Megane Starter Noise.

14 Jul 2012
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United Kingdom
I drive a 2004 Renault Megane 1.6 16 v VVT petrol 3 door hatchback manual and am experiencing a loud metallic clatter when starting from cold.the engine does not start but almost invariably will start at the second attempt.The car starts fine for the rest of the day.Problem only occurs first thing in the morning.It is a Keycard starting system.I am 84 years old and not able to do my own repairs but would like to know if this is a common fault before being conned into an expensive diagnostic check.How long can I safely continue with this "clatter" as the car runs beautifully once it`s started.? Thanks anticipation.
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That'd be your dephaser pulley. It is very common on Meganes of that model and age. No need to use a dealer though who will typically be twice the cost of an independent. This is shamelessly copied from the Megane owners Club Forum:

1.6 VVT Petrol Dephaser (mainly 2002 to 2005)
The dephaser is part of the ignition system that applies the "Variable Valve" technology. It alters the timing of the valves opening / closing to help efficiency.

On cold starts the engine will give an unmistakable grinding/rattle for a second..and probably stall straight away without actually starting. It may then start ok second time (without any noises) and run fine, as the problem gets worse you may need to give it plenty of revs to get it going.
not related to mileage...many examples of low mileage cars with the issue.
If buying a 2002 - 2006 car, this is one thing to check if the car has had a replacement...if not then factor into the price.

People who have opened up failed dephasers have found wear on the oil drain plug that is supposed to open/close...stopping it from closing completely and thus draining of oil. The noise is the drain plug trying to engage (at high speed) until the oil refills. It has also been suggested that the return spring is too weak to operate basically a manufacturing/design issue on early models (2002 - 2005)...
There has been many postings on this site over the years about this issue...and many have had repeated dephaser failures.

The part has now been redesigned a couple of times to overcome the issues...the latest version should be fitted to 2006 onwards, so in theory there should be few failures on 06 plates onwards (unless you know different ?)

How to Change
This is a skilled job and not really possibly for the home mechanic unless very experienced.
It requires locking the cams, changing the cambelt and removing the front cam very easy to knockout the timing, best left for a mechanic.
cost of dephaser part is £ with cambelt and labour it's going to be £350+ from a back street...up to double from a main dealer, a renault independent will be somewhere in the middle.

here's a link to a thread that explains the issue with pictures and advice on DIY[/i]

You need to be a member to read that thread (if you want to that is) but its free and easy to join the forum. Though if you type in 'megane dephaser problem' or similar into Google plenty more info will come up.
Why dephasers fail? My car does not have one, so everything below was investigated by somebody else. I hope it will be useful to some of us. I would like to thank the members of several public Forums quoted below for their in-depth research and photographs.

Exploded view is here:

This is the description by the manufacturer -- Delphi: ... train/vcp/

These are photographs of the dephaser: ... 679894.jpg ... 679937.jpg

This is the faulty dephaser taken apart, old model -- P/N 7701474362. ... 436198.jpg ... 436443.jpg ... 436449.jpg ... 436445.jpg ... 437432.jpg ... 437433.jpg
It rattles as the locking pin stops doing its job. One can also see wear of the components. This is an example of a damaged locking pin: ... 067121.jpg

This is the intermediate edition of dephaser, P/N 7701478079. The same design, metal filings discovered inside the new part...

The third (currently the latest) reincarnation of the same part, P/N 7701478505. The same design, the pin is probably improved. ... 095427.jpg ... 095428.jpg ... 095429.jpg ... 095430.jpg ... 095433.jpg ... 095431.jpg

These came from this source: ... topic=7022
Some work including modifications to the dephaser was done here (author Mishgan): ... 5396&st=40

One of authors of this research MegaMike from the above forum discovered that the cause of the problem is excessive wear causing increased axial play (more that 0.15mm) and, as a result, oil leaking away from the dephaser back in the sump. However, the other failed dephaser had a small axial play, but the plastic flat seals were faulty... In addition, the locking pin alone appears to be unable to hold the load. It has a conical surface loaded with a side force. A projection of this force pushes the pin out of the hole. A simple calculation shows that the strength of the return spring is insufficient given a very high strength of valve springs (valve springs have to be strong to work at high revs) creating high torque on the camshaft. When a dephaser is not worn and is filled with oil this problem is not noticeable, but when it is dry then a scary rattle appears. There were 3 part numbers released, which is an indication that Renault and Delphi are well aware of the problem!

Here one can find a detailed analysis of the design fault, it is in a wrong language for most of us: ... ntry118155
To summarise, the design of conical surface of the locking pin and the return spring is not good, which includes geometry, choice of materials and the strength of the return spring. As a result the locking pin is bound to stop performing its function at some stage. It is a "joint" fault of Delphi, who supplies dephasers, and Renault, who did not test this part sufficiently well. An option is that testing was done on a prototype engine before it was enhanced by using "racing" style hard springs and cams with roller rockers.

This is an overview of dephasers:

Renault discusses this problem in their technical note TN4432A.

This is it, I guess. The problem is down to lubrication failure and poor design by Delphi. It makes me think about possible use of special oils having extreme pressure properties, such as VW PD 505.01 (e.g. see Fuchs and Motul range at, or ester-based racing lubricants as a "patch" to the problem, and someone reported using Mobil 1 5w-50 oil with a great deal of success. I wonder if the recently introduced RN0700 oil specification will help to keep dephasers alive until the big service...

A funny finding: Delphi reduced weight of this part by 30-40% by using aluminium. Was it a good idea? ... 961&EDATE=

The rumours that the latest version of dephaser includes a return valve are not true (see the photographs above). There are very minor modifications to the lock pin and the return spring.
Would an oil additive be of any help, probably gone past the point of rescue?
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Thank you very much for your detailed reply to my problem.How long do you think I can safely live with this problem.I only do about 5,000 miles a year ,mostly short trips.I have only had this car for 4 months ,but am concerned it could be a very expensive purchase re spare parts etc.? Am tempted to get rid .
I believe likely symptoms to occur (if not already evident) are likely to be poor running especially when pulling away in first, stalling on startup, uneven idling. Really surprised you're not getting any of these already. I'd guess you can live with it until it drives you up the wall so to speak. Meganes especially earlier ones had many a problem the dephaser amongst them. By 2006 they were getting better though. Expect your front windows to go wrong every now and then that's a pretty common (I've had 3 go wrong :rolleyes: ). Really though I would say all cars have their problems depends if you like it or not. I have a love hate relationship with mine. If you want reliability above everything else though Japanese was the way to go no French.

Mursal when the grinding starts its too late for decent oil the damage is done.
Thanks again for reply. Not having problems Re poor running ....yet,but it will no doubt deteriorate .As I said in original post I am 84 and am afraid my pension wont run to expensive Renault repairs.I was looking for an everyday runabout when I bought it as my old Rover (14 years old) had failed it`s M.O.T and the Megane looked very attractive and was in my price range. I know all used cars are a gamble but I need something that will keep me mobile without causing too much worry over being able to afford to keep it on the road.
it will gradually get worse as said and the car will be difficult to drive eventually.
horrible cars sadly, my honest advice would be to get rid of it and buy something more reliable.
Thanks a lot for your help, I guess it will have to go although I`m not looking forward to dealing with used car salesmen again.....Cheers..thanks again.
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