Common Issues - Read this first
Posted: Mon Nov 17, 2008 8:38 am
edit: ive started adding some dephaser info.
edit : Added link to the workshop manuals and tech notes index
viewtopic.php?f=2&t=12790
Looking at the current list of topics today isn't it about time there was a "sticky" about these common issues;
The recent list is full of all the common issues that already been discussed many many times before;
Failing Pencil Coils
Petrol 1.4 / 1.6 / 2.0 ??
These are individual coils that provide the charge to the sparkplug. They are fitted to the top of each sparkplug and kept in place by a 10mm bolt.
Symtoms
A failed coil will mean the engine is firing on just 3 cyclinders and cause it to nearly stall and shake. It also may display the toxic fumes/engine mgmt light on the dash.
How to Test
see viewtopic.php?f=2&t=6200
How to Change
The coils work in pairs (the outside 2 and the inside 2)...and therefore i recommend at least a pair of coils is changed.This is probably one of the easiest jobs that an owner can do themselves.
To change a coil the engine must be cold, first unclip the connector by squeezing one end (like a peg) and pull towards you to release.using a 10mm socket unscrew the retaining bolt and pull the coil upwards to release from the sparkplug.
When refitting renualt recommend some special insulating grease (£40 for a small tube), so needless to say most people put new ones on without. when you refit the electrical connector you should hear a nice click.
repeat for the other in the pair or all others.job done.
tip: if you replace all 4 then throw away the bad pair and keep the good pair as spares.
Toxic Fume / Engine Mgmt Light
The dash light indicates an issue with the engine management...and is usually caused by one or more failed sensors or coils (for petrol) or glow plugs (for diesels)
1.6 vvt
nothing noticeably different with car only the light is on...cam sensor.
located right next to coil 4 (passenger side)..need to remove coil 4 for better access. easy to change. sometimes this just needs a clean. see viewtopic.php?f=2&t=7573&p=50936#p50936
1.6 / 1.4
car has trouble starting, stalling sometimes loss of power ...crank (TDC) sensor.
a bit more difficuly to change, located bottom of engine on top of the bell housing..new sensors from main dealer have a blue connector and requires some additonial wiring/connector (separate part) to connect to exisiting harness. black ones are the orignals which tend to fail.
generally once a fault has been rectified the light will go out after a number of journeys...sometimes the light needs to be erased by a computer or a special handheld tool. if using a tool, usually need to have the ignition on (but car not started) for the tool to erase codes - to turn on ignition put card in slot and press start button for 5 secs without pressing any pedals.
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.
Symtoms
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.
Issue
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 refils. It has also been suggested that the return spring is too weak to operate properly...so 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 sprocket...so very easy to knockout the timing, best left for a mechanic.
cost of dephaser part is £130....so with cambelt and labour it's going to be £350+ from a back street...up to double from a main dealer, a renault independant will be somewhere in the middle.
here's a link to a thread that explains the issue with pictures and advice on DIY viewtopic.php?f=2&t=8033&
Diesel Glow Plugs
see viewtopic.php?f=2&t=8224
Water Ingress
The megane is poorly water proofed...getting water into the electrics is a bad thing and will result in many different issues.
Problem areas are...
front doors...where the speakers are located water can get into the car result in water in the door and floor pockets and wet carpet.....The speakers need to be resealed in the door pocket or add a better inner door skin.
Symtoms
electrical failures and poor running seemingly unrelated to each other.... windows going down instead of up, auto lights not working...battery discharging itself...wipers not working etc etc.
Possible Cause
missing cover in the nearside wheel arch (for changing the headlight bulbs)..and water entering the UCH electrical unit.
ensure the cover is not missing and is well sealed..can be expensive if the UCH is corroded by water damage.
basically water & electrics don't mix.
"The PSU in your car became flooded with salt water. It is corrosive and dissolves printed board circuit (PCB) tracks and connector pins. If they are still intact and the failure is due to the leakage current, then the only escape is to remove the PSU, wash it with water, dry it at +60C (which is significantly lower than the limits of the components) and put it back. It would be also wise to remove the PCB and spray it with 3-5 layers of urethane." - source Alexb
see http://www.meganeownersclub.co.uk/forum/viewtopic.php?f=2&t=9939
Water in the engine fusebox, UCH, ECU...The fusebox lid is badly designed on early models and can let water in. This is fatal and can result in a new fusebox and drying out the ECU and other electrical bits..expensive.
Water can also lie in the bulkhead and you will hear the water "sloshing" when turning left/right...The water can make it's way thru the bulkhead into the cabin through cable holes...To resolve the drain in the bulk head will be blocked with dead leaves. see viewtopic.php?f=2&t=12727
Window Regulators/Motors
A very common failure is the windows to drop drown on their own. this is a failed window regulator. Again the most common reason is water getting into the inner door skins and into the electrics of the regulators/motors
Keycard Issues
the keycards are not very robust and can fail due to internal soldering drying out. See this guide on how to carefully prise apart the keycard and resolder the suspect parts.
viewtopic.php?f=2&t=13778
original post below.....
maybe it's because it's a wet monday morning... but i just can't be bothered posting the same reply info to the same issues that ive posted many times previously over the past 18 months. why don't people use the search facility ?
