Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Motor Mounts and Timing Belt

I purchased a 2003 Nissan Frontier in 2008 with 62,000 miles on it and right now I have just over 78,000 miles on it.

Yesterday, I drove to Aspen, CO and back from Colorado Springs putting about 600 miles on my truck in one day and I got to thinking about my motor mounts and timing belt as it is a very strenuous drive on an engine as you would know if you’ve ever made this drive! As such, I know I will be taking my passat the next time I choose to go to Aspen since the speed limit was 75 mph and I was struggling to get my frontier up to 65 with the pedal floored-yikes!

Anyways, how do i know if my truck needs new motor mounts or a new timing belt? Neither have been done on the truck in its lifetime and I was just wondering.


Motor mounts will often make noise or excessive vibration. If you are concerned, have a mechanic check them, but motor mounts are a very rare problem on most RWD vehicles.

As far as timing belts go, only the V6 engine has a timing belt, and since you said the truck was struggling on the highway, I doubt you have a V6. If by chance you do, that will be in the owner’s manual. At eight years, you will be due, though. The four cylinder does not have a timing belt.

Well a little more info on the truck, its a 3.3L v6 but is SEVERELY underpowered since it is not the supercharged version Nissan offers, and is also 2wd, rear wheel drive.
As for noise and vibration, the truck is very loud and shakey so perhaps my motor mounts are going, or its just a typical small pick-up problem with having a light bed.
But can you see the motor mounts just from looking under the hood? Also, what do signs of wear look like on a timing belt?

This is mostly generic information. I’m familiar with most engines, but not this one specifically.

Timing belt wear is fairly easy to recognize, but it will be behind the plastic covers on the front of the motor. Once you remove them, you should be able to see the belt. Look for cracking, missing ribs, and any other obvious signs of deterioration. At 62K miles, it may be due, anyway. Check the owners handbook for service intervals.

Motor mounts normally last the lifetime of the vehicle, unless you are doing some heavy duty off-roading. They’re are a little more difficult to see, but they’re basically rubber between two pieces of metal. You can look at it and check for cracking, broken off rubber bits and other abnormal wear. If you find damage, then you’ll want to see someone who knows how (unless you do - I’m assuming you don’t because of this post) and replace them. There is also a mount at the rear of the transmission, under the truck. There should be at least one rubber mount there, too.

Vibration is typically not attributed to failing motor mounts, however, unless they’re really shot. If the drive-shaft is multi-part or two piece, check the middle mount for that, too. That’s a more likely culprit…if it exists. Replacing it does actually require some knowledge, not the least of which is because you have to split the shaft, but also because it needs to be loaded (pressure applied towards the front or rear of the vehicle) when installed.

You can also check the universal joints in the drive-shaft. There are at least two, three if it’s a two part shaft.

You may need to even check the wheel bearings. Failing front wheel bearings can cause a lot of vibration, and the same is true for failing rear bearings…and when they go, there won’t be a doubt in your mind. It’ll feel like you hit a 6x6 on the road and the affected wheel will start smoking.

There’s really no reason for any vehicle to vibrate if the tires are balanced correctly. This is normally an indicator something’s wrong, and you should probably find it before it’s drastic.

Hope this is helpful…

Good luck!

Let me and the rest of us in on this “small pick-up problem with having a light bed”. Your timing belt (and others also) will reach the point at which the manufacture says it is due for replacement (either by miles or time) with absolutely no indication that it is due for replacement that is visible to the human eye (other than what it says in the manual). It is not a good idea to extend the manufactures stated lifespan of a timing belt based on a “pass” when inspected visually.If you do go to the trouble of exposing your timing belt and you do see something like a missing tooth, replace it now, but inspection of a timing belt serves a valid purpose only in very specific circumstances, those circumstance being that you own a car with known timing belt issues.

There is one vehicle that GM makes (perhaps the Aveo but I have only read about this problem a few times,I may have the exact vehicle mis-identified,I have never seen one) that has a history of early timing belt failure. This situation is very much removed from the nominal.

This link is to a rather long article where it is stated that visual inspection and detection of a weakened timing belt (even when exposed) is not easy or accurate

Something doesn’t sound right here…Even without a supercharger, a 3.3 V6 should not be that slow.

ha the ride quality in my truck is, well, bumpy to say the least-that is my “small pick-up problem with having a light bed”-it definitely drives like a truck i suppose. And my manual says around 80,000 so it is due soon. I made an appointment for tomorrow so we’ll see!

