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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 719 (ENGINE MECHANICAL - 3.8L (UNIT REPAIR))REPAIR INSTRUCTIONSVALVE GUIDE REAMING/VALVE AND SEAT GRINDING
1999 GMC Forward Control 5.7 R, Automatic
Valve Guide Reaming/Valve and Seat Grinding
1999 GMC Forward Control 5.7 R, AutomaticSECTION Valve Guide Reaming/Valve and Seat Grinding
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
Tools Required
J 8001 Dial Indicator Set
- Recondition the valve seats by grinding. Use an oscillating type valve seat grinder. Follow the grinder manufacturer's instructions. If the valve seat is too wide after grinding, use a 20 degree stone or a 70 degree stone in order to narrow the valve seat. The 20 degree stone will lower the seat. The 70 degree stone will raise the seat. Replace or recondition the valves if the seats are reconditioned.
- After grinding the valves, measure the valve margin. Replace the valve if less than the minimum recommended specification (0.79 mm (0.031 in).CAUTION: Bodily injury may occur if the cleaning solvent is inhaled or exposed to the skin.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.