2007 Mercury Mountaineer ticking under the hood

My parents have a 2007 Mercury Mountaineer, 100,845 miles. They change oil like a religion. It has under the hood ticking that increases and decreases with RPM. The ticking (tickity-tickity) sounds like when there is low oil. People have said,"You better put oil in there…"The oil is full. I can’t tell if the sound is coming from inside the engine, or if something on the engine might be loose that is causing the ticking as the engine RPM changes. From what I can remember from auto shop in the 80’s…it kind of sounds like valves/lifters.

Also, it has a strange road noise that I think is coming from the tires. It sounds and sort of feels like riding on knobby off road tires. I can put it in neutral and turn off the engine, and the noise remains and decreases as the speed does, so it is not from the engine.

Anyone have any ideas? Thanks in advance.

I’m assuming your folks have actually checked the oil when the ticking occurs. How old is the serpentine belt? Try spraying some water on the belt to see if the ticking stops.

For the road noise, does the pitch or volume of the sound change when the steering wheel is turned off-center? This indicates one or more bad front wheel bearings.

Ed B.

I am currently driving it while my truck is getting the rear end replaced. I just went outside and checked the oil. Exactly on the top of the fill line, oil looks clean, but is ticking. This weekend I will hose the belt with water, experiment with the steering angle for the road noise, and report back. I know for a fact the serp. belt is original.

Well, it stopped raining so I decided to pour some water on the serp. belt. No change. Thought maybe the radiator fan was clipping the plastic shroud, but didn’t seem so. I took a picture of the area where the ticking is the loudest. Passenger side of the engine compartment and seems to be coming from inside the engine.

Those are your injectors. Take a piece of hose and put it in one ear and listen for the clicking. Move from one injector to the next until you find the culprit. The serpentine belt and tensioner need replacing. If this car has a timing belt it needs doing too.

Thanks knfenimore,
I am a first responder/former EMT so I will take my stethoscope out of my kit and check things out. I never thought I would ever use it on a vehicle. :slight_smile:

Injector tick is pretty loud and very easy to hear with a stethoscope. So you will easily hear all of them ticking. The question will be whether or not they all sound about the same (and about the same as the ones on the other side).

But injector tick is normally not bad enough to raise any eyebrows or make a racket audible above everything else. My own guess is - because I think this has hydraulic valve lifters (lash adjusters) - that you have a collapsed lifter or two.

could it be an exhaust leak?

Where ever the leak is, the stethoscope will help you isolate it. When you find the noise post back and we can help more.

Could be a collapsed cam follower . . . also known as “lifters”

Substitute 1 quart of engine oil for 1 quart of Rislone

Please report back with results

db4690’s suggestion is a good one, IMHO.
Or, alternatively, the OP could add a can of Seafoam to the motor oil shortly before the next oil change.

The cleaning power of the Seafoam could correct a lifter problem, but I would suggest not driving for more than…maybe 100 miles…before changing the oil. Even if it doesn’t help, it won’t hurt anything.

edb1961, on the road noise, turning the wheel to the right for lane change causes it to get quieter. More so on a hard right lane change. No difference when turning or drifting to the left.

If the noise happens on a right turn, I believe the left wheel bearing is going bad. The right turn puts more stress on the left wheel bearing. If I’m wrong I’m sure somebody will correct me.


Short of finding a large empty parking lot and driving in fast tight circles, it seems the harder the right turn the more quiet it gets. Left turns no change that I can tell. I’ll also wait for others.

Please let us know what happens with the Rislone

This may not be of much help to you OP, but my early 90’s Corolla has had a slight ticking noise heard only at idle for the past 10 years. I used a garden hose to isolate where it is coming from, and it’s the alternator.

Front wheel bearing, one side or the other my guess. Any mechanic worth their weight and in ownership of a stethoscope will be able to deny this as a cause, but my wag! If you are driving down the road and turn severely (not enough to crash) and the noise varies, confirmed in my book. The ticking might be from a bad idler pulley

db4690, the vehicle is actually due for an oil change. The dash indicator just popped saying it is time. I would change the oil and filter myself, but I don’t have any clue how to reset the indicator. Since the oil is full, I figure adding seafom or Rislone would over fill it.

The owner’s manual should tell you how to reset the light. I can’t give you the exact procedure, but is quite easy and is done through either the menu on the trip odometer or through the message center if you have one. If you don’t have an owner’s manual you can probably find a pdf online and I would spend the time to do it.

You don’t even know if the noise is valve noise yet, so personally I wouldn’t dump anything into the oil - other than oil.


Here’s my advice

Bring the car to your usual mechanic or shop for the oil change

Ask them to substitute one quart of oil for one quart of Rislone

Have them reset the oil change reminder

Please report back on the ticking noise