Keep in mind that it is a crew cab frontier, and I’m at 8,500 feet above sea level. I test drove two and they both felt the same power-wise. I just wish I would have test driven the supercharged model to see the difference!

Have you considered the possibility that the previous owner(s) presumably CO natives, may have beat this truck for 62K miles?
I once looked at a 6 cyl. full size pickup advertised as 1yr old, 20K mi., excellent condition. The truck was backed up to a trailer with small bulldozer. ?Have you towed this with the truck?? I asked. ?No? was the reply. A quick inspection revealed the rear axle had been repaired or replaced. ?Did you have trouble with the axle?? ?No?, again. ?Can I take it for a test drive?? ?Sorry not right now.? I passed. He probably traded it in.

You should consider having the compression checked. It might explain why your truck seems low on power.

Timing belt wear is fairly easy to recognize, but it will be behind the plastic covers on the front of the motor. Once you remove them, you should be able to see the belt. Look for cracking, missing ribs, and any other obvious signs of deterioration.

I’ve seen perfectly good timing belts break 200 miles after the inspection. If there are obvious signs then yes you should definitely replace it…but MANY MANY times a belt shows no signs…and just breaks.

I bought my truck used form a dealership with a complete carfax-I know that carfax doesn’t tell everything, but all the service receipts were in the glove box and it appeared to have a good service history-I by no means bought a crappy car. And the truck is not from colorado originally. It was purchased new in honolulu, shipped to california, then the owners moved to colorado, and sold it two months after they got here. And I had a compression test done before i purchased it by a private mechanic. He also went over the entire truck and did an inspection which revealed no major issues-just small things like new pads and an air filter within the next couple months, all of which I had done immediately after purchasing it. I honestly think it is just an underpowered engine for what it should have in it.

Did the mechanic happen to provide the compression test numbers to you? People routinely post on this forum about compression numbers being good when in reality they are not.
Ideally, on a low miles vehicle like this you should have readings of 180 PSI and up.

Motor mounts and timing belts will not cause a lack of power. Partially clogged fuel filter, partially clogged catalytic converters, slightly degraded performance from aged spark plugs, etc. could cause this.

Since there’s not enough info known about compression readings, codes that may exist, etc maybe this is one of those cases where the vehicle is just anemic in that type of terrain.
Generally there is a 3% power loss per 1000 feet of altitude gain. Do the math on that.
The original owners live in Hawaii and uloaded the car a few months after they moved to CO.
Odds are the power loss is the reason why.

As to timing belt wear there is no way the condition of a belt can be determined by a visual inspection unless there is a blatant problem with it. A aged belt may appear as new and snap the next day.


Of course…but I DID caveat it by saying it may be due now, and to check the manual for service intervals. If the manual says 70, you may be OK for the next 8K miles…but if you look at it, and it’s damaged, don’t wait. If the manual says 50, and it doesn’t look new, don’t wait. There are many reasons to change the belt. We cannot account for every one here. At some point, people have to be semi-responsible for their own actions and decisions. After reading all the suggestions, they have to decide what’s in their best interest. I’ve been fixing mostly my own vehicles for 35 years, and while I did do it as a job for a while, I don’t any more. But, experience still counts, and I’m constantly learning…as I hope everyone else is.

At least that’s the only part of my post you found needed a comment. :slight_smile:

This vehicle suffers from an underpowered engine for this use. It weighs in at over 3500lbs, and the engine is not up to the task at altitude. You probably really had problems driving up I70 from the west to the Eisenhauer/Johnson tunnel. But, you probably also encountered plenty of other vehicles with the same problem.

As others stated, the timing belt was due for replacment at 7 years in your case. Engine mounts are not a normal maintenance item.

Have the timing belt replaced at the right mileage. while it is in the shop have the mechanic check the motor mounts if you are worried about them. Learn some patience,nowhere is it written that every vehicle has to be able to maintain the speed limit on every grade. It is a good thing you didn’t buy the 4 cylinder.

Your 3.3L V6 should be more than capable of highway speeds up to and beyond 75 mph, even on grades. The 180-HP engine should be more than sufficient to keep up with traffic if all is well. This truck should be able to pull 5000 lbs, as stated in the specifications. 75 mph should not be an issue. You probably need a serious tune-up at 78,000 miles. The timing belt should be changed at 8 years, even if the change interval is 105,000 miles. Time to price a timing belt change.