Renault Megane Cylinder Compression Problem

[yilonur]

Hi Everyone,
This is my first post and I am new here.
I have a question about my 2015 Renault Megane GT Premium.
My car had an ESC warning about a month ago and I got a mobile mechanic to check my spark plugs ang coils. They were both changed but I still had the ESC warning and engine was shaking a bit with not much limited power. The mobile mechanic said it might be because of a bad fuel (my last fuel was from Metro and I used them for the first time after 5 years) so I decided to wait and driven the car around the house for a while to check but no luck.
Finally, I took it to a proper mechanic. My mechanic's diagnosis is that my 3rd cylinder is not working. He is giving me 2 options;
1) change the entire engine which would cost around $10K
2) strip down the top of the motor and check what part might be causing the problem on 3rd cylinder. He said this might cost around $5K
So either way, its a costly repair and I am thinking whether this is worth it or not as I bought the car back in 2019 for $8.8K. It's a good car with leather seats, great fuel economy with lots of features but I dont want to spend more than the price of the car. I am thinking of taking the car to maybe another mechanic to get a secondary view but not sure if this will change anything.

I am seeking your advice here.
1) Has anyone else had a similar problem before ? Is there a cheaper fix that you can recommend.
2) What do you guys think about getting the car to another mechanic ? Maybe towed it to Renault service ?
3) Any chance this might be related to bad fuel ?

If I am not getting the car fixed, my only option is to sell it as is to unwanted cars and maybe recover $1K (at best). I really want to get the car fixed but at a financially viable way. Any advice is welcome.

Thanks in advance!

 

[seasink]

my 3rd cylinder is not working

That's vague for sensible discussion. From that misfire, the fault may be an injector, or a spark plug/coil. or loss of compression, which could be rings or head gasket. Some of these are indeed expensive. Do you have any OBD fault codes, or a compression reading?

By ESC do you mean steering and brake stability control (aka ESP) ? This isn't a cylinder misfire fault.

Welcome to the forum.

 

[COL]

Welcome to Aussiefrogs Yilonur.

I think you need a bit more diagnosis to what the problem actually is.

What engine do you have in the car? Is your Megane the GT Line or a GT220?

The mechanics that have had a look at the car have obviously put an OBD scanner on the car and got codes from it, is it possible for you to tell us what those codes are. This will tell us if something is wrong with a sensor, ignition coil or maybe injector.

When you have got the codes and had a look at what they are telling you and replacing those parts and this does not fix the problem, it is then time to look a little deeper into the internals of the engine. There are two checks that can be performed. #1 a compression test done both dry and wet of all cylinders to see what the result is. #2 a leak down test where compressed air it put into the cylinder via the spark plug hole with each cylinder is on top dead centre.

If you mention these test to your/the mechanic and they don't know what they are or refuse to do them walk away and find a mechanic that does.

When you have the results from these tests you can then decide what the best course of action will be.

 

[jaahn]

These answers are a good start. But I would say we do need to know what engine you have. The VIN would be good if you are not sure or the information on the stickers, on a lower door door pillar probably.
Do not rush into a vague guess at the problem. You can get a parts place like Repco or Supercheap to read the codes with a scanner for a modest charge if you do not know what they were. Tell them DO NOT CLEAR THE CODES. JUST READ THEM FIRST AND WRITE THEM ALL DOWN. Then you can clear them and see if things improve. There is more data available to a good mechanic with a professional scanner about misfiring etc and the cylinder involved.
Never rush into pulling things apart or trying to fix a car until you know what is wrong with it and have proved it by specific testing.
Good luck jaahn

 

[yilonur]

Thanks a lot for your responses @seasink @COL @jaahn

@seasink I cant exactly remember the OBD fault code but the first mechanic concluded that it was related to spark plugs and ignition coils both of which are now replaced with brand new ones but the issue is not resolved. The current mechanic concluded that the issue is on he 3rd cylinder which gives "0" compression. By ESC I mean "check ESC" error on dashboard. When I googled it, I realized its quite common and can mean lots of different issues with the car but the mechanic put the scanner and told me it was about coils and ignition.