I don't think it would be too difficult to search and collate all the best nuggets of info on these and put them into one Sticky Topic.
worth the effort ?
edit : Added link to the workshop manuals and tech notes index
viewtopic.php?f=2&t=12790
Looking at the current list of topics today isn't it about time there was a "sticky" about these common issues;
The recent list is full of all the common issues that already been discussed many many times before;
Failing Pencil Coils
Petrol 1.4 / 1.6 / 2.0 ??
These are individual coils that provide the charge to the sparkplug. They are fitted to the top of each sparkplug and kept in place by a 10mm bolt.
Symtoms
A failed coil will mean the engine is firing on just 3 cyclinders and cause it to nearly stall and shake. It also may display the toxic fumes/engine mgmt light on the dash.
How to Test
see viewtopic.php?f=2&t=6200
How to Change
The coils work in pairs (the outside 2 and the inside 2)...and therefore i recommend at least a pair of coils is changed.This is probably one of the easiest jobs that an owner can do themselves.
To change a coil the engine must be cold, first unclip the connector by squeezing one end (like a peg) and pull towards you to release.using a 10mm socket unscrew the retaining bolt and pull the coil upwards to release from the sparkplug.
When refitting renualt recommend some special insulating grease (£40 for a small tube), so needless to say most people put new ones on without. when you refit the electrical connector you should hear a nice click.
repeat for the other in the pair or all others.job done.
tip: if you replace all 4 then throw away the bad pair and keep the good pair as spares.
Toxic Fume / Engine Mgmt Light
The dash light indicates an issue with the engine management...and is usually caused by one or more failed sensors or coils (for petrol) or glow plugs (for diesels)
1.6 vvt
nothing noticeably different with car only the light is on...cam sensor.
located right next to coil 4 (passenger side)..need to remove coil 4 for better access. easy to change. sometimes this just needs a clean. see viewtopic.php?f=2&t=7573&p=50936#p50936
1.6 / 1.4
car has trouble starting, stalling sometimes loss of power ...crank (TDC) sensor.
a bit more difficuly to change, located bottom of engine on top of the bell housing..new sensors from main dealer have a blue connector and requires some additonial wiring/connector (separate part) to connect to exisiting harness. black ones are the orignals which tend to fail.
generally once a fault has been rectified the light will go out after a number of journeys...sometimes the light needs to be erased by a computer or a special handheld tool. if using a tool, usually need to have the ignition on (but car not started) for the tool to erase codes - to turn on ignition put card in slot and press start button for 5 secs without pressing any pedals.
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.
Symtoms
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.
Issue
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 refils. It has also been suggested that the return spring is too weak to operate properly...so 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 sprocket...so very easy to knockout the timing, best left for a mechanic.
cost of dephaser part is £130....so with cambelt and labour it's going to be £350+ from a back street...up to double from a main dealer, a renault independant will be somewhere in the middle.
here's a link to a thread that explains the issue with pictures and advice on DIY viewtopic.php?f=2&t=8033&
Diesel Glow Plugs
see viewtopic.php?f=2&t=8224
Water Ingress
The megane is poorly water proofed...getting water into the electrics is a bad thing and will result in many different issues.
Problem areas are...
front doors...where the speakers are located water can get into the car result in water in the door and floor pockets and wet carpet.....The speakers need to be resealed in the door pocket or add a better inner door skin.
Symtoms
electrical failures and poor running seemingly unrelated to each other.... windows going down instead of up, auto lights not working...battery discharging itself...wipers not working etc etc.
Possible Cause
missing cover in the nearside wheel arch (for changing the headlight bulbs)..and water entering the UCH electrical unit.
ensure the cover is not missing and is well sealed..can be expensive if the UCH is corroded by water damage.
basically water & electrics don't mix.
"The PSU in your car became flooded with salt water. It is corrosive and dissolves printed board circuit (PCB) tracks and connector pins. If they are still intact and the failure is due to the leakage current, then the only escape is to remove the PSU, wash it with water, dry it at +60C (which is significantly lower than the limits of the components) and put it back. It would be also wise to remove the PCB and spray it with 3-5 layers of urethane." - source Alexb
see http://www.meganeownersclub.co.uk/forum/viewtopic.php?f=2&t=9939
Water in the engine fusebox, UCH, ECU...The fusebox lid is badly designed on early models and can let water in. This is fatal and can result in a new fusebox and drying out the ECU and other electrical bits..expensive.
Water can also lie in the bulkhead and you will hear the water "sloshing" when turning left/right...The water can make it's way thru the bulkhead into the cabin through cable holes...To resolve the drain in the bulk head will be blocked with dead leaves. see viewtopic.php?f=2&t=12727
Window Regulators/Motors
A very common failure is the windows to drop drown on their own. this is a failed window regulator. Again the most common reason is water getting into the inner door skins and into the electrics of the regulators/motors
Keycard Issues
the keycards are not very robust and can fail due to internal soldering drying out. See this guide on how to carefully prise apart the keycard and resolder the suspect parts.
viewtopic.php?f=2&t=13778
original post below.....
maybe it's because it's a wet monday morning... but i just can't be bothered posting the same reply info to the same issues that ive posted many times previously over the past 18 months. why don't people use the search facility ?
I don't think it would be too difficult to search and collate all the best nuggets of info on these and put them into one Sticky Topic.
worth the effort ?