chrislangmd

Hi
I'm a complete newbie with regrds to the forum, and although this is my second CL it is the first 600 biturbo having had the CL55 before. I bought it practically unseen and it drove fine for 500 miles. Today I drove around 20 miles at a good speed and it was behaving beautifully. However, after parking for 30mins I came back to it and the second I put my foot on the accelerator to move off there was a loud whining which became louder and higher pitched the more I pressed the accelerator. There was also a marked loss of power. I can accelerate slowly to any speed on the motorway but as soon as I press the accelerator down past the bare minimum the whining comes back.
I think someone disconnected the 'check engine' light pre-purchse so it is off (as always even on turning key) and have not had the car checked with a code reader yet. Does anyone have an idea what this could be? I've heard that the turbos rarely fail and that coil packs always do eventually butI'd be interested in hearing peoples thoughts

Chris

Welwynnick

First thing to check is probably the sealing of the cast ally pipes from the turbos up to the intercoolers, and the big Y-tube from the intercoolers to the throttle body. Also check the integrity of the small pneumatic / vacuum pipes under the intakes that control the wastgates and divertor valves.

I think you may need to get a code reader; I can't imagine owning a V12TT without one.

Nick

chrislangmd

Nick
Thanks for your reply. Took it to a merc specialist who plugged it in, got misfires on left side as seen from inside car and he diagnosed coil pack failure . Other bank previously done. Sounded reasonable so we went ahead. Changed plugs too. Now no codes and engine fine but still whines on acceleration!! I told them to check the turbo stuff that you mention, and the serpentine belt pulleys which apparently can fail. Odd that've there are no codes now.

Chris

Welwynnick

You have to remove and refit the turbo outlet pipes in order to change the coil packs. Left for left and right for right. Sounds like that didn't make any difference, and you must have had more than one problem.

After the new coil pack, is it still not going right?

Does the engine warning light NEVER come on, even when you first start the car?

Can you hear the wining with the hood open and the engine idling?

Does the whine simply go up and down with the engine speed? How does gear-changing affect it?

Nick

biker349

ignition transformer?

chrislangmd

Thanks everyone for replies. Before the coil pck change the engine sounded fine and revved fine in park or neutral but when in gear and I accelerated even lightly I would hear the whine.
After reconnecting the power to the check engine light (!) it was lit but now off after replacing coil pack. Still whines on acceleration and if like before, major loss of power. All happened very suddenly 30 mins after parking up and coming back to car. I wonder if it is the auxiliary belt but I don't have a clue really

chrislangmd

Thanks Nick
At idle and in neutral/park the engine sounded fine BEFORE the coil pack replacement. When I accelerate at all I hear it and the pitch rises with increasing revs but sounds like very high rpm whine. Doesn't sound like an alternator noise to me.

Welwynnick

Could it be coming from the fuel pump, under the back seat?

chrislangmd

It is coming from under the bonnet in front of passenger side (uk). Definitely not back seat.

Welwynnick

The main things down there are the ABS and ABC pumps, but they won't cause power loss.

Are the brakes and suspension working normally with no warnings?

Whereabouts are you?

Nick

chrislangmd

Hi Everyone
Thanks again for helping. The most recent update from the mechanic is that, according to him, the noise is coming from the turbo although he says BOTH are broken. This is despite no error codes from the STAR. He says that I couldnt hear it before becuase one side wasn't working and now the coil pack is in that side works again hence the noise. I tried poitning out that the noise started suddenly one morning and was the reason I took it to him, and the coil pack had not been working for a long time already. Therefore, the noise has nothing to do with the faulty coil pack. Furthermore, the noise is very left sided when sitting in the car. Iti is only audible when the car is in gear and the throttle pressed more than a little bit. Changing gear manually doesnt seem to do anything to the noise, nor is it directly related to the revs, only to more than 10% pressure on the throttle.

I am disinclined to believe anything this guy says at the moment and can imagine replacing both turbos for 1000s and still having the noise 'cos its nothing to do with the turbo let alone both.

Any thoughts? There are no codes now and engine runs smooth at idle.

Chris

chrislangmd

Hi Nick
The brakes are fine and power steering fine. I occasionally get a white message re ABC but it goes out if I turn the car off and then on again. The only problem I noticed which started at the same time as the loud whining noise is that the fron parking sensors sometimes see things that arent there and beep inappropriately.

I am in Edinburgh, UK

chrislangmd

Turns out it was the turbo after all. Big hole in a vane. Had to lift the engine up to replace it. Expensive!

Welwynnick

Ouch. Sorry to hear about that. Doesn't happen very often.

Who did that for you? Did they say what caused the failure? There's usually a specific reason.

Nick

chrislangmd

A Merc specialist just west of Edinburgh fixed it. Came as a shock to him that he would have to lift the engine up to get it out. And to me for the labour costs! The other one needed an o ring replaced.
The inter cooler was completely dry which probably caused overheating I'm assuming. Hopefully I have haemorrhaged enough cash for now!

Are you based in the UK? Are you a Merc mechanic or an enthusiast?

Chris

Welwynnick

Yes, based in the UK, in Welwyn, of course!

I'm just an enthusiastic owner.

Nick

chrislangmd

Still had a droning hum in the car after turbo change. Changed the pulsation damper which is roughly under right front seat. A nightmare to undo the bolt without snapping valve block off mount but noise magically gone for £100. Found intercooler dry again and a bit of a whine which I think could be from dry water pump. Guess next thing is to find the leal!

s5benzo

How many miles on your 600 Chris ? Sorry to hear about the issues , when it rains it pours . Goodluck

chrislangmd

110k

I got it cheap and new it was a bit of a project. I've sored most now but still have a kind of pulley noise that is maybe fan relaed. There is a lot of inspiration to be found on the forum and am really grateful to everyone for the educational postings.

Chris

chrislangmd

Nick,
I have been thinking about my turbo failure and the fact there was little coolant in the intercooler circuit and wonder whether I have a IC PUMP FAILURE which I gather is very common. You seem to be an expert on the subject Nick. How can I tell if it's alive and pumping? Do I need to open a valve on the intercoolers up top or can I just listen to the pump down the front on the uk driver side with a mechanics stethoscope? What would you recommend? Also do you know if , is the Bosch pump ending with 10 easy to fit or do I need to adapt fittings or connectors?

Chris

Welwynnick

Hi Chris,

IC pumps are quite difficult to get a handle on, but have a significant impact on engine performance. However, I doubt a failed pump would lead to turbo failure - there are lots and lots of more likely explanations.

If the pump runs dry it WILL fail quickly, and I think small amounts of air in the system will shorten its life as well. The IC system is a pig to maintain, so it gets neglected, and the pump suffers accordingly.

There isn't a quick, easy and reliable way to test the pump. It only runs under load, so its difficult to prove whether it works when you're not driving fast. If you're very familiar with the V12TT, its all too obvious whether its working just by driving it, but that's not very objective.

The best way is probably to use an OBD2 reader to monitor intake air temps and see whether the IC appears to keep them under control or not.

Nick