@COL my car is Renault Megane GT Premium 2015 model. I should have asked the OBD codes but I didnt. I might go and ask that again but I am somewhat confident that what the mechanic is telling me about the cylinder compression is true. Noted your advice on asking the mechanic on the tests.

@jaahn the VIN number is: VF1BZ3603F0718556. Thanks for your advice on the codes. I'll ask and note the error codes down. As I said, I am somewhat confident that the issue is related to the cylinders. The decisions I need to take now are 1) should I take the car to another mechanic ? 2) should ask for a repair with current mechanic 3) should I go for a full engine swap (which makes no financial sense).

My mechanic is a good one with strong reviews and he is a local in the area. I am not entirely sure though if he is willing to fix my car as its a relatively cheap car. He is probable prioritizing other fancy cars in the shop. Hence I am thinking of maybe dropping the car to another mechanic.

Once again, thanks a lot for your responses. Any further advice based on above is much appreciated.

 

[petermelb]

looking at it from a financial point of view, it cost you 8.8k 5 years ago, if you take the cost of owning a car (how much to have it sitting in your driveway, mostly depreciation) at 1,000 a year, the car owes you say 3k, if you look at newer cars, the cost is much more, so basically you have had your 8.8k use out of the car.
Then you have to decide if the repair cost, you mention 5k above, is worth it, or what else you can buy for 5k, and if it turns out to be 10k, then for sure you can buy some resonably nice cars for 10k.
so the first step is to pin down exactly whats wrong with it, as mentioned above a compression test would show up any mechanical failure. If the compression is ok, it should be relatively easy to fix, if low compression and head needs to come off to fix valves or pistions, i would be looking for alternatives.

 

[seasink]

A simple compression test can be done by any mechanic. If you have no compression at all then you are up for major dismantling,and the car would be undriveable.

When the codes were read for misfiring the particular cylinder should have been indicated, and the usual test for plugs and coils is to swap them with another cylinder and see if the code fault moves to it. Low compression will not move. So plug/coil problems can be diagnosed easily.

Where are you located in Sydney? There are mechanics who like Renaults, eg https://www.colliersauto.com.au, and members may suggest others.

 

[yilonur]

thanks @petermelb . As mentioned, the compression test has been completed and my 3rd cylinder has 0 compression. Other cylinders are OK. I agree with your financial reco and not willing to go down the path of changing the entire engine.

Do you guys think that calling another mechanic and explaining the issue on the phone and asking if they are willing to fix it at a reasonable cost would be an option ?

 

[yilonur]

@seasink the compression test has been completed and the 3rd cylinder was identified as the problem with 0 compression. Plugs and coils were changed already but not sure if they did the swaps.

Yes I am located in Sydney and will give a call to colliersauto. thanks heaps!

 

[JoBo]

I'd still do a leak down test to see if it's a lower problem or an upper problem. If it's upper, a second hand head or even a repair might be the cheapest way to solve the problem

 

[jaahn]

thanks @petermelb . As mentioned, the compression test has been completed and my 3rd cylinder has 0 compression. Other cylinders are OK. I agree with your financial reco and not willing to go down the path of changing the entire engine.

Do you guys think that calling another mechanic and explaining the issue on the phone and asking if they are willing to fix it at a reasonable cost would be an option ?

yilonur your question is difficult to answer quickly. The ESC warning would not normally be related to any engine problem. It indicates a problem with the safety brake and stability controls but will not affect the engine performance directly.

Then the first mechanic put a scanner on the engine and for unknown reasons diagnosed the plugs and coils needed replacing ?? That is a puzzle and it did not solve the problem either. That seems like incompetence. What did he say then ?

