How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Robert Your Own Question
Robert, UK Qualified Car Technician
Category: Car
Satisfied Customers: 4716
Experience:  Fully qualified / self employed garage technician in the UK
Type Your Car Question Here...
Robert is online now

Hi,In June this year my partner had her Skoda Fabia VRS

This answer was rated:

Hi, In June this year my partner had her Skoda Fabia VRS S-A, registation FV11VUC serviced at a local independent garage. As part of the service the spark plugs were replaced using NGK5960 plugs. Last week the car started misfiring and an engine warning light came on. As she had to take the car to the Skoda dealer she had bought it from for an unrelated matter, she asked them to investigate. The initial response was: “As discussed re. Skoda Fabia FV11VUC with the engine warning light coming on.  Upon initial inspection with our diagnostic equipment following a road test we found multiple codes relating to misfires on all 4 cylinders and various other trouble codes which could all be related to an engine misfire. We have removed the spark plugs as part of our initial investigation and found all spark plugs are white at the tips which would indicate they are burning too hot/cold. Based on a quick search of NGK’s website the part number for the spark plugs fitted to your vehicle indicate they are suitable for an engine code of CHFA and your engine code is CAVE. We will remove the cylinder head as requested and report on the extent of any further damage as required.” Yesterday she received a further reply: “On receiving your vehicle we have checked and confirmed the engine warning light to be on, also confirmed that the vehicle has a misfire evident – carried out guided fault find and removed spark plugs for inspection – found to be non genuine spark plugs fitted, checked compressions and confirmed to be low on cylinder 1 – removed cylinder head and found carbon type build up on cylinder head/valves/pistons – wear also found to cylinder bores – carried out wet cylinder test, cylinder number 2 leaking to excess – vehicle requires engine to be replaced – please see prices as follows; Labour £1680.00  (including 8.0hours already authorized) Parts £3580.98 Total including parts, labour and Vat £5261.16”. Today I went to the garage which carried out the service who expressed surprise both at the engine damage and the supposed cause. They confirmed that the plugs which had been removed were the model number that they had fitted. They said that they had sourced the spark plugs from Allwoods Automotive and that, as is their practice, had quoted the car registration number to be sure of receiving the correct parts. Subsequently they said they had contacted Allwoods who confirmed to them that the correct plugs had been supplied. I am at a loss to understand what is going on – can you help? Tom

Hi..Apologies for the delay..

Hopefully I can help..

So those plugs you pictured - these are the ones fitted by the service garage/removed by the dealer?

I note you say the service garage "confirmed" that the old plugs are the same as the new ones by numbers.How did they go about that? they still have the old plugs to confirm?

Is this the first time the cars had replacement sparkplugs from new?

What about Oil level,did they double check that?

Customer: replied 3 years ago.
Hi Robert,
Yes those plugs pictured were fitted by the service garage and removed by the Skoda dealer which still has them. I meant that the service garage confirmed that the the plugs they fitted were the same as the ones pictured, not that they were the same as the ones they had removed. I've checked the previous service invoices and none of them mention replacing plugs. My partner's not here at the moment to ask, however, and the service record is in the car so I can't check that.
The Skoda dealer hasn't mentioned the oil level. This model is notorious for using a lot of oil and we've had that investigated by Skoda who have said its usage is within the tolerance level. We know, therefore, to check and top up regularly.
Best wishes,

Hi.there thanks for your reply

Ok..Ive actually got NGK's 2014 List for all sparkplugs and lists all the Fabia 2 models - Its a pity you couldnt actually see the old plugs as this would of confirmed wether it was the wrong plugs or not,and whos in the wrong here..What i can say is though that the plugs you have there pictured and the code i see there ( ZFR6T-11G ) "are not listed" for that engine you have -

If the Dealer has confirmed your engine is a "Engine code CAVE" which is the 1.4, 4 cylinder, 132kw...... Then that uses a very different plug - The Plug that should of been in there and listed as such is ( PZFR6R8EG )

Skoda,VAG Part numbers spark plug 'longlife' = 03C905601A / 03C905601B (NGK - PZFR6R8EG)

The CHFA the dealer mentions is the 1.2, 3cylinder 44kw engine.......

