and I half suspected it could be that myself.

[Sparky]

That does sound like the steering pump bracket...

[glynherron]

My power steering pump bracket had an Allen bolt which worked lose. It couldn't drop completely out as it couldn't clear the power steering pulley. The head of the bolt just jostled along the pulley and made an awful scarey noise. Simple fix but had to shorten the short length of an Allen key to fit in the gap. Fingers crossed.

[mr.oogieboogie]

Yep had this on mine sailorbob and i found it. Put some thread lock on it otherwise it will return.

[iainskea]

Awful sound Adam, hope you have found it. As an aside, great video of the car - looking magnificent against the countryside background. Iain

[Vulcan Grey]

It sounds similar, though lower in tone, to when you have a connection open to the intake manifold.

 

If you have a split in one of the barb fittings for the vacuum purge line, or the pressure tap for the fuel pressure regulator, then it'll sound a bit like that.  A lot of intake cam chatter.  I'd say look for air leaks to the intake manifold.

 

But also keep your eye out for more serious issues.

[AdamDE]

Thanks for your suggestions so far. At least I've learnt it's not easy to reach or find the Steering Pump without a ramp or lift (I'll try and jack it up at the weekend to get more room). I gave up feeling around for it after I realised it was behind a plate and my arms weren't long enough to grab hold of it to test if there's any play or not. I managed to find it with the help of a phone/with light. I don't know if these videos of the belts help any further, I was taking them blind:

 

[Vulcan Grey]

great video.

 

Tough to tell, the noise seems louder when the camera is pointed towards the sump or left.  Not so much the power steering pump.

 

You could try removing each of the belts at a time to see if it is from the alternator, AC or the water+PAS pumps...

 

The other possibility is that the alternator plastic bracket can often rub on the AC belt or pulley...

[mr.oogieboogie]

Get the car up undertray off. Losen the locking bolt on the pas pump. May need to bend the heat shield. Loosen off the pas tensioner nut

Take off the belt. Get a small rachet undo the pully wheel there is a bolt behind there. Check it. Also there is another bolt behind the heatdhield. I had the cast on my pas pump snap and only the locking bolt and the bolt behind the heat shield were holding it on.its a bit tight but can be done approx 1hr start to finish

[AdamDE]

So I've got the car up and it seems like the noise is actually coming from the pulley at the end of the crank shaft, the pulley gear that has the 3 aux belts attached to it is clearly shaking/wobbling. There's a nut on the end of that, doesn't feel loose by hand. Is there a certain torque this should be set to?

[AdamDE]

As for the power steering pump, it doesn't appear to be making any noise, and I can't move it at all. However, the adjuster at the front is completely loose. There also appears to be a nut/bolt missing I think.

[Vulcan Grey]

So I've got the car up and it seems like the noise is actually coming from the pulley at the end of the crank shaft, the pulley gear that has the 3 aux belts attached to it is clearly shaking/wobbling. There's a nut on the end of that, doesn't feel loose by hand. Is there a certain torque this should be set to?

 

Cranks pulley bolt torque is 58-60ft-lb (79-81 Nm).

 

As for the power steering pump, it doesn't appear to be making any noise, and I can't move it at all. However, the adjuster at the front is completely loose. There also appears to be a nut/bolt missing I think.

 

Looking at the parts manual (since I don't have power steering) that appears to be correct.  There is no nut on the other side, since that is a jack-screw for pushing the pump body away from that bracket in order to tension the belt.

[AdamDE]

Thanks. Managed to find the torque amount just before. I've checked it and torqued it clockwise to that amount and the cog/pulley still twists when I pull each belt in turn.

[Sparky]

When you say 'twists', do you mean that you can wobble the crank pulley by hand after ensuring the bolt is tight?  That's supposed to be a snug fit even without a bolt in it.  If that's the case I wouldn't be running it - I'd have that pulley off to see what the mating faces look like.

[fflyingdog]

I'm not 100% sure but shouldn't that pulley have a locating spline/ peg/woodruff type thing? Also the adjuster on the PAS pump should be pretty firm does your pump screech when putting a demand on it?