Then the second mechanic looked at it and did a compression test and found #3 had 0. Seems like the problem. (Still not connected to ESC) The problem might be the gasket, valves or the rings or piston. It is not possible to know without some normal testing by an experienced mechanic. If the gasket or valves, then removing the head and repairing as necessary would fix it for a medium cost. If the rings or piston then more expensive.

Get a mechanic who wants to work on Renaults and can do a complex job properly, and get some quotes. It is possible that a complete engine from a wrecker and fitted might be a good option as the labour cost might be lower than fixing it. So get a price for that option by ringing wreckers also.
Jaahn

 

[Armidillo]

yilonur your question is difficult to answer quickly. The ESC warning would not normally be related to any engine problem. It indicates a problem with the safety brake and stability controls but will not affect the engine performance directly.

...
Jaahn

I would have said exactly the same until this year...

We now own a (diesel) Ford Territory. Earlier this year we got a DSC (Dynamic Stability Control) error, and the engine went into limp mode. Cause was a faulty EGR valve (it has 2, but have only replaced the one, so now waiting for the other one to fail ).

Apparently the stability control computer gets priority for message display. If there's an engine problem, the ESC/ESP/DSC computer won't be able to control the engine the way it wants to in an "emergency" situation, so it warns you and vacates the field. This video goes through the 3 most likely cause of the DSC error msg:

We also got the Engine management fault, but nothing more specific. Of course when I took it to a mechanic, it "fixed" itself - took several days to get it to play up at a time the mechanic could scan for codes and observe the behaviour.

 

[COL]

thanks @petermelb . As mentioned, the compression test has been completed and my 3rd cylinder has 0 compression. Other cylinders are OK. I agree with your financial reco and not willing to go down the path of changing the entire engine.

Do you guys think that calling another mechanic and explaining the issue on the phone and asking if they are willing to fix it at a reasonable cost would be an option ?

So the mechanic has done a compression test and found there is no compression on #3 cylinder. The next test to do is a leak down test so that you can work out what has failed to cause no compression.

A leak down test will tell you exactly where the failure is such as inlet valves, exhaust valves, head gasket, rings etc. With zero compression doing the leak down test it should be pretty easy to tell where the problem lays.

Once you have this information you can then decide and what action to take.

Spending a few thousand dollars on repairing what is otherwise a good car in not really much in the scheme of things. You can purchase another car and can have the same issues with it as well, we don't have crystal balls and have to make decisions on the facts at hand at the time, that is why it is very important to spend some time and money doing a proper diagnosis so that the right decision can be made.

 

[COL]

When the codes were read for misfiring the particular cylinder should have been indicated, and the usual test for plugs and coils is to swap them with another cylinder and see if the code fault moves to it. Low compression will not move. So plug/coil problems can be diagnosed easily.

I have had misfiring issues on Laguna V6 with no fault codes numerous times. The codes will show up if the fault is on the primary side of the coil. If the fault is on the secondary side there seams to be no fault code.

I have found out which cylinder is the issue by doing the old fashioned disconnect of the coil on that cylinder to see if the revs drop or not.

 

[Bowen]

Seconded on the leak down test, and a mechanic that knows how to do one! I'm always surprised by stories of mechanics that repeatedly misdiagnose cars when a leak down test would have shown the issue quite quickly.
If you have the time/ability/means:
Zero compression is a fairly serious hole for air to escape the cylinder. Injector popped out or seal blown maybe? With such a large leak, you could get away without a proper leak down tool with gauges etc, just connect an air source to the plug hole with the engine on tdc for that cylinder. Could use a rubber grommet of some kind and you should be able to hear where the air is rushing out.

You can also buy fairly cheaply inspection cameras, which would let you see into the plug hole with the spark plug removed if the inside of that cylinder is destroyed (dropped valve or some mechanical mayhem) which if there is you can then call the engine dead).

