How To: 3.0 Pulley(s) Install - Ranger-Forums - The Ultimate Ford Ranger Resource

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Old 03-26-2008
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How To: 3.0 Pulley(s) Install

Disconnect battery and remove intake tube as follows:

Remove tube

Loosen clamp at throttle body (5/16")

Remove MAF Sensor

Remove wiring connector

Remove assembly as one unit

Remove Serpentine Belt using wrench to relieve tension on tensioner pulley (15mm).
Belt must go behind fan blades for removal.


Loosen all 4 water pump pulley bolts. The bolts are 10mm. We are using a 7/8" socket
on the fan shaft to keep the pulley from spinning. Loosen all 4, then remove them.

Slide the pulley forward and install the 4 bolts back in place.

A fan removal tool is used to loosen the fan. This is a spanner type wrench.
It uses the 4 bolts to get its grip. The tool is available for sale or rent (sometimes free)
from a parts store. The fan removal is placed around the bolts. A 7/8" wrench is placed
on the fan wrench. Hit the wrench with a hammer and the shaft will come loose. In a
3.0 motor, it is righty loosey at the shaft. The shaft is moved clockwise to loosen it.

The fan cannot be removed with the fan shroud in place. Gently lay the fan into the opening.
Use a 10mm to remove the two fan shroud bolts.

Remove the fan and shroud together.

Install the new water pump pulley and install the ORIGINAL belt on the engine.
The belt tension will allow the Water pump pulley to be torqued and will aid in
the removal of the crank pulley.

Loosen, then remove 4 crank pulley bolts using a 13mm socket. Remove original
crank pulley and original belt.

Side by side of stock pulley vs pulley.

We used this technique to add extra tension during the removal.

Install the new crank pulley using the 4 original bolts. Don't worry about torquing it at this time.

Remove 3 Alternator bolts. (13mm)

Use air hammer to remove stock alternator pulley.

Use same air tool to install new pulley. If there is binding or scraping,
the alternator will need a little modification. The collar is too wide or too
deep for the pulley. File/grind as needed. Notice the shiny spot in the pic.

After alternator pulley is installed, reattach the alternator using the 3 bolts.

Remove idler pulley using a 15 mm.

Install Underdog idler pulley. Note that a spacer/washer must be used.
This keeps the bearing removal c-clip from making contact with the bolt/washer.
The space is gold in the pic to show the position of it.

Remove the tensioner pulley. Remove only the pulley using a 15mm ratchet/wrench.
The spring loaded portion can stay attached to engine.

Install Underdog tensioner pulley. Note that a spacer/washer must be used.
This keeps the bearing removal c-clip from making contact with the bolt/washer.
The space is gold in the pic to show the position of it.

Install new belt sized for the pulley combination.

Torque all pulleys to spec. Extra torque can be applied by grabbing the belt as shown.
Be carefull and go slow if using this method. Your hand can be pulled between the belt
and a pulley.

Reinstall fan clutch/shroud in reverse order of removal.

Reinstall intake air tube and related accessories in reverse order of removal.

Reconnect battery.

Start engine and check that no pulleys are wobbling.

Here is a before/after dyno run. The before (122.5 HP, 143.5 Torque) is an
all stock 2003 3.0 Automatic with full synthetic motor oil.
The after (130.9 HP, 154.6 Torque) is the same truck with the
addition of an Underdog crank Pulley with matching belt.

Last edited by graniteguy; 03-27-2008 at 09:42 PM.
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Old 05-12-2014
Join Date: Dec 2013
Location: Kalispell MT
Posts: 1
I can't seem to see any pics in this thread-am I missing something?
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Old 07-21-2017
MaDMaXX's Avatar
Join Date: Jul 2017
Location: Oregon
Posts: 744
Pics look to have long gone unfortunately :(
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