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 MANUALSSUBARU1990XT-6 4WD L6-2.7L SOHCREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMSPARK PLUGDESCRIPTION AND OPERATION
1990 Subaru XT-6 4WD L6-2.7L SOHC
Spark Plug: Description and Operation
1990 Subaru XT-6 4WD L6-2.7L SOHCSECTION Description and Operation
Spark Plug Cutaway View:
PURPOSE
Spark plugs allow high-voltage secondary current to arc across a small air gap to ignite the air/fuel mixture in the combustion chamber.
Spark Plug Temperature:
HEAT RANGE
The temperature of the spark plug is determined by the length of the insulator and the size of the heatsink area. The longer the insulator, the smaller the heatsink area will be. This causes the spark plug to be hotter.
The heat range of the plug is determined by its ability to dissipate heat created during combustion. If too cold a plug is used, the possibility of fouling is increased. A plug that is too hot can cause preignition. Hotter plugs tend to burn cleaner with less deposit build-up. They can be used for stop-start city driving, but not for extended high speed or load conditions as engine damage can occur.
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.