Hello all,

I wanted to ask some advice on my 1997 f150 4.6, with 195k on it. I bought the truck not too long ago, and having been doing maintenance on it. The truck didn't come with any maintenance records, and I have no idea if the plugs have ever been changed.

I don't have any misfire or engine problems, and get about 13 mpg combined which seems about right for a truck like this.

My question is, should I go ahead and try to replace them, or follow the
"if it aint broke don't fix it" approach? I have heard that changing the plugs on these older fords can be difficult, and the plugs sometimes snap. Any advice would be helpful.

Thanks,
Will

 

Just had mine changed at 125,000. Original plugs were extremely gapped at around .095, there supposed to be .055. Did notice about a 1 mpt differance and a touch more power, but that could be perceived as I just spent 500 dollars having a spark plug job done. I just did t have the nerve to do it myself.

 

You should replace them. You're leaving power and fuel economy on the table. You're also probably not burning completely, which is polluting the rest of the downstream components. Damage can occur well before a CEL is lit. Not to mention if a tip breaks you'll have alot more work on your hands .

 

That's assuming they are the OEM factory-installed plugs, but maybe, they were changed just prior to his buying the truck. Prolly not, but it's possible.

I'm with you, fresh plugs are important but unfortunately the hazards outweigh the benefits with regard to routine early or preventive replacement. I wouldn't touch a spark plug on a modern rig unless absolutely necessary. It sucks, but it's not worth the risk imo. Way too many horror stories out there where a routine plug change turns into some kind of 9 page saga.

 

I read the title and didn't really notice in his post that it was a lack of maintenance records. I took for granted he knew they were never changed because he owned it his whole life. I should read more closely.

 

Well they might be. I'm not sure I'd want to try and pull one to look, either. Maybe use an inspection mirror and determine if a different than OEM brand is installed or other clues. Is this one of the "three thread" POS heads trucks, or the POS "two piece" spark plugs, or some other flavor of spark plug related disaster? I thought the ole 97s were the ones that were launching plugs?

 

Yes this does have the thinner head. Torque the new spark plugs to 28ftlbs and you shouldn't have any issues. BUT....Probably should also recheck the torque after a few miles, just to be sure.

The 2 piece spark plugs, were not on this generation. They were on the next gen with the 3 valve engines. (this gen has 2 valve engine). Not completely sure but the 2 piece spark plugs may have been only in the 5.4?

 

Change them. These plugs have no issues coming apart when removing, the issue with these is them spitting the plugs out if not torqued correctly (original spec was 14 ft/lbs, new spec is 28 ft/lbs with no anti seize). Only use Motorcraft SP432 plugs (some have said Denso are good too, but no personal experience).

 

i had changed a set of 100k plugs and didnt have a busting issue at all, whenever you buy a car assume nothing has been done to it. swap out all the fluids, flush everything, wash it etc.

side note, i did have an issue where coolant had leaked into the plug hole because of a loose hose clamp and had to use the air compressor to blow out the gunk in it before i could break the plug loose, the back passenger side is a mother if you have a w code engine.

 

Alan did you use a breakfree or oil to help with the plugs? What a PITA, i'm looking at changing wires on the Ranger and it's like some kind of obstacle course to get in there.

 

Nope i knew there was already contaminates in the hole so i blew it out the best i could, jammed a rag down there with the plug still in and a very long(i think 24 inch flathead) and kept blowing the chunks out till i could get the socket on the plug. Also i had to put the socket on an extension then drop it in to fit and finagle the ratchet onto the extension. an angle or wabbler would have helped alot but i didnt see the need( i will eventually rebuild a 5.4 or bigger to drop in). looking back some pb blaster may have helped or some carb cleaner since it evaps fast. a word of advice, if its simple to take off and is in the way, take it off. i took off the entire intake when i did plugs and wires(also a good time to dishsoap them).