Oil on spark plugs

crc_73

Active Member
Mar 24, 2016
46
4
The car was in for the test about 10 days ago, failed on CO at low idle (0.38 when it should be less than 0.30).

I dropped the car into a mechanic last week as there were other issues with the ball joints and track rod ends, and asked him to change the spark plugs as well, and I'm to change the air filter and oil and oil filter this weekend, and give it a good drive to the test center on Tuesday.

Anyway, the mechanic left the old spark plugs in a box with the other pieces he changed, and 2 of them looked a bit oily, on both the threads and the tip end, and on the ceramic insulator, so not looking too good. But when I had a look at the area of the coil packs, there seems to have been oil leaking from the filler cap into two of the spark plug wells. Now, I don't know which wells the oily spark plugs came out of, but I'm wondering if oil is leaking down there, I can see it getting to the ceramic insulator, but will it leak through to the threads and tip of the spark plug from there?

I've driven the car for the past 45k miles, haven't changed the spark plugs, and don't know when they were last changed, but have changed the oil and filters 3 or 4 times. Would oil getting in there be a reason for the high emissions?

Also, that plastic thing that the coil packs are sitting in, is it easy to remove that after taking out the coil packs? I'm thinking I should give it a good clean, and try to get as much oil out of there if possible.

I don't know if the oil cap is faulty, does that happen? Or maybe I was a bit careless pouring oil in on some occasions.

Are there any other easy things I can do to help get it through the test? There are over 135k miles on the clock, so it may be getting to a point where engine wear might make it increasingly difficult to get through the emissions test, but the rest of the car is in such good condition, I'd like to give it every chance to last another year.
 

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mty12345

Active Member
Jun 17, 2011
3,768
475
bristol
I would say just give it a good drive to the test centre get it nice and hot, then hope that the new plugs and air filter make a difference. With a stronger spark and better air flow, you may squeak through. High CO could be burning oil, but more likely it was unburnt fuel. Good luck, ,let us know how you get on
 

300bhpdaily

Active Member
May 26, 2020
1,246
568
It’ll be the rocker cover gasket or someone spilt oil around the fill hole and didn’t clean it.
 

crc_73

Active Member
Mar 24, 2016
46
4
Had the car in this morning, and after changing spark plugs, oil, oil filter and air filter, the car passed ok, the CO at low idle dropped from 0.38 to 0.17. So that was ok.

However, I got stuck in crappy traffic on my way back to work (about 50 minutes for a less than 10 mile run), and I was sitting in traffic when the engine started making a very rough noise, almost like a rumbling, it did it for 5 or 10 seconds, then stopped, and a couple of minutes later it did it again for a few seconds. It was another 10 or 15 minutes before I got to work, but it only did the rumbling the 2 times.

I have a few things to organise here at work now for a few hours, but is there anything I should check when I get the chance? There were no warning lights on the dash either. I scanned the car last night for codes, but other than an open speaker and a couple of things with the locks (which will probably clear), there were no fault codes relating to the engine. I'll scan it again in the afternoon.

Car is a 1.4 petrol BTW.
 

crc_73

Active Member
Mar 24, 2016
46
4
Oil level is a little high, just a bit off the hatched area, but not up past the knuckle, if you know what I mean. I have a pump & tubing that I can suck a little out with.

If I was to say the rumble was coming from a particular area, when sitting in the driver seat, it felt like it was coming more from the left-hand side of the car.
 

crc_73

Active Member
Mar 24, 2016
46
4
Just wondering, if the radiator fan bearing acting up would give a noticeable dramatic effect in the car?

And other than allowing the engine to overheat, is there any way of making the fan turn on to see if it's working ok, like in vag-com or by shorting some connections?

Reason for asking is that when I turned the fan by hand, it seemed to be kinda ok in one direction, and not so great the other direction. Does it push or pull air through the radiator? I'd imagine it pulls cooler air from outside through the rad, rather than pushing potentially warmer air from inside the engine compartment out through the rad.
 
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