Spark Plugs and Wires
Chevy Lumina
Dodge Ram

How do you get to the rear spark plugs on a 1991 Chevy Lumina with a 3.1 V6 engine?

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September 13, 2011 4:21AM

Spark Plugs on a Lumina

Here is advice and input on this job from FAQ Farmers:
  • The engine must be tilted forward.
  • Tilting the engine forward is a pain in the butt and risks breaking/stressing lines/connections. Still a pain, but easier, is removing the alternator. Disconnect the battery. Remove serpentine belt from the alternator by slacking back the tension pulley. Remove the front bolt on the alternator, tilt the alternator back to access the rear bolt. Once alternator is removed, access to the plugs is still tight, but you can reach behind the engine with the necessary tools (you will need extensions for your ratchet wrench) to get to the plugs. Just finished this job about 10 minutes ago. No wonder the car was missing on my 1990. Found gaps to be .055 - .075. For my year and model (3.1 sedan) gaps should be .035
  • You will find when you remove the bolts at the upper mounts(dog bones) their is a hole at the bottom of the mount so when you pull engine forward reinstall bolt thru this hole to hold engine forward. I am a licensed mechanic I own a 90 and 91 lumina 3.1. The proper gap is 60 thousands.
  • Changing spark plugs on Chevy Lumina 3.1 engines or similar: To do this job car must be in neutral. loosen motor mounts. Take bolts holding engine out. at the bottom of right motor mount is a guide hole. the front mounts should be loose so you can raise them. When rear bolts are out take a pry bar or facsimile pull motor forward attach bolt or facsimile to hole at bottom of the motor mount to hold engine in place. When finish installing plugs or whatever it is that you need to get this clearance. You do the reverse to get engine back in position. Remember car must be in neutral to do this correctly.

My own addition: Beware moving the engine may loosen the donut where the exhaust pipe/catalytic converter and manifolds Y pipe meet. You will also need wrench extentions and adapters to allow some "bend" in the wrench. Penetrating oil or solvent is recommended to ensure an easy removal of the plugs. Access is still tight and you may have to feel your way.