Benz-O-Rama

My E500 wasn't exhibiting any particular symptoms, but at 80K miles, I decided to change the plugs. All 16 of them.

After about 2.5 hours of intense labor, the car feels much, MUCH smoother. Power delivery is completely linear and it's hard to even tell the car is even running, at idle. It only took that long because every 15 minutes, I inevitably dropped a tool in the engine compartment. Not an easy task to fish those out.

As stated, my car didn't really feel like there was anything wrong with it, but after changing the plugs, you can feel the difference. It's like night and day.

I used the OEM Bosch 7422 and paid 4.37 per plug. Well below the $12.00 or so that the dealer charges. So, if you know how to use a ratchet, you can save yourself about $500.00.

Roehl

Wow that is good to know! Well I only have 43k on mine. How does your old plugs look like?

Benz-O-Rama

Well, none of them were fouled, but all of them showed signs of at least a little carbon buildup.

Roehl

OEM Bosch plugs are just regular plugs right? Can we use Iridium plugs on these cars?

Benz-O-Rama

Don't know. The Bosch 7422 are platinum tip and the OEM plugs. They're good enough for 100K miles, so that's good enough for me. Why change what works?

csumt76

you don't need iridium plugs... the regular joints are perfectly fine.

Air Marshall Eldritch

See my iridium plug conversion in the W210 forum.

tashakes

How many miles on your E? I am coming up to 70K, so I think I will change them this weekend.

Been spending some $$$ on maintenance lately, new radiator (preventive) with Blackstone Labs test (came out negative for glycol), 5-hour painstaking and finally perfect alignment done this Saturday (not for the faint of heart), so this is not bad at all, thanks for the heads up.

Benz-O-Rama

Just clicked over 80K. And as I stated, the car wasn't showing any signs of needing a tune up, but after I swapped plugs, you could really feel the difference. The biggest difference is when it's in gear, at idle. My car would always feel like it had a small misfire or vacuum leak at times. Dealer checked and checked and checked and could never find a problem. With the new plugs, you'd be hard pressed to even tell if my car is running at stoplights.

Very happy. My hands are all cut up because it's so tight in there, but very happy.

gnma

My '05 E500 maint. book states plugs to be changed every 91K or 5 yrs. The fact that there was little carbon buildup with yours @ 80K seems your car is running right on spec (even with your mods). Nice job, and thanks for the right-up!!

PS, I've got only 37K on mine, so I'm going to wait another say 2 yrs. or so before changing plugs, despite I will have passed the req. 5 yr point later this year...

vettdvr

Bosch 7422 are platinum tip and the OEM plugs and I got them from autohauasz. About $4.60 and change for each plug. About $68 or so for total set. My most difficult part was dropping the 27mm Torq to remove the coil pack into the engine compartment. I spent 2 hrs with the belly pan off looking for it. I allowed the car to cool over night for plug removal. However moving the car to put it on jacks I managed to burn my hand on the cat. Dang you would not think 15 seconds of running it would get so hot. The muff's were only warm.

The plugs came out pretty easy. Getting the cap off with 17mm wrench was difficult. I found twisting the cap made it easier to remove. I did use neversieze on the threads but only small amount. In removing the plugs I loosened the plug a small amount then tightened. Repeating this process and backing out a small amount each time. After about 2 full turns the plugs came out easily. They went in easier than removal with the neversieze. Caution,, this was a really small amount of never seize,, not gobs.

Pay attention to the coils. The wires are differnet lengths and you want the correct length in the correct place.

Total time.

2 hrs hunting for 27 mm torq and never found it
1 1/2 hrs changing plugs and test drive

total

3 1/2 hrs and extra bandages for the back of the hand.

would I do it again. Sure on 1 to 10 scale with 10 being hard, this was a 3.

But please don't start the engine even for a few seconds. It does get a bit warm to the touch.


Small point. The plugs removed looked NEW with a small brownish tint. The new plugs ran just like the old ones. But it is good to change the plugs before you have problems and trash the cats'.

M-bENZ

is that part number will be same as my CLK ??

Andy

Roehl

Wait a minute, 16 plugs??? I didn't see that comin'. LOL!!! Why is it 2 plugs per cylinder? Daaaamn, this thing eats alot of plugs. LOL!

No wonder why it drains so much amps during start-up.

vettdvr

Check your owners manual. If it calls for the Bosch F 8 DPP332U then the 7422 will be the same. If you have a different # in the manual you will have to cross reference.

mcleantmw

I might try doing my plugs..........I have 65500 miles on my 03 E500 so will wait another year. What torque pressure did you use on the plug installs?

Benz-O-Rama

Manual calls for 18.5-22 ft-lbs. The one's that I couldn't get a torque wrench on, I winged it and put them, how do the German's say......Gutentight.

gnma

I've often wondered the same. Why 16 plugs? Is this common for V8 motors?

SouthDakota

Not common at all, but has its merits. Dual flame front potentially can create more power due to faster burn, and double spark means half the chance for a misfire. Pretty sure that if there were four valves it would eliminate the additional plug though.

dvmak

The use of dual plugs is not a new concept, implemented for various reasons but not common ...

Generally it's for some small HP gain and mostly to reduce emissions ..

E55AMGGG04

Can you change the spark plugs using my full coverage warranty or is that considered wear and tear?

ap10046

Does Splitfire make plugs that would fit our cars? Had a 1972 Trans-am 455SD that literally changed persona after chucking on some Splitfires!!

D099y

my problem is that when i'm at a red light or stop sign. my car kinda vibrate, but it will stop when i put into netural. will changing the plugs help ??

vettdvr

Plugs are wear/tear items you pay for.

Rough idle "might" be plugs. I changed ours at 80,000+ miles. It does appear smoother. However the wife didn't notice any change. (but if it was hitting on 7 she might not notice.)

vettdvr

You might find "other" plugs that fit. But why try it. The factory Bosch work well, cheap enough and relatively easy to install. Why switch for some snake oil plugs.?

takitoz71

hey vett bout to change my spark plus this friday since my car broke down on me this past weekend and it towed to the dealer to see what was wrong with it. turns out to be the crank shaft sensor which had to be replaced and came out to close to $385 but only paid $100 since my extended warranty requires a deductible. dealer recommended to change out spark plugs soon. bought the spark plugs from autohaus since i saw you bought them from there too. is there anythin specific i need to for job? let me know thx.