best spark plugs
 

I would like to replace the plugs and the cold start valve on my 1988 190e 4 cyl

I went to fast lane and found the cold start valve right away not problem but it is giving me several choices for the spark plugs. I dont want to get the wrong plugs, but I do want to get the best plugs.

Could somebody tell me which to get or send a link, should these plugs be gapped after I get them or are they already gapped? thanks for any help.

Look in your owner's manual to see which plug to use. Generally you should use a Bosch copper plug (not a platinum!).

I've never had to gap any Bosch plug recommended for my 300E, because they already had the correct gap. However, it wouldn't hurt to verify they were correctly gapped.

Your engine should take a tapered seal spark plug torqued to 10 to 20 NM.

Get yourself a can of HD silicon spray and spray the inside of the spark plug wire boot before putting the wire on the plug. It will make it easier to get the wire off next time w/o damage.

I may get get some flack from other professionals,but I never use anything but NGK.

Peter

Never use Platinum spark plugs. They are not fitted for high heat. It will stall your car and gives off rough idle after awhile.

Actually, new Mercedes engines all have platinum plugs and these engines run hotter than previous engines. However, it IS true that platinum plugs should not be used in engines prior to the current 3-valve engines. The older engines were designed to operate best with Bosch copper plugs.

Platinum plugs are designed to last longer not because of the use of platinum but because the tip is protected. The result is that they are not as effecient (at least in older engines) as a normal copper plug.

The recommendation is correct, no platinum plugs prior to the current engine line.

Replaced the stock platinum plugs in my 97 C280 at 60K miles with Champion Platinum plugs and after another 55K miles the car runs flawlessly. What doom awaits?

If it runs well, who can argue with success?
The original plugs were Bosch F8DC4, actually the were probably F9DCO, but that number was changed to F8DC4.
On Machnumber's car the 4 cyl gas motor, the torque spec IS 20nm, not 10 to 20nm.

+4 worked ok for me
 

FWIW I have had good results with the Platinum +4s in my 300E.
No hot weather problems during this very hot summer.
This is not to dispute any recommendations, just a data point...

Gaps on new plugs (that require gapping) can vary significantly, and really should be checked.