Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSBUICK1991CENTURY L4-151 2.5L VIN R TBIREPAIR AND DIAGNOSISSPECIFICATIONSMECHANICAL SPECIFICATIONSENGINECYLINDER HEAD ASSEMBLYSYSTEM SPECIFICATIONSTORQUE SPECIFICATIONS
1991 Buick Century L4-151 2.5L VIN R TBI
Torque Specifications
1991 Buick Century L4-151 2.5L VIN R TBISECTION Torque Specifications
Cylinder Head Bolts
In the sequence shown in figure 5:
1. Torque all bolts to 18 ft. lbs.
2. Torque all bolts (except No. 9) to 26 ft. lbs.
Torque No. 9 bolt to 18 ft. lbs.
3. Turn all bolts an additional 90° (1/4 turn)
Fig. 5 Cylinder Head Tightening Sequence:
In the sequence shown in figure 5:
1. Torque all bolts to 18 ft. lbs.
2. Torque all bolts (except No. 9) to 26 ft. lbs.
Torque No. 9 bolt to 18 ft. lbs.
3. Turn all bolts an additional 90° (1/4 turn)
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.