Spark Plugs: "Hot" vs "Cold"?

[Thuja Plicata]

Hello! I just bought a 1998 Ranger 4.0L V6 Manual 4x4 with roughly 148k miles. This is my first truck ever, and I could use some advice. Among other things, I need new spark plugs. My intention is for the truck to become my daily driver, which will entail occasional trips to the back country with wood, coolers and other typical camping gear. Do "performance" plugs make a difference? What about "hot" vs "cold" plugs? Also any thoughts on iridium vs platinum vs copper? Like I said, this is my first truck ever and I want to treat it right! Any suggestions welcome

 

[Dirtman]

You want double platinum or iridium plugs. Single platinum or copper will not last very long in that engine because it uses a waste spark system (without getting technical it means the plugs fire twice so more wear than a standard ignition system). Only use motorcraft or autolite brand, fords hate any other type of plugs. If the engine is stock do not screw around with any gimmicky performance plugs or try to fiddle with heat ranges, there is nothing to gain and plenty of potential for bad things to happen.

 

[SenorNoob]

Note that Ford specs 2 different platinum plugs for opposite sides of the engine. Get double platinum and you don't have to worry about which one goes where.

 

[gaz]

Hello Thuja:

Is your 4.0 an OHV or an OHC?

I do not agree with The Dirtman. My experience has taught me that the Ford 60°v6's like NGK V powers.

In regards to hotter and cooler, sometimes there is a reason for them. I run a 2.9L Ranger @ close 12.5 compression with 2 heat ranges cooler than stock plugs, to help the whole system function better overall.

With the same engine stock, I would use 2 heat ranges higher than stock to realize a better burn, for increased fuel economy. That is a 5 heat range spread, in purpose.

 

[Uncle Gump]

I'm Going to agree with dirtman... Put in it exactly what came out of it. Exception... if the original part number has been superseded by the auto manufacture. I personally have the best luck putting only Motorcraft or Autolite plugs in my Fords. Ford spends Millions of research dollars on spark plug development for each and every engine they build. Do you think NGK/Bosch/Champion/insert any other plug you want here does the same? Short answer is no... they don't. They take what Ford publishes and finds a spark plug that they determine is "close enough".

As for what @gaz states about changing to a plug 2 heat ranges hotter for a better burn... on a completely stock engine... I will caution you not to do this. He is probably lucky he hasn't preignited his engine and caused serious damage. DO NOT DO THIS! If he has done this and it worked... my guess is that his off brand plugs that are 2 heat ranges hotter are probably closer to what Ford determined the proper heat range plug is in the first place.

 

[Eddo Rogue]

My 4.0 ohv did not like the NGK's or Bosch, but loves the Autolite double platinum.

Waste spark system is why one side calls for double platinum. I run em all the way around.

Get Motorcraft or Autolite.

 

[Thuja Plicata]

Thanks for the input, I appreciate you taking the time to reply. I ended up going with Autolite double platinum. Attached is a quick pic of the engine. She's pretty clean but I am getting some thick, white exhaust..

 

[Dirtman]

White smoke has nothing to do with plugs. Generally means coolant is entering the cylinders. Bad head gasket, cracked head, really nothing good...

 

[cbxer55]

I've had so much trouble with plugs other than the factory ones. 3.0 that is. Still, I've tried iridium plugs, and the outer electrodes on the driver's side disappear in short order. Heck, even the factory plugs that were put in in January 2017, the outer electrodes were gone in three years, maybe 20,000 miles. Just changed them again here a few weeks ago.

I tried those funky E-3s in 2016, lasted all of 5000 miles and they were toast. I just put in double platinums once again.

 

[Thuja Plicata]

White smoke has nothing to do with plugs. Generally means coolant is entering the cylinders. Bad head gasket, cracked head, really nothing good...

Oh yeah, I know they aren't related. That's my next project though. A friend who is a professional mechanic is going to come over and help me determine exactly where the problem is. It is definitely thirsty for coolant but oil is not milky.