How bad is it to change only some of your spark plugs?

[bowman316]

I have some pretty old and fowled spark plugs. and some are easy to get out, but some are really hidden behind pipes. So how bad would it be to leave some old ones in that i can't get to, and change others?

say change the right side, but not the left?

I have a 95 f-150 5.8.

I am waiting for the engine to cool down to try to pull the rest.

 

[rbh]

Re: How bad is it to change only some of your spark plugs?

You might as well bite the bullet on this one, for at least piece of mind as well you just never know how long they will last.

 

[642mx]

Re: How bad is it to change only some of your spark plugs?

You can do what you want, but I would replace them as a set. Its called, doing the job right.

 

[JRJ]

Re: How bad is it to change only some of your spark plugs?

As you change them all, remember, you probably won't have to change them ever again

 

[bowman316]

Re: How bad is it to change only some of your spark plugs?

here is the weird thing. of the 4 old plugs i have removed so far, they have all had the same, wrong, gap. the old ones had a gap of .077, while the right gap is supposed to be .044.
the whole right side of the engine had the same gap of .077.

now i am going to go work on getting the left side plugs changed.
i will post a pic of my old plug

 

[robert graham]

Re: How bad is it to change only some of your spark plugs?

Change them all at the same time, especially since it appears from your photo that the center electrode has burned down by a good .030"! I'm surprised your motor wasn't skipping or giving some indication, particularly under load. A spark plug is an item to remove, inspect and "read" for indications of the health of your motor, especially relating to hot/lean fuel conditions, carbon deposits, fuel mixtures, proper operating temperatures, etc. Good Luck!

 

[DJ]

Re: How bad is it to change only some of your spark plugs?

Do you put on half your underwear?

Replace them in sets. That way you have a claim for the aftermarket Spark plug maker to glom onto. Record the miles and date. trust me, you'll need it. Keep the receipts!

 

[Tim Frank]

Re: How bad is it to change only some of your spark plugs?

Do you put on half your underwear?

C'mon DJ...that's not really an option....at least with the underwear I buy...

Better question "do you only wear one sock?...."

 

[jlinder]

Re: How bad is it to change only some of your spark plugs?

All the plugs you removed have the wrong gap and are pretty bad, and it is a wonder that you engine is still running.

Wouldn't that be a good indication that the other 4 plugs plugs are probably the same? If so, doesn't that mean you are on borrowed time unless you replace them now?

 

[waterinthefuel]

Re: How bad is it to change only some of your spark plugs?

C'mon DJ...that's not really an option....at least with the underwear I buy...

Better question "do you only wear one sock?...."

Is that what is meant by running around half naked?

Just be glad your airplane mechanic doesn't only change the stuff that's easy to get to. I once had to grease a zert in a spot so difficult to access it took me an hour and 45 minutes to grease one zert. I could have easily skipped it as it's hard to see much less get to, but I didn't.

The problem lies, if your truck leaves you on the side of the road, the towing company won't charge you half price!

 

[bowman316]

Re: How bad is it to change only some of your spark plugs?

i finally got all 8 changed. it took me 4 hours (with a few breaks thrown in). those swivels you can put on the socket really help.

the hardest part was getting the wire off the plug.
2 of the wires left the tip on the plug. so i had to pull the tip off the plug, and put it back in the wire boot.


the truck runs a whole lot better now. more responsive to the gas petal now.
my buddy thinks i need to change the wires too. but f-that.

 

[JBow]

Re: How bad is it to change only some of your spark plugs?

my buddy thinks i need to change the wires too. but f-that


You really should listen to your buddy.

 

[Tim Frank]

Re: How bad is it to change only some of your spark plugs?

i finally got all 8 changed. it took me 4 hours (with a few breaks thrown in). those swivels you can put on the socket really help.

the hardest part was getting the wire off the plug.
2 of the wires left the tip on the plug. so i had to pull the tip off the plug, and put it back in the wire boot.


the truck runs a whole lot better now. more responsive to the gas petal now.
my buddy thinks i need to change the wires too. but f-that.

Automotive engineers should be forced to perform a few of the routine maintenance items on any engine/car they design.
maybe then we wouldn't have cars that need the engine moved to change an oil filter, 4 hour plug changes etc.....

 

[j_martin]

Re: How bad is it to change only some of your spark plugs?

my buddy thinks i need to change the wires too. but f-that.

Believe me, change them.

When you parted the electrode from the wire, and then stuffed it back in, you created a gap that will burn an arc path through the boot.

And the same deterioration that caused them to be sticky is making the insulation leaky.

they cost what? 6 gallons of gas.

 

[bowman316]

Re: How bad is it to change only some of your spark plugs?

wires are just wires, right. they prob don't go bad as quick at the plugs...

 

[j_martin]

Re: How bad is it to change only some of your spark plugs?

I had a shop change the plugs on my caravan. They itemized the bill for me.
5 bucks for the front 3
70 for the back 3.

 

[bowman316]

Re: How bad is it to change only some of your spark plugs?

yea tim frank,
my oil filter is in the most ridicolous spot.
on the back of the engine, half way up, right in front of part of the axle/suspension.
you have to reach down thru a ft of other parts from the top.
it is too hard to get from the bottom.

I wonder if other makes have a reputation for being easier to work on.

 

[642mx]

Re: How bad is it to change only some of your spark plugs?

I wonder if other makes have a reputation for being easier to work on.

Nope... they all suck, doesn't matter what brand.

And you can check your wires to see if they need replaced. Use a DVOM and check the resistance in them. They should be no more than 1K ohm per foot.

 

[mla2ofus]

Re: How bad is it to change only some of your spark plugs?

If a job's worth doing, it's worth doing right. If your rig's paid for just think of the repairs you do on it as still being less than a payment on a vehicle loan.
Mike

 

[bowman316]

Re: How bad is it to change only some of your spark plugs?

yea, that is a good way to think about it.
just wish i never bought such a rust bucket.