v6 Engine Ticking

n8bachelor

n8bachelor

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So, I noticed a strange ticking noise coming from the engine yesterday while I was at the drive-thru. It was fast and seemed to increase with the RPMs but there was no hesitation or sluggishness. On the way home tonight the car lit the CEL. There are still no driveability issues but something is definitely amiss.

I opened the hood and listened around and the ticking seems to be coming from the top of the engine. I have a 2004 v6 with 93k on the clock now. I will pull the codes tomorrow at the Zone to get more info.

The noise has me worried... I'm hoping it is something simple like a dirty airflow sensor and not something major like a timing belt/chain/cassette (whatever) or other engine internals.

More to come...
 
OK guys here is the error code I got from the car: http://www.obd-codes.com/p0420

It doesn't seem like that has anything to do with the ticking sound I was hearing. I guess that could be something else entirely. I will keep my ear on that one.

The guy at the Zone offered to sell me some injector cleaner, they really push that stuff. His scanner also indicated a vacuum leak could cause the code to come up (even though it is not mentioned in the online resource). The resource seems to indicate either a faulty O2 sensor or bad cat.

I do not have an scope so is there any way I can make that diagnosis myself or will I have to take it to a shop to have it read / repaired?

Are the O2 sensors easy to locate / replace?

If it is a bad cat those should be replaced under warranty since the car is under 10/100k right?
 
joegr said:
Get one of these and chase down the source of the ticking sound.
http://www.harborfreight.com/mechanics-stethoscope-41966.html

If you've had much misfiring in the past, that could have damaged that cat.
Click to expand...

That's a great price. I will see what I can find. Here's the hard question: what am I looking for? I wouldn't know the difference in sound between a stuck valve, piston slap, or other random tick. Locating the source of the noise should lead to a reasonable diagnosis, right?

I don't know of any misfiring in the past ... except for some rough running one week durring winter 2 years ago. I do run a KKM intake during summer months and it is about time to put the stock back on for winter. Maybe I'll clean the MAF and see if there is any improvement.

I always run premium and maintain the car regularly and have not had any idle or accelleration problems. I know things do break and the Lincoln is no exception. I'll keep digging and look forward to resolving this issue with you guys here.
 
Cats are only covered for 80k or 7 yrs. Regardless of the warranty. The code P420 is the cat and not the O2 sensor. I have had code P420 popping up for close to 2 yrs and have had to other issues. The ticking noise could be an injector.
 
Thanks for the tip on the code Leo. I thought for sure the emissions system was covered for 10/100. I've been wrong before.
I bet a faulty injector could cause damage to the cat. Guess I will have to have those replaced before replacing the cat. Wouldn't the faulty injector throw a code as well? or cause some MPG decrease or drivability issues?
How easy are the injectors to remove/replace?
 
LEOV5 said:
Cats are only covered for 80k or 7 yrs.
Click to expand...
The Federal emissions warranty is 8 years or 80,000 miles. Regardless, he's out on mileage. The 10 year/100K mile warranty extension, AFAIK, only covers the COPs and/or VCGs, and I think it only applies to the V8s.
 
I had a ticking noise on my V6 that was caused by the belt tensioner. Certainly did not sound like a bearing. I believe there is a TSB about it. Good Luck
 
good to know.

my 04 v8 makes cyclic clicking noises on cold start in cold weather. goes away after a few minutes. linc told me it was valve lifters and is somewhat common in (relatively) high mileage AJN engines like mine (115K miles)

what do you think it is?
 
ViC said:
good to know.

my 04 v8 makes cyclic clicking noises on cold start in cold weather. goes away after a few minutes. linc told me it was valve lifters and is somewhat common in (relatively) high mileage AJN engines like mine (115K miles)

what do you think it is?
Click to expand...

My guess would be your secondary timing tensioner.

The oil pressure takes a second to pull it tight when cold.

Also to the OP it could be the same for you. But I dont know about the V-6.

My V-8 threw an o2/cat code when my secondary was shot and then it jumped time one tooth and really started to miss.

Replaced just the secondary tensioner and all codes went away. No need to replace stuff that isnt bad. I would suspect to much slack in the cams would
cause a cat to funk up in just a few trips. :cool:
 
All sorts of suggestions here:
injectors
bad cat
secondary timing tensioner
belt tensioner
vacuum leak
or just a bad O2 sensor

I agree that if timing was off or the injectors were bad that could easily foul a cat.
My dilemma is that the car is running just fine. Wouldn't either of those cause more noticeable problems with day to day driving?
The engine will idle higher for a few seconds when first started, especially on a colder day. This is just to heat the cats to operating temperature and only lasts about 15 seconds and is completely normal for a modern vehicle.