The differance between those plugs is the heat rating and the Gap..the ones you have there in your picture has a plug gap of about 1,1 where as the plugs that should of been in the engine have plug gap of 0,8 - so the differance is plain to see - too wider gap! on the plugs you have there in the picture / wrong plug and would likely of been contributery factor in the excess carbon fouling within the engine - the white deposits

I can give you a copy of the sparkplug list i have to see for yourself if required..but clearly as far as i can see i would be inclined to agree with the Dealer here that the plugs are indeed the wrong type for that engine you have in your car..and they may have gone by the standard 1.4 63Kw engine that uses these ZFR6T-11G plugs....I do hope this helps..If you require to ask anything further then just continue before you rate

Hi..there..Just wondered if required any further help..? If not and nothing further is required - then please dont forget to rate..very much appreciated..Regards Rob
Customer: replied 3 years ago.

Hi Robert,

I don't know why you didn't get my last message, but I asked for a copy of the spark plug list.

Can you send it through a message here or do you need my email?




It didnt appear to come through? But i can supply the list below here..Just ignore the TDI's as that diesels for glowplugs...Hope this is of help to you..

Customer: replied 3 years ago.

Hi Robert,

Can you give me the source of your list please? When I look at the NGK catalogue it doesn't give this level of detail.




The lists actually from the Book that we/my garage have - NGK 2013-2014 Sparkplug and Glowplug catalogue..I can only really copy upload sections from it im afraid..hence as above..Have you tried NGK own imagine they will have download able lists on that somwhere..failing you could actually confirm via NGK itself to maybe if sure they will confirm exactly whats highlighted above..... Added to the list of numbers..ive got a friend who works in the trade too,VW Specialist..basically VW/SKODA/AUDI/SEAT all VAG and share alot of parts,engines and he sent me another NGK number SIZFR6B8EG?... But however still incorrect plugs for that engine...

Robert and other Car Specialists are ready to help you
Customer: replied 3 years ago.

Hi Robert,

Following up on my previous question:

Everyone now accepts that the wrong plugs were used, but the garage that fitted them, the company that supplied them are all questioning whether fitting the qwrong plugs could cause the amount of damage that Skoda say has been caused. I'm going round in circles trying to get some kind of definitive answer but am getting nowhere. Can you help?


Yes..well there have been alot revisions on these plugs as i highlighted above..added to that these engine arent particular unknown for carbon problems..hence why no doubt the plug revising/ecu update i recall for these engines...never the less..its a pitty really that the fitting garage didnt still have these old plugs to confirm wether it was the same plugs they installed or not..but the main problem here is due to the wrong gap/heat range of the plugs you had installed,whether this was actually on the car from the beginning or fitted by the service garage.i cant say.only those working on that car will know...........Normally black, sooty, dry-looking deposits indicate a rich air fuel mixture usually, weak ignition or wrong heat range spark plug (too cold). The carbon-based deposits are conductive, bit like oil fouling,which these engine are renowned for as you'll already know, and will allow the voltage coming out of the center electrode of the spark plug to track down the core nose rather than jumping the gap. This will result in an engine misfire and further aggravate the carbon fouled condition.
On all engines, severe vacuum leaks can decrease manifold vacuum, resulting in a rich condition. Weak and/or damaged secondary ignition systems will fail to spark across the gap lowering combustion chamber temperatures and promoting carbon deposits. This condition could also result from continuous low speed driving or poor cylinder compression - in some case carbon can build up so much so around the valves that during ignition the valves may not be fully closed properly due to the carbon fouling thus causing a weak compression/incomplete combustion/increased carbon fouling..manufacturers where applied select a heat range plug that keeps the insulator tip hot enough to keep it clean of conductive deposits (carbon), but not so hot that the spark plug causes pre-ignition..............