When to Replace Spark Plugs - 9 year old Acura MDX with 102,000 miles

The owner’s manual for our 2002 Acura MDX calls for some major and costly service at 105,000 miles. We are just under 102,000 and the check engine light came on about 50 miles ago on our return trip from the holidays. I plan to take it in this week to inspect the reason for the light coming on. It might be a signal for an oil change (it was last done 5 months ago - less than 4,000 miles ago). I have a note in my car’s file that the 105,000 mile work should alternatively be done after 7 years (well, we are into year 9).

My questions are: (1) How long after the manufacturer’s recommended date would it be safe to defer the spark plug and timing belt work? (Property taxes are due and its Christmas time and we are trying to figure out how to manage all this on one income). The MDX has no symptoms at this time. How much should a 105,000 mile service cost using Acura parts and considering California labor (we go to a discount shop with factory trained mechanics so it costs a little less than at the dealership)? I recall the place we generally have it serviced at told me months ago it is well over $1,000 and close to $1,500 for the labor and materials. We have been pretty good about staying on top of maintenance and plan to keep this car for a good number of more years (it was a fully loaded showroom model).

Thanks, DB of CA

Did you look at the owners manual??

Based on other vehicles of that era…the plugs are probably well past due. And so is the timing belt.

As long as the vehicle is running fine…if money is tight…the plugs can probably wait a little while longer.

The timing belt is a different issue though…This is also the most expensive of the services. Your engine has an interference engine…This means that if the belt breaks…then your engine is toast. If you have any money to spare…then this is where it should go…Instead of buying that 40" LCD TV for the spare bedroom…put the money into extending the life of the car. Can you afford to buy a new car if the timing belt breaks???

There is no “grace period” with the timing belt.
If that belt breaks the engine will be ruined. There will be no warning.
Prudence calls for changing it early.

“The MDX has no symptoms at this time.”

The engine light is on. That’s a serious symptom.
Some auto parts places, like AutoZone will hook up to the engine computer and read the error code(s) for free.
Post the codes here, they’ll look like P0123, and we can offer advice.

Your car has been seriously neglected because the timing belt and spark plugs are 10 years old as the car was likely built in 2001.

JMHO, but spark plugs should be changed every 50k miles at the maximum as there is often a degradation of the plugs even if it’s not noticeable and no CEL has been illuminated. Leaving spark plugs in place this long in an aluminum cylinder head can sometimes lead to thread seizure and this may entail a more expensive thread repair if a problem develops.

As to the timing belt those should be changed at about the 6 year mark when it comes to time so you’re about 4 years past due. After that you’re gambling and since your car has an interference fit engine this means severe engine damage will occur if and when the belt breaks. There will be less than a nano-second of warning if this happens.

A decent independent shop can handle this job as well as a dealer so that’s not an issue.

As to your oil change regimen that may or may not be proper maintenance either based on your 4000 miles reference. How far are you going between oil changes?
If you’ve ever heard about engine oil sludging problems then keep in mind that extended intervals is the reason for that sludging although many car owners like to place the blame elsewhere.

You are looking at about $3,000 to $5,000 for a replacement engine if the timing belt breaks. You are 3+ years past due on this already. Timing belt should be done ASAP if you plan to keep the car.

Spark plugs are due as well and they could be the cause of the check engine light. Plugs deteriorate with time regardless of mileage. The gasket at the base of the plug can get rusty and break down which produces a misfire.

It seems to me you are deferring maintenance and keeping up with very basic items like oil changes. You can save money by replacing the plugs and air filter yourself. If you are not handy at all, then you need to pay someone else. If the motor fails you’ll have a big lump of coal in your Christmas stocking.

To delay the timing belt any further is just plain reckless and inviting major trouble.

The belt and water pump (they go together) will clip your Christmas spending by about $800…

The CEL may be another issue entirely, have the codes read to find out what that is about…

After 9 years and 100K miles, the plugs may be VERY difficult to remove…

While I generally agree with all the above, a lot depends on just what part of California that you live in. If you are near the coast in So. Cal., you do get a bit of a grace period as you don’t have the temperature extremes that you might encounter in the higher elevations or in the northern part of the state. If you live in the dry interior part of the south, that is good too.

Part 2

If you live where it gets below freezing, then you should not put this off, the belt that is. The rubber gets less flexible in cold temperatures and is more likely to break, and you are over the age limit for the rubber. Its the age of the rubber that leads to the belts demise more than the number of miles. But some climates are harder on rubber than others. It will last longer in a dry mild climate than in a high humidity climate with temperature extremes.

Part 3

Do look at the dealer for this service, sometimes they have specials for the timing belt, oil seals and water pump package. You want to do all these at once. At least get a quote from the dealer.

As for the plugs, you need to check your owners manual for the service interval. It will likely occur at 30k if regular plugs are used, 100k if platinum plugs are used, or 120k if your vehicle came with Iridium plugs. I would not worry about the plugs seizing in the head as they were plated with an anti-seize coating when installed.

Part 4

Un fortunately, AutoZone will not read your codes for you in California, which is odd for a state that touts itself for consumer protection. You could ask though, your local AutoZone might do it anyway. For the cost of having the codes read, you could probably buy a simple code reader at AutoZone and they would show you how to use it, then you could post the codes here and we will be happy to help you understand them. Just post the actual code, not what someone else tells you it means.

You do not need an Acura specialist or dealer to perform the work. Your engine is shared by Honda V6 models.

In your shoes you do need to budget for this major maintenance item sooner rather than latter. Folks are correct there is timing belt risk involved but really there was a few years back. Spark plugs are not a risk though of major damage.

The check engine light is not serious unless flashing. I own a newer 2007 MDX and have had my check engine light go on but then go turn off a day latter two times. You can wait a few days and see if it turns off. My MDX actually shows the code in the related code in the Navigation screen. Not sure what they did back in 2002.

If you feel that the time factor in your maintenance schedule can be completely ignored, then I’m curious why you feel that the mileage factor should be believed. Anyway, if your timing belt breaks, which is a reasonable possibility at this point, you’ll be throwing away maybe $3,000 or more on a new engine. That’s a lot of Christmas presents.