chenripp

I recently want to replace the old spark plugs on my 04 sable 12V,
which has 90,000 miles. However the rear three are really hard to
reach.

1. Do I have to diassemble the upper intake manifold to get access
to the rear 3 ones?

2. If the upper intake manifold has to be blown off, do I have to
replace the upper intake manifold seal (6 rubber O-rings) as well?
It's $20, sucks. If I still use the old O-rings, would it be OK
to keep a good seal?

3. The upper intake manifold is mounted by 4 bolts. (really stupid,
3 bolts have long stem on top so I have to find deep sockets
from autozone). Are the bolts in metric or English units? Seems
neither 8mm or 5/16" sockets are a little loose for that bolt.

4. The new spark plugs are Bosch Platinum +4. I hope they will
last to the lifetime of the engine without need to replace them again.
I bought anti-seeze grease from autozone and want to use
during plugs installation. The instruction of Bosch Plt+4 says
that the thread of the plug is nickel plated and doesn't need
anti-seeze greese. Should I follow it?

Thanks,

SHOZ123

You should take the upper intake off to clean it anyway. It will be full of oil and carbon. You probably can reuse the gaskets. I reuse the thin steel type by painting them immediately before reassembling.

Don't put the Bosch +4s in. You will have problems with misfires probably.


Bolts are all metric, get a set.

chenripp

Thank you for the advice.
Why cann't I use the Bosch Platinum +4? Did you ever try them before?
I checked several online store, P+4 is always an option for my car.
I also ordered a Bosch spark plug wireset, which is goint to be compatible
with the plugs. I hope this work will improve the current poor mileage of
16.3/19.3 to a significant one.

SHOZ123

Many people have issues with the Bosch +4s and the Taurus. It's the multiple electrode thing.

Can't go wrong with Motorcraft or Autolite.

jwko

Thats exactly what I was told at the parts store about the +4's. I installed the Bosch + 2's in my 01 at 75k and they made one heck of a difference and have had no problems at all and im now at 90k. Other than that I recommend the Autolite Platinums.

tbird100636

I work at a Dodge Dealer. Every car that I've seen with the wacky multiple electrode spark plugs like the Bosch +4's have had problems with misfiring. After installing the stock plugs the misfires went away on every vehicle. As for which plugs to use, just get the original Motorcraft plugs. They do sell them at Autozone if you don't want to go to the Dealer.

00gtr1

You can get to the back 3 plugs with the intake on it is very easy just remove your air intake from your throttle body then you can reach behind the intake and work. As a Ford tech I advise not to use the bosch because of the probllems everyone mentioned. you will not see any performance or fuel mileage gains, use only motorcraft plugs and wires. If you do remove the upper intake you should replace the O rings cuz with that many miles if you reuse them you could can lean codes afterwards. Anti-sieze would't be a bad idea on the plugs and be sure to put dieletric grease in plugs wires for easy removal in the future

chenripp

Today I pulled out one spark plug to check how bad it may be
after 90,000. Surprisingly it looks in pretty condition, no heavy
carbon deposit nor other abnormalities. Yet it did look as if the
gap between the tip and ground is a little bigger. I use the gap scaler
to measure the gap, and it is 0.061", larger than 0.044", as indicated
by the manual.

Can this explain why my 04 sable vulcan gives a poor MPG (16/19)?

The spark plug is Motorcraft Platinum AGSF 32PM. I guess they are the
original ones from the manufacturer. Since this car was previously owned
by lease, I assume that these plugs have never been replaced . No idea
if the rental company would replace spark plugs as a normal maintenance.

Is 0.061" or 0.044" the correct gap for this spark plug? I'm confused.
If 0.044" is the right gap, I think probably the worker just installed them
as they were and omitted to readjust the gap.

jwko

As the tip of the spark plug wears, the gap will become wider. Its time for new plugs. 044" should be correct.