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.
Engine Compression
Check engine compression with engine at cranking speed with battery fully charged, engine at normal operating temperature, all spark plugs removed and throttle wide open.
| Application | Specification | |
|---|---|---|
| Normal Compression Pressure | ||
| ES300 | 218 psi (15.3 kg/cm2 ) | |
| GS300, IS300 & LX470 | 192 psi (13.5 kg/cm2 ) | |
| GS430, GX470, LS430 & SC430 | 178 psi (12.5 kg/cm2 ) | |
| RX300 | 213 psi (15.0 kg/cm2 ) | |
| Minimum Compression Pressure | ||
| ES300 | 145 psi (10.2 kg/cm2 ) | |
| GS300 & IS300 | 156 psi (11.0 kg/cm2 ) | |
| GS430, GX470, LS430, LX470, RX300 & SC430 | 142 psi (10.0 kg/cm2 ) | |
| Maximum Variation Between Cylinders | ||
| Except ES300 | 14 psi (1.0 kg/cm2 ) | |
| ES300 | 15 psi (1.1 kg/cm2 ) | |
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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