P0128 code fixed with new thermostat
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Joined: Sep 2012
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From: LI, NY
P0128 code fixed with new thermostat
My 2004 F150 4.6L had been a bit shy on cabin heat last winter, but the Temp gage showed steady 3/8 reading and she was running fine, so I ignored it. 
Last week, as the morning temps hint at coming Fall, the Check Engine lamp reveals a P0128 code (Coolant Temp Low). My ODB-II reader shows hot engine running temps between 170-174 degF. Catalog (Rock'in Auto) shows Ford OEM t-stat is 192 degF, so off to Advance I go:
1 Stant Premium Superstat (195 degF), and
1 Rubber o-ring for Water Outlet Neck, and
1 One gallon of Zerex G-05 (50/50),
1 Tube of Never Seize grease (for all bolts & screws)
Tools:
3/8 ratchet set (10mm for Outlet Neck bolts)
1/4 ratchet set (for everything else)
slip joint pliers for radiator hose clamp (reused)
The job could not be easier (make sure engine is cool):
1. Loosen pressure cap on coolant reservoir.
2. Loosen petcock & drain about 1 gallon of coolant.
3. Loosen clamps & remove air intake resonator (between throttle body & air filter).
4. Remove 3 bolts holding Pwr Steering reservoir bracket.
5. Remove upper radiator hose from Outlet Neck.
6. Remove both 10mm bolts for the Outlet Neck.
7. Tap the Neck with you palm to break free & pull straight up.
8. Clean bottom of Outlet Neck, especially where it hits o-ring.
9. Pry old O-ring out and discard.
10. Lift out old T-stat with fingers.
11. Drop in new T-stat (54MM) with spring side toward engine.
12. Press in new O-ring (54mm) with fingers (snug fit).
13. Do not use any RTV or gasket material (none required).
14. Drop in the Outlet Neck (the 45 bevel & O-ring make it water tight).
15. Apply Never Seize to the lower 1 inch of bolt threads.
16. Insert & tighten the two 10mm bolts (4 inch long) using your 1/4 ratchet (so you don't over torque em).
17. Reinstall upper radiator hose & clamp (i reused mine).
18. Apply Never seize grease to 3 bolts for Pwr Steering Reservoir bracket.
19. Reinstall bracket.
20. Reinstall air intake resonator box.
21. Add a gallon of new Zerex G-05 coolant to pressure reservoir.
22. Check for no leaks from hose, neck or petcock.
23. Drive around and add to fill line as air self purges from system.
24. Remember, Never open coolant pressure reservoir with hot engine.
Drove around the neighborhood with ODB-II connected and Coolant Temp showed 190-194 degF. NICE. I'll be toasty this winter. The temp gage now shows 1/2 scale (or needle straight up).
Hope this helps you one day. Sorry there are no pictures.
My only issue is: Why is it so hard to find Zerex G-05. It is the base formula for all FORD vehicles and should be in every store. Here's a link on coolant I found useful:
http://www.motor.com/article.asp?article_ID=816
Last week, as the morning temps hint at coming Fall, the Check Engine lamp reveals a P0128 code (Coolant Temp Low). My ODB-II reader shows hot engine running temps between 170-174 degF. Catalog (Rock'in Auto) shows Ford OEM t-stat is 192 degF, so off to Advance I go:
1 Stant Premium Superstat (195 degF), and
1 Rubber o-ring for Water Outlet Neck, and
1 One gallon of Zerex G-05 (50/50),
1 Tube of Never Seize grease (for all bolts & screws)
Tools:
3/8 ratchet set (10mm for Outlet Neck bolts)
1/4 ratchet set (for everything else)
slip joint pliers for radiator hose clamp (reused)
The job could not be easier (make sure engine is cool):
1. Loosen pressure cap on coolant reservoir.
2. Loosen petcock & drain about 1 gallon of coolant.
3. Loosen clamps & remove air intake resonator (between throttle body & air filter).
4. Remove 3 bolts holding Pwr Steering reservoir bracket.
5. Remove upper radiator hose from Outlet Neck.
6. Remove both 10mm bolts for the Outlet Neck.
7. Tap the Neck with you palm to break free & pull straight up.
8. Clean bottom of Outlet Neck, especially where it hits o-ring.
9. Pry old O-ring out and discard.
10. Lift out old T-stat with fingers.
11. Drop in new T-stat (54MM) with spring side toward engine.
12. Press in new O-ring (54mm) with fingers (snug fit).
13. Do not use any RTV or gasket material (none required).
14. Drop in the Outlet Neck (the 45 bevel & O-ring make it water tight).
15. Apply Never Seize to the lower 1 inch of bolt threads.
16. Insert & tighten the two 10mm bolts (4 inch long) using your 1/4 ratchet (so you don't over torque em).
17. Reinstall upper radiator hose & clamp (i reused mine).
18. Apply Never seize grease to 3 bolts for Pwr Steering Reservoir bracket.
19. Reinstall bracket.
20. Reinstall air intake resonator box.
21. Add a gallon of new Zerex G-05 coolant to pressure reservoir.
22. Check for no leaks from hose, neck or petcock.
23. Drive around and add to fill line as air self purges from system.
24. Remember, Never open coolant pressure reservoir with hot engine.
Drove around the neighborhood with ODB-II connected and Coolant Temp showed 190-194 degF. NICE. I'll be toasty this winter. The temp gage now shows 1/2 scale (or needle straight up).
Hope this helps you one day. Sorry there are no pictures.
My only issue is: Why is it so hard to find Zerex G-05. It is the base formula for all FORD vehicles and should be in every store. Here's a link on coolant I found useful:
http://www.motor.com/article.asp?article_ID=816
