Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Changing Spark Plugs on an Altima

I am wondering how difficult it is to change the spark plugs on a 2003 Nissan Altima. I am not a car expert by any means, but have some experience in working on cars (but mostly Honda’s). Should I not even bother trying to do it myself and just take it somewhere? Are there any guides I can look at that gives instructions step-by-step? Any suggestions??

Is this 4 cyl or 6?

If the car has the 2.5L four-cylinder engine, it’s pretty simple. Pull off the plug wire boots, remove old plugs, install new plugs, reattach wires, and off you go.

The 3.5L V6 engine, on the other hand, might be more difficult. You’ll have three plugs in front (easy), but the three in back could be a pain in the butt to reach.

Spark plugs are generally one of the easiest jobs one can do on a car. For instructional assistance, consult a Haynes/Chilton’s repair manual at your local library (or buy one from an auto parts store), or go onto and pull up the repair guide for your vehicle.

Spend $15 - $20 for a Haynes manual for your car. It will pay for itself many times over during the life of the car if you are doing your own work.

its a 4 cyl - 2.5 L.

You should have no difficulty replacing the plugs on this engine. Remember to put a little anti-sieze compound on the threads of the new plugs before they’re installed.


I seem to recall reading that using anti-seize on spark plugs is a bad idea because it can throw off torque accuracy, if you’re using a torque wrench. Any sense to that?

I believe what you’re talking about is, never apply anti-seize to wheel lug studs or bolts. This can result in false torque readings which can fitigue this hardware with repeated removal/installation for other services. And these readings are in ft-lbs.

On sparkplugs, the torque specs are in in-lbs. And with anti-seize on the threads, you’ll get a truer torque reading because it acts as lubricant as the steel threads on the sparkplugs are screwed into the aluminum threads in the head.


JMHO, but I never use a torque wrench on spark plugs. The odds of a torque wrench (especially the typical 1/2" drive type) may be notoriously off at low specs.
I run tapered seat plugs down to finger tight + a bump snug (1/16 turn) and gasket seat plugs down to finger tight + 1/4 turn. Never had one leak, loosen, or strip yet although I’ve had to repair a lot of stripped ones.

It seems like when a subject like this came up a while back I looked at the NGK site and they gave torque specs in ft. lbs.
Fuzzy memory makes me think some of those specs were in the 15 ft. lbs category on tapered seat plugs for aluminum heads and this kind of makes me cringe a lot.

The torque specs for tapered-seat spark plugs is 15 Of course, we know that few people will have and use a torque wrench.
Put a little anti-seize on the spark plug threads. Turn the spark plug in by hand. Snug the spark plug. DON’T tighten it like you would tighten a bolt. Only snug it. This would easily be 15 ft. lb.

And if you did have a torque wrench that reads ft-lbs, the minimum torque setting on these type of torque wrenches is 20 ft-lbs. So you can’t even measure 15 ft-lbs with one of these torque wrenches. But if you did want to torque the plugs to spec you would need a torque wrench that measures in in-lbs. In this case, the torque for the plugs would be 180 in-lbs.