Repairing the Taurus: Spark Plugs

Replac­ing the spark plugs used to be a chore that occurred every few oil changes at best.  It used to be one of the eas­i­est repairs for the do-it-your­self handy­man.  Spark plugs are, by nature, on the out­side of the engine.  In a stan­dard rear-wheel dri­ve car or truck, they face side­ways and up and are eas­i­ly iden­ti­fied by the wires lead­ing from their top back to the dis­trib­u­tor cap.  All you need­ed was a spark plug wrench, some new spark plugs and some qual­i­ty time to spend with your car.

Many mod­ern cars break all of these assump­tions.   It has become much hard­er to repair most spark plugs; espe­cial­ly in front wheel dri­ve cars but in return spark plugs have been made to last much longer — longer in many cas­es than peo­ple will own their cars.  Front wheel dri­ve cars turn their engines side­ways (which points some of the spark plugs to the rear).  New­er cars have far less space avail­able under the hood (which means every­thing hard­er to get at).

Tau­rus Engine In One Piece

Today’s dis­cus­sion is about the Ford Tau­rus.  Our par­tic­u­lar sam­ple is my 2002 SEL, but I’m led to believe that this engine is packed in sim­i­lar ways into a num­ber of front wheel dri­ve Ford and Mer­cury cars includ­ing the Sable.  My part­ner has a 2001 SE that has coil-on-plug.  In his case, there is a pro­ce­dure using uni­ver­sal joints and exten­sions that will allow you to remove the spark plugs with­out going though this rather lengthy pro­ce­dure.  You have coil-on-plugs if your spark plugs are topped by a round cylin­der that is screwed to the top of the engine.  My engine has the screw holes for COP, but it def­i­nite­ly has a coil-pack and that coil-pack is in the way of the uni­ver­sal joints and exten­sions plans (which my part­ner and I exe­cut­ed suc­cess­ful­ly on his car, BTW).  The pic­ture here shows the front three spark­plugs at the bot­tom — with no coil-on-plug.

Assum­ing you have the same Tau­rus or Sable, here’s how I got it done…

The first three plugs (num­bers 4, 5 and 6) are easy.  They’re right in front of you.  If you can’t find them in your engine, it’s a fore­gone con­clu­sion that the rest of this is too com­pli­cat­ed.  Change them.  I was cau­tioned that the engine should be cool or cold (to pre­vent strip­ping of the threads (real­ly bad)) and that I should replace with OEM parts.  The OEM spark plugs were only $8 at the deal­er, so it’s not too painful.

Remove the EGR Valve First

Now the back three will take us the rest of the time — a few hours for the first try.  We need to remove the plenum or upper intake man­i­fold to get at them.  There’s a few tricks to this.  One trick that I did­n’t learn until the sec­ond or third time that I removed this plenum was to remove the EGR (Exhaust Gas Recir­cu­la­tion) valve before doing any­thing else.  The exhaust gas is hot which requires that the hose is rigid.  This rigid hose and valve makes it extreme­ly hard to remove and replace the plenum.  You’ll note in the pic­ture here that it has two nuts and two bolts.  It also has two gas­kets and they were bad­ly worn in my case.  You should make sure you have new gas­kets on hand for this part at the very least.  If you’re hav­ing trou­ble locat­ing this pic­ture in your engine, the EGR is sit­u­at­ed between the throt­tle body (the thing that moves when you press the accel­er­a­tor) and the plenum.

Now, before remov­ing the plenum bolts, there are two con­nec­tors on the pas­sen­ger side (one wire and a dou­ble pipe hose) that you should remove.  On the dri­ver’s side, I remove the air fil­ter hous­ing because it’s easy and I dis­con­nect the for­ward fac­ing PCV hose (a rigid hose that con­nects to the for­ward valve cov­er).  There is also a large and a small hose that comes straight down from the throt­tle body.  The small hose is easy to remove (pull down, but you’ll be doing this by feel).  The large hose does a 90 degree turn and imme­di­ate­ly plugs into a rigid sec­tion that, in turn, plugs into anoth­er hose that sits in the val­ley of the engine.  It is mas­sive­ly eas­i­er to dis­con­nect the small rigid hose (as either end) than the large end that con­nects to the throt­tle body.  Dis­con­nect this.

Upper Intake Plenum Removed

One of the videos I found on the web went as far as dis­con­nect­ing the throt­tle cable and remov­ing the throt­tle body from the plenum (he removed the plenum to the bench).  This seemed like a lot of work to me.  I just removed the 8 bolts hold­ing the plenum down and raised it up — sup­port­ed by a handy bit of 2‑by‑4.  Note in this image the 4 (out of 6) orange gas­kets.  This is a bitch of a design.  They fall out eas­i­ly.  Keep care­ful track of them.  Do not let one fall in the engine.  I had also bought new gas­kets for this, but the first new set I got did­n’t fit well at all (which made them fall out more).  A sec­ond set fit bet­ter, but it may have been bet­ter to leave the orig­i­nals in there.  In my case, I was also fac­ing a vac­u­um leak, so they need­ed to be changed.

Once the plenum is up, you’ll be able to access the three rear spark plugs.  That part is fair­ly easy.  Remem­ber to be care­ful thread­ing your spark­plugs in (by hand at first) because a cross thread­ed spark plug means an expen­sive repair.  Again, my source mate­r­i­al said that a cool engine is less like­ly to cross thread.

Putting things back togeth­er is large­ly the reverse of what you just did.  I applied some light grease to the gas­kets to keep them in the upper plenum as I replaced it.  If you did­n’t remove the EGR, you’ll need to bring down the plenum for­ward of where it goes, get the EGR insert­ed and then shift it back.  This is when the gas­kets break loose and go down the low­er intake tubes.  Not fun.  If you did remove the EGR, it is eas­i­er, but not fool­proof.  I found this eas­i­est with a helper using a shop light to watch the gas­kets when I low­ered the plenum and then insert­ed the first few bolts while I held down the plenum.  Note that these bolts are spec’d to 10 ft-lbs — quite light.  I man­aged to break one at one point in my odyssey.  You might want to avoid that.

Put all the hoses back on where you found them.  Remem­ber the two on the pas­sen­ger side.  Replace the EGR and be care­ful with its gas­kets.  If you start the car and every­thing runs hor­ri­bly rough, chances are you for­got a hose or mis­placed a gasket.