lexrex

I'm planning on replacing the spark plugs & wires on my '98 E320 sometime soon. It now has 108k miles. I don't know if the plugs have ever been changed. Is it worth it to replace the 6 coils at the same time? Or should I do plugs & wires only? Since the coils are over $100 each, I don't want to replace them unless I have to. The engine idles fine, no misfires, no codes, although there is occassionally a small vibration at idle.

E-Klasse

I wouldn't change the coils until you have a problem.

djantlive

Plug wires aren't cheap either especially you'll need 12 wires (2 plugs per cycl). If it's in good condition, I don't think you'll even need to change the wires. Save the money on coil also.

Gregs210

Hi, I'm just curious if you've decided which plugs you're going to use for the replacement.

I've heard some good stuff about the iridiums, but even the $13 (ea) discounted price is harsh. And even at that I can't believe I'd let them go for 100k anyway; I'm pushing 55K on my '01 and am thinking of changing them out around 60K.

I agree with the other posts on the wires and coils; no need to replace them unless you are aware of a problem with them. The rec seems to be to use a wire puller so you don't damage the wire or boot and then end up having to change them.

Enjoy the ride,
Greg

lexrex

Thanks everyone for the advice. I think I'll just do plugs only for now. My plan was to use the OEM plug, which I believe are Bosch Super Coppers??? I know to stay away from the Platinum +4s. What is the concensus on plugs?

Green E-300 DT

So why are you doing anything at all?
I gather that you didn't buy this car new, so you don't know the cars' history?

I have a motto. If it ain't broke, don't fix it!

As long as it starts right up, idles fine and most importantly does not 'miss'
under a heavy load or when straining up a hill, don't waste your money.

Let's see, 6 X $100 plus 12 X $13 plus the wires (?) plus labor. Sounds like $1500 to $2000 at the stealership.

Drive it until it starts acting up and then 'fix' it!

What was the mileage on the car when you got it?

Good luck.

E-Klasse

That is wht they call it Preventative Maintenance. Who knows where you will be when it acts up. It is like insurance.

Gregs210

Do the plugs, you won't regret it. Just like tires, brakes, oil, etc. they wear out over time and even if your car is running fine, you have no idea what they all look like unless you pull them for an inspection and know exactly what to look for. If they're worn, you may not notice an improvement in driveability -- the car is designed to compensate -- but you will notice an increase in mileage.

And if you have to pull them to inspect them anyway -- since you don't know the car's complete history -- for the relatively small cost of the replacements, why put the old ones back in unless they look perfect?

Keep enjoying the ride,
Greg

lexrex

Thanks everyone for the advice. I'm going to go ahead and do the plugs only, and if more needs to be done, I'll go from there. I'm planning to do the labor myself.

As a side note, I really love this car. I sold my 1980 450SL and bought the E320 in November. Driving the SL was like traveling back to the stone age compared to this, although nothing beats a sunny day with the top down. The E320 is in near perfect condition. This coming week I'm having my mechanic change the transmission fluid & filter, harmonic balancer, and fix a (hopefully) small problem with the A/C. (Passenger side blows cold air, but driver's side blows ambient.)

Fathead

Picked up my 98 w210 w/ 81,000 on Tuesday from my indie mechanic. $900 for belt, plugs, cables, coolant, oil, air & oil filter, front rotors & pads all around, tire rotation and balancing _ the works.

The plugs and wires made a big difference. Mucho more responsive and noticably better gas mileage.

Do it.

RhinoLT

Whats wrong with Platinum spark plugs?
I heard that Platinum sucks WHY???

E-Klasse

The only thing positive about a platinum plug is that they last longer than copper. In some engines they are ok or even put in by the manufacturer so they can claim that the car will go 100K miles before a plug change. But Platinum has a different resistance than copper because it conducts electricity different. The plug gap should be set differently for this reason. The gap settings will be called out in the manual for a copper plug and most people will just gap the platinums the same. Or in the case of the Bosch +4s, you cannot set the gap. I put a set in my 190E a long time ago and it ran like crap. I will not put them in my E320.

Gregs210

I've said it before and I'll say it again: nothing beats a good indie. If he's earned your trust you might consider posting a quick tale on the tech forum with your location and your mechanic's contact info for others to have.

By way of comparison, at my last service before the warranty expired, my dealer told me my rear rotors were warped, and since you don't replace rotors without pads, I should do the rear pads. Also, the front pads were worn and should be replaced. I don't doubt the veracity of their diagnosis; the fronts were worn and there was an occasional shudder in the brakes from higher speeds, but nothing pronounced. However, their estimate to do F&R pads and rear rotors: $975. OUCH! BAD DOG! You got the Front rotors -- which are more expensive -- plus all of the other work for $75 less than my brake quote. Excellent deal.

Enjoy the ride,
Greg

steve-p

My '97 E320 V6 has done 100,000 miles and according to the service records, has never had the plugs changed. The MB dealer says that the normal interval is about 50,000 miles, but since the cost is £300, the car starts immediately every time, it's smooth and powerful and it averages 27mpg (imperial - that would be 22.5mpg US approximately if my calculations are correct) why spend money when it's unlikely to make a great deal of difference in this case. It's refreshing for a dealer to advise against work, so I went along with their opinion. I'll probably change the plugs next year though along with the next minor service.

Green E-300 DT

If it ain't broke, don't 'fix' it!

Some people may have money to waste on needless 'preventive maintenance,' but I sure don't!

Where do you draw the line when performing that type of needless work?

Would you go ahead and rebuild or replace the motor before it showed signs of failure 'just in case?'

C280Sportster

I'm going with NGK Iridiums. They cost less than $7 a piece and from what I've read they work great.

Can't wait to get them in on Tuesday, I'll post the results.

Gregs210

Hey, C280. Mind sharing where you found the NGK Iridiums for that price?

Thanks,
Greg

lexrex

Rusty sells the NGK Iridiums (BKR5EIVX-11) for $7.56 ea.

lexrex

Replaced all 12 plugs on my E320 today. What a chore! It took me almost 30 minutes just to get the last boot off on the back driver's side cylinder. I'm sure more practice would have made the whole job go a lot faster. I used my fingers at the base and a 11/16" open-end wrench near the top to pop the wires off. The key to removing the boots isn't strength, but getting the proper angle & leverage with the wrench.

The original plugs had a little bit of carbon buildup, but overall looked pretty good for 110,000 miles.

I put in NGK BKR5EIVX-11 Iridium IX plugs. They all were pregapped at about 1.05 mm, so I didn't mess with the setting. The factory spec calls for 1.0 mm, but iridiums can run slightly larger gaps than copper or platinum plugs. Torqued them all to 28 Nm / 20 ft-lbs. Incidentally, the wires don't seem to snap on the NGKs as tightly, which may make life easier the next time they're changed.

With the new plugs installed, the engine idles more smoothly, feels smoother at higher RPMs, and seems to have better throttle response. I highly recommend the NGK Iridium IXs. They have a bigger electrode than the pricier Denso iridiums, so I expect that they'll last longer.

RobertG

Most maintenance is caused by poor maintenance or lack of good maintenance