I just paid the car off and don't want to start throwing money at it trying to fix the issue. I'll start with the cheap/easy fix and move on from there. So, how difficult is it to get an O2 sensor out? I would imagine those take some muscle to get loose.
 
Last edited:
Alright.... still no driveability issues, but the ticking persists. From my untrained ear it seems to be coming from the center of the engine (between the V) under the intake manifold. Does that help anyone with diagnosis?
My untrained ear cannot narrow it down any further without a scope. If I don't have to work all day tomorrow I will buy one and narrow that down a bit.
I still think it is odd that the only code stored was the one for the malfunctioning cat.

Any advice is appreciated.
 
n8bachelor said:
Alright.... still no driveability issues, but the ticking persists. From my untrained ear it seems to be coming from the center of the engine (between the V) under the intake manifold. Does that help anyone with diagnosis?
My untrained ear cannot narrow it down any further without a scope. If I don't have to work all day tomorrow I will buy one and narrow that down a bit.
I still think it is odd that the only code stored was the one for the malfunctioning cat.

Any advice is appreciated.
Click to expand...

Nate,

I would get the mechanic's stethoscope and use it. You may find that the noise is coming from an unexpected place and that your engine is just fine, since as you say, it is running properly and all that. It may even end up being in the accessory drive serpentine belt train, possibly, even the water pump. You are not going to get any further without a scope diagnosis, and the thing is fairly cheap.

As for replacing an O2 sensor, they can be pretty tough to remove. I had one of mine break a supposedly unbreakable Blue Point tool, and I needed to chase the threads of the sensor bung on the exhaust pipe before a new sensor would thread in. I replaced both of my sensors in one shot since if one fails, at 151K, the other one is not far behind it. One side came out as expected, the other, came out with some thread material from the bung galled onto the sensor's threads.
 
Is this noise new? Are you sure its not the solid lifter noise you hear? The v6 is not a hyd lifter engine.
 
Honestly, I don't think the noise is new. I always thought the LS engine made some odd noise on the top end. But since I threw the code and heard the noise reflected off the drive-thru wall in close proximity I may have put them together in my mind.
I did buy the scope and began looking for things that may be wrong. I probed around on the top end and did not hear anything suspicious. Granted, I am not familiar with the interior of the engine and didn't really know where to probe. I made several educated guesses about the noise but did not find anything similar through the scope. I probed the heads, intake manifold, and other solid surfaces I could see.
There is much more room around the v6 than the v8 in these cars but I am having trouble locating some things (belt tensioner). All the online schematics I have found for the Ford Duratec 30 engine are mounted transversely so the accessories are all on different.

I'll be happy to post up a pic of the engine if someone can help me search around a bit for possible sources of my tick.
 
Right on the Mark said:
Is this noise new? Are you sure its not the solid lifter noise you hear? The v6 is not a hyd lifter engine.
Click to expand...

No lifters, tappets....



104158348
104158349


The cam acts directly on the tappet shim.
 
Well folks.... Sunday I put my factory air box back on and cleaned the MAS. I also put a bottle of STP injector cleaner in a fresh tank of gas. The MAS had some discoloration that went away with a few squirts of cleaner.
Today when I started the car the CEL did not stay lit. Could it have been possible that the dirty MAS caused the code I pulled from the car? I would have expected a different code than one related to cats or O2 sensor (such as a lean / rich condition) but I'm not complaining. Like I said many times before I never noticed any issues with idle or accelleration, the car runs fine.

Guess the "ticking" was some normal LS noise after all and I was just worked up over nothing.
 
n8bachelor said:
Well folks.... Sunday I put my factory air box back on and cleaned the MAS. I also put a bottle of STP injector cleaner in a fresh tank of gas. The MAS had some discoloration that went away with a few squirts of cleaner.
Today when I started the car the CEL did not stay lit. Could it have been possible that the dirty MAS caused the code I pulled from the car? I would have expected a different code than one related to cats or O2 sensor (such as a lean / rich condition) but I'm not complaining. Like I said many times before I never noticed any issues with idle or accelleration, the car runs fine.

Guess the "ticking" was some normal LS noise after all and I was just worked up over nothing.
Click to expand...

It could be related, or it could be that the P0420 is going to come and go more or less randomly until the cat gets bad enough for the code to stay. Either way, I don't think it's anything to lose sleep over.
 
"You say tomato, and I say...

This is the very first time I've ever found that a shim holder/'bucket' has been referred to as a tappet. When I first started monkeying with engines (flathead days) a 'tappet' was an alternate name for a 'lifter'. And because in a flathead the lifter rides directly on the cam on one end and directly on the valve end on the other, I can see a parallel. But in the AJ-style lay-out, I'll continue to refer to 'buckets'.;)

KS
 
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