2012 Mustang GT Spark Plugs BURIED in Oil - Here's What Happened
This video documents finding spark plugs buried in oil on a 2012 Mustang GT and diagnosing the cause. The repair centers on removing the ignition coils and valve covers, replacing the spark plug tube seals/valve cover gaskets, cleaning or replacing fouled plugs, and reassembling and testing for leaks and proper operation.
Build Sequence
1. Initial inspection and preparation
Remove the plastic engine cover and visually inspect the ignition coils and spark plug wells. Confirm presence of oil in wells and note how deep/contaminated the plugs/coils are. Disconnect the battery for safety if desired.
2. Remove ignition coils and check plugs
Unplug and unbolt each coil pack, then remove the coils to expose spark plugs. Inspect coils and plug boots for oil contamination and test for ignition issues (visual inspection or use of a multimeter if available).
3. Remove valve covers
Loosen and remove the valve cover bolts and lift off the valve covers to access and replace the spark plug tube seals and valve cover gaskets. Use proper sequence and keep bolts ordered; carefully break the seal and avoid damaging mating surfaces.
4. Replace spark plug tube seals and gaskets
Remove old rubber tube seals and the valve cover gasket. Clean mating surfaces, install new tube seals and the new valve cover gasket. Apply a small amount of RTV only where specified by factory procedure.
5. Clean wells and replace/clean spark plugs
Thoroughly clean oil from the spark plug wells using degreaser and a shop vacuum or absorbent towels. Install new spark plugs (or clean/reinstall if still serviceable) using anti-seize/designed torque and reinstall coils with dielectric grease on the boots.
6. Reassemble and test
Reinstall valve covers and torque bolts to spec, reattach coils and engine cover, reconnect battery if disconnected. Start the engine, check for leaks around valve covers, and verify smooth idle and no misfires. Recheck torque after initial run if recommended.
Frequently Asked Questions
What causes oil to fill the spark plug wells?
On this engine the most common cause is leaking spark plug tube seals and/or valve cover gasket failure that lets oil seep into the wells. A failed PCV or other localized leak is less likely than degraded tube seals.
VIEW FULL ARTICLE →Can I drive the car if the plugs are covered in oil?
You can drive short distances, but driving with oil-fouled plugs risks misfires, rough running, and catalytic converter damage. It's best to diagnose and fix the leak and replace contaminated plugs before extended use.
VIEW FULL ARTICLE →Do I need to replace the ignition coils too?
Not necessarily. Coils soaked in oil should be inspected and tested; if they function and have no internal damage they can be cleaned and reused, but many techs replace coils if oil contamination has caused degradation or persistent misfires.
VIEW FULL ARTICLE →Is this an expensive repair?
The typical parts (valve cover gasket/tube seals and spark plugs) are relatively inexpensive; labor for removing valve covers can make the job take a couple of hours. Expect parts-only costs in the low hundreds and total cost including labor higher if done by a shop.
VIEW FULL ARTICLE →How long will the repair take?
A competent DIYer should budget 2–4 hours for the full job (inspection, removal of valve covers, replacement of seals, cleaning wells, replacing plugs, and reassembly).
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Parts Used (5)
Replaces leaking valve cover gaskets and the rubber seals that keep oil out of the spark plug wells.
Replace any plugs that were fouled by oil; recommended to replace all 8 if contamination occurred.
Used only if manufacturer calls for a small amount of RTV at specific corners; follow Ford instructions.
Clean oil out of spark plug wells and mating surfaces before reassembly.