 

[yilonur]

Thanks @COL I will ask and insist on the leak down test from my mechanic. I am also in favor of getting the car fixed at a reasonable cost if possible.
Thanks everyone. I will update you all after getting an update from my mechanic.

 

[yilonur]

yilonur your question is difficult to answer quickly. The ESC warning would not normally be related to any engine problem. It indicates a problem with the safety brake and stability controls but will not affect the engine performance directly.

Then the first mechanic put a scanner on the engine and for unknown reasons diagnosed the plugs and coils needed replacing ?? That is a puzzle and it did not solve the problem either. That seems like incompetence. What did he say then ?

Then the second mechanic looked at it and did a compression test and found #3 had 0. Seems like the problem. (Still not connected to ESC) The problem might be the gasket, valves or the rings or piston. It is not possible to know without some normal testing by an experienced mechanic. If the gasket or valves, then removing the head and repairing as necessary would fix it for a medium cost. If the rings or piston then more expensive.

Get a mechanic who wants to work on Renaults and can do a complex job properly, and get some quotes. It is possible that a complete engine from a wrecker and fitted might be a good option as the labour cost might be lower than fixing it. So get a price for that option by ringing wreckers also.
Jaahn

@jaahn the first mechanic was a mobile one and based on the OBD he thought it was coils/spark plugs therefore changed them. After changing them the issue continued and his assessment was that the car needs to be lifted to have a proper check. he also pointed to a potential bad fuel issue. anyways, I agree he wasn't the most competent one.

second mechanic is now waiting for quotes of a wrecked engine. If he can find a reasonably priced one, he is keen to change the entire engine because its less labour extensive and also the engine comes with a warranty. its obviously much more costly. Once that option is exhausted we will discuss the potential repair path and the tests etc. So far, I am OK with this approach as I dont need the car and happy to wait a little longer.

At this stage, I am not willing to spend more than $3-4K for this car. its in a good condition otherwise but I have to be financially prudent. If he cant find an engine and the car needs a repair I will most likely go ahead with another mechanic who is more willing to work on this. then I have towing cost etc. I think its best for me to go step by step at this stage.

 

[Bowen]

@jaahn the first mechanic was a mobile one and based on the OBD he thought it was coils/spark plugs therefore changed them. After changing them the issue continued and his assessment was that the car needs to be lifted to have a proper check. he also pointed to a potential bad fuel issue. anyways, I agree he wasn't the most competent one.

second mechanic is now waiting for quotes of a wrecked engine. If he can find a reasonably priced one, he is keen to change the entire engine because its less labour extensive and also the engine comes with a warranty. its obviously much more costly. Once that option is exhausted we will discuss the potential repair path and the tests etc. So far, I am OK with this approach as I dont need the car and happy to wait a little longer.

At this stage, I am not willing to spend more than $3-4K for this car. its in a good condition otherwise but I have to be financially prudent. If he cant find an engine and the car needs a repair I will most likely go ahead with another mechanic who is more willing to work on this. then I have towing cost etc. I think its best for me to go step by step at this stage.

Obviously you need to do what is right for you, but this sounds a little backwards to me based on what you have provided in the thread so far. Tests should be done first. Surely there is only about 1 hour labour for a leak down test to most likely confirm where your issue lies. No doubt an entire engine swap will fix whatever issue you have, and I guess you need to factor in the k's on the current unit which you haven't mentioned. I know it's tricky when you have cost after cost including towing to a different mechanic. I wish you all the best! If they swap the engine, make sure you keep a hold of those brand new coils and plugs!

 

[yilonur]

the car has high mileage relative to its age. it has approximately 140K. thanks for the advice. will definitely ask the leak test and understand why they haven't done it yet. my theory (I might be too naïve) is that the mechanic wants to give me options before starting to fix the car. if he can find a relatively good engine at a reasonable price which can fix current and potential future issues he probably thinks thats a better option. anyways, thanks again for your advice @Bowen

 

[Bowen]

Any progress?