ravi kandanat

Hey,
I am thinking to change my set if spark plugs on my 48000kms run w204 facelift 2012 c200 cgi 1.8 turbo petrol as it's about 8 years
cud u suggest the part number in my car ?is it better to use ngk iridium or go for bosch or oem stock??
my vin number Is as follows : WDD2040486L051133
thank you

190Efan

Is your car having any symptoms that leads you to think you need to change the spark plugs? Typically, most spark plugs these days are good for 100,000 miles. Since your car only has 48,000KMS, you're still a good ways from needing to replace the spark plugs.

ravi kandanat

thank you or your reply
I was jus thinking to get it changed since car is a 2012 model so 8 years and we have ****ty fuel here in india so thought I could get an even better throttle response with iridium plugs . Could you tell me what exact issues I shall be looking at if I have bad plugs

190Efan

That's not the case with spark plugs. You replace them if they're at the mileage they should be replaced at or if your car is exhibiting symptoms that are causing drivability issues for which there can be many. Throwing parts at a car for the sake of throwing parts at it is unnecessary and can get expensive. If you're worried about poor quality fuel, you need to be checking your fuel filter and your fuel lines. If they having any clogging, that will also cause problems.

ezshift5

IMHO Efan makes a cogent point here. Our C250 1.8 has circa 38k - same plugs since 2014 purchase. MPG is a good yardstick to measure plug health (MHO again). I have not been able to take any long highway trips this year........(previous years have calc'd out to 34-35 MPG)

Around town fuel numbers have not changed (so no new plugs for this sailor).


best to all,


ez

karlt10

Copper vs Platinum vs Iridium is largely about plug life. While there is an issue of less resistance requiring less voltage, hey are not an assurance of more power, better idling, etc. A few years ago there was a dyno shop site that had a full comparison of the various plug types and subsequent HP figures. The numbers were a wash.

My other car is a 2005 Mazda 6 wagon. After adding headers, high flow cats, cold air intake, effectively removing the EGR valve, and adding performance coils, I began messing around with various plugs. Not just electrode material, but even heat range. The first change was to a one-step colder plug. Although there hadn't been problems, there was still an improvement from this change. After that, changing to Bosch Platinum, Platinum +4, and NGK Iridium, made no difference. In fact, I had a random misfire with the +4. For the hell of it I went back to the OEM NGK, just one step colder. It runs perfect on those plugs.

https://www.enginelabs.com/engine-te...-from-opinion/

ravi kandanat

does the w204 facelift c200 cgi have a removable fuel filter external ? .I thought it jus had the one inside the fuel pump under seat

190Efan

My engineer father taught me that changing spark plugs is about the mileage on the spark plugs and whether or not the car is having any symptoms that bad spark plugs may be the cause of. It's not about how many years the spark plugs have been in the car. Changing out perfectly good spark plugs just because they've been in the car for a number of years and without any other symptoms is a waste of time and money. In addition, with all of the electronics on the newer cars not using an OEM spark plug may cause a whole new set of issues.

karlt10

If you search OBD-II codes, you won't find one that says 'Cylinder X Spark Plug Bad'...

There is no way to know if a spark plug is 'perfectly good' without swapping it out with a known/suspected good one, such as a new one. Even then, the new one could have an issue. A spark plug is a secondary item. It has no sensor or means of reporting it has an issue. You would only find out if the insulator leads to an event such as a knock or misfire that is picked-up by a sensor.

Examining the plugs, or even swapping them out for new ones is always a good idea, provided they are easily accessible. While not likely if installed for some time, you may find the aforementioned cracked insulator. You may find a worn electrode. You may find a plug soaked in oil.

As for non-OEM plugs causing a 'whole new set of issues'- not likely. In part because the only issue that could be created would be a misfire. Even that is highly unlikely when using a name brand plug and the model which the manufacturer suggests. Which, yes, is possible. GM's Quad-4 was notorious for experiencing hot temp misfires when using Bosch Platinum. But

190Efan

Sorry but you're not entirely correct. You can tell alot by visually inspecting spark plugs. Depending on what they look like they can help with diagnosing all sorts of problems. Given the complex electronics on the newer cars, it's possible for there to be problems when using non OEM parts. Most spark plugs on the newer cars now are good for 100,000 miles. The OP's car is currently well below that mileage. I will always take my engineer father's advise given that he had 2 engineering degrees, was a member of the Society of Automotive Engineers and had more than 40 years of engineering work experience.