 

 Nick S4s

Edited May 17, 2014 by fflyingdog

[CHANGES]

I hate  to say this Adam, but that sounds awfully like a bottom end noise to me..

I would have it a guess its the big ends badly worn. If i am correct this will get a lot

worse and very quickly.

Personally i would be pulling it out for a rebuild...  If you want to do a provisional

check you can slip the sump off to check the big ends before pulling it.

When big ends are on the way out you may not have major oil pressure fluctuation,

but there will be signs if you know what to look for..

If you carry on running it like this and it is the ends then you could damage the crank

beyond repair, as they can only go .020 max on a grind..

Its difficult to fully asses off a video with so many things to consider. But i really don't

like the sound of that.  

If you want to talk one to one , PM me and i will send you my phone number..

 

Dave (Changes) 

 

 

[ramjet]

Are you able to get a video of what you mean by the crank pulley twisting? As Sparky said, it should be a snug wiggle free fit even without the clamp bolt.

I thought that the noise was more prominent when you were facing the PAS pump. Might have just been me.

[fflyingdog]

I don't want to be the harbinger of doom but unfortunately I have to agree with Dave it does indeed sound terminal and probably not wise to carry on running until you find out conclusively what the noise is.You could try disconnecting all the ancillaries and just leave the cam belt and see if the noise disappears but I rather think it wont.It does sound like a bag of spanners to be honest and I think Daves idea is probably the best .

 

Nick S4s

[jimblob]

Didn't you just buy this from a dealer? does it have any warranty? 

[Chillidoggy]

Has it got air-conditioning? Because it sounds it could be an A/C pump rattle to me. Belt-related, whatever the belts drive on the engine (I've no idea). I'd be inclined to disconnect whatever belt I could get away with, run the engine and see the noise disappears before I did anything else. In my experience, bottom-end failure noise is usually deeper than what I can hear on the videos, though.

 

But, whilst I am an engineer, I am also a complete Lotus virgin, hence I could well be talking rubbish. Which is not unknown.

[AdamDE]

Are you able to get a video of what you mean by the crank pulley twisting? As Sparky said, it should be a snug wiggle free fit even without the clamp bolt.

I thought that the noise was more prominent when you were facing the PAS pump. Might have just been me.

 

Yes I took a video and will try and upload it. It appears that the main crank sprocket itself is solid, just that the auxiliary pulley feels loose even when the nut is tightened.

 

 

 

Didn't you just buy this from a dealer? does it have any warranty? 

 

Yes but unfortunately the dealer is in another country and 600 miles away, so it's not really viable to go down that route (yet).

 

Has it got air-conditioning? Because it sounds it could be an A/C pump rattle to me. Belt-related, whatever the belts drive on the engine (I've no idea). I'd be inclined to disconnect whatever belt I could get away with, run the engine and see the noise disappears before I did anything else. In my experience, bottom-end failure noise is usually deeper than what I can hear on the videos, though.

 

But, whilst I am an engineer, I am also a complete Lotus virgin, hence I could well be talking rubbish. Which is not unknown.

 

Yes it has got air-conditioning. I had the bottom-end go on an old Saab and it did sound a lot deeper than this does, but I can't rule it out. 

 

When under load the power steering pump doesn't squeal or make any additional noises and generally feels solid. I tightened up the adjuster just enough to prevent if from rattling in case it was just that.

 

So the worst case is I need a rebuild... does anybody want to throw a rough estimate of the kind of money one costs? I can then let my bank manager know she can crack open the champagne.

 

It's in for a Lotus inspection in a week, so I'll get them to take all the belts off, followed by the sump if the noise is unchanged. I doubt I'll get chance to attempt that myself between now and then.

[fflyingdog]

Surely it shouldn't be your bank manager opening the champagne? Can you not just trailer the car back to where you bought it and get them to fix it?

 

whats your oil pressure looking like ? If you do have a impending bottom end failure I really wouldn't run the car could make things a lot worse.You don't want the dealer saying anything that could infer you made matters worse.

Edited May 18, 2014 by fflyingdog

[Chillidoggy]

I watched your videos, and I can't imagine why a V-drive pulley should have any of that kind of movement on it at all. Requires further investigation, that one!