Join Date: Jul 2002
Location: Saturn (or SE Michigan)
4.6L Power Steering Fluid Flush
4.6L Power Steering (P/S) Fluid Flush
Supplies and tools:
3 quarts inexpensive P/S fluid (more, if needed)
1 quart premium P/S fluid (Service and Owner’s manuals state P/S fluid capacity is 1.6 pints)
Shop rags/paper towels and newspapers
Oil drain pan
1 gallon laundry soap or oil bottle
1 old banjo bolt from a Thunderbird brake caliper, or a drain plug, or something similar
Channel lock pliers, or spring clamp pliers
Small screwdriver or the appropriate ignition coil wire disconnect tool
4’ of hose, same I.D. size as P/S hose (or very close, anyway – clear hose is excellent for this)
1. Raise front of car. Support with jack stands. Disconnect coil wire connectors from coils.
2. Optional: cover floor of work area with newspapers (essentially, under P/S oil cooler and fluid reservoir return hose connection). The return hose is the hose connecting to the reservoir on the outer edge of the bottom of the reservoir. There’s another hose that connects at the bottom of the reservoir in the center. Do not disconnect this one.
3. Place oil drain pan under the P/S oil cooler at the return hose connection.
4. Using channel lock/spring clamp pliers, open and slide the return hose clamp off the connection and out of the way.
5. Disconnect return hose, and drain P/S fluid reservoir into oil drain pan.
6. Think to yourself: “THIS stuff is circulating through the power steering system?!?”
7. Use old banjo bolt/drain plug to plug return hose. Slide spare length of hose over connector on the P/S oil cooler, and place end into old gallon bottle.
8. Fill reservoir with the inexpensive P/S fluid. Have your assistant sit in the car, crank the starter motor, and turn wheels completely to the left and right while cranking the starter motor. Monitor the fluid level while this is in progress. Do not let the reservoir drain completely. Note: there’s no need to replace the cap each time, as the fluid will not spray out.
9. Say (or yell) “Stop” when fluid is almost gone from reservoir. Assistant must stop cranking starter at this time.
10. Observe color of fluid passing through spare hose into gallon bottle. If color is still dark, repeat steps 8, 9, and 10.
11. When color of fluid in spare hose is the same as the fluid poured into the P/S fluid reservoir, switch to the premium P/S fluid, and fill the reservoir. Repeat step 8 and 9 until 1.6 pints (.7 liters) of the premium P/S fluid has been poured into the system (make sure the reservoir is not overfilled).
12. Disconnect spare hose from P/S oil cooler (watch for dripping) and drain the hose into the gallon bottle.
13. Unplug the return hose, drain it into oil drain pan, and reconnect it to the oil cooler. Reposition hose clamp to secure return hose to the oil cooler connector.
14. Check level of P/S fluid. Reconnect ignition coil wires. Clear away oil drain pan, gallon bottle and hose, and newspapers. Lower the car.
15. Start engine, and slowly turn wheels lock-to-lock several times. Check fluid level again, and add fluid if needed.
This is the procedure my son and I followed on a 1994 Thunderbird, with the 4.6L engine, taking just about 30 minutes. Steering improvement is very noticeable, and there’s no discoloration in the steering fluid.