I had my spark plugs changed today. The old ones were FILTHY, and one was even cracked, even though they only had 7500 miles on them (see photo)! Also, the gap in three of them were wider than in the other two (the mechanic who removed them couldn’t find the sixth one).
I’m curious what would have caused them to become like that. (The old ones were Champion Double Platinum.)
A couple of thoughts.
First, I had my catalytic converter replaced last year, as it was clogged. But I rode around with a P0420 code for a year or more before replacing it.
Also, valve cover gaskets were replaced at the same time, and they had been leaking for several years before that.
So I suppose one of those might have caused it? Just curious.
The plugs were replaced (by a mechanic who was working out of his home) when my car had 100,300 miles. Today, when the plugs were replaced, my car had 107,700 miles. So unless the guy didn’t replace the plugs but charged me for doing so (which I don’t believe happened), they have 7400 miles on them.
What I mean by that he couldn’t find the 6th one is that after he removed it he dropped it on the floor and it rolled somewhere in the shop and he couldn’t find it for the picture.
I’m willing to bet those spark plugs were never changed. 7500 miles? Hell no. I’m clueless to car stuff but even my Lexus IS and previous Camry at 60k miles never had the plugs looking so bad.
I’m going to assume the spark plugs were improperly torqued, or the octane fuel you use is low.
I just don’t think the guy ripped me off like that, though I suppose anything’s possible. Anyway, I asked ChatGPT “Can spark plugs with only 7500 miles become filthy and covered in carbon.” Here’s the response I got:
Yes, spark plugs with only 7500 miles can become filthy and covered with carbon for several reasons:
Rich Fuel Mixture: If the engine is running a fuel mixture that’s too rich (too much fuel compared to air), it can cause carbon deposits on the spark plugs. This can be due to a malfunctioning fuel injector, a faulty oxygen sensor, or a problem with the engine’s control unit.
Frequent Short Trips: Short trips don’t allow the engine to reach its optimal operating temperature, leading to incomplete combustion and carbon buildup on the spark plugs.
Poor Quality Fuel: Low-quality or contaminated fuel can cause carbon deposits.
Oil Leaks: If there’s an oil leak into the combustion chamber, it can cause carbon buildup on the spark plugs.
Cold Weather: Operating the engine in cold weather conditions frequently can lead to carbon buildup, as the engine runs richer when it’s cold.
Faulty Ignition System: If the ignition system (spark plugs, ignition coils, etc.) is not working properly, it can lead to incomplete combustion, causing carbon deposits.
Driving Habits: Aggressive driving with rapid acceleration and deceleration can also contribute to carbon buildup.
I’m guilty of 3 out of the 7!
#2 I work at home, and almost all my trips are short (less than 5 miles). Sometimes longer. But vast majority are nearby trips.
#3 I’ve been filling up with QuikTrip 87 octane fuel. I suppose that’s “poor quality fuel”?
#4 As noted, my valve cover gaskets were leaking for several years before they were replaced. I don’t know if that means there was “an oil leak into the combustion chamber.” But that seems pretty significant.
or the octane fuel you use is low.
I was always told there’s no reason to use higher-octane fuel unless your car requires it. Is that not the case?
Using 87 octane level is fine for cars that don’t require higher octane level. But there are some gas stations selling 85 octane and that would not work well with modern vehicles.
The pros seem to have taken a break from the site so far ( maybe due to the time ). They should be helping you eventually, so for now I’ll wish you the best in figuring out what could be the cause for the issue at hand.
The spark plug tips are normal for city driving and general abuse, they won’t remain clean for long.
The outside of the spark plugs are dirty from the oil leaks.
The second and third spark plugs were dropped on the floor causing the small gaps. It is OK to drop the old plugs, they go into the trash, don’t drop the new ones.
Why did you change the spark plugs after only 7500 miles?
I was in the car place getting my A/C recharged and I mentioned the vibrations I experience with my car, and the mechanic pulled one of the plugs and showed how the tips were covered in carbon. So it seemed the spark plugs needed to be replaced.
Well there is quick trip and kwik trip. Kt is pretty good gas, just confusing. Don’t know about qt. Maybe they were brothers or something like Erickson and holiday.
Over the past few years, the number of petroleum companies that have adopted the Top Tier standards has grown considerably. Of the “major” brands, I think that Gulf is one of the only NON Top Tier gasolines. Unless someone patronizes only the no-name stations, it’s pretty hard to not find Top Tier gas.
Years ago I was warned about using BP gas. Of course all here say but the mechanic had traced a lot of issues to people that had just filled up with their gas. On the road I will avoid them except I had to use them once on the tollway. Like China, once you get a bad reputation, earned or not, it will be with you for years.
I have a bp credit card that I got a notice to either use it or lose it. So I went down and charged $15 worth at the Mobil station. Then they wrote me with all the benefits of using their card. I only use credit cards for planes, hotels, and car rentals.
