Odd rattling noise

[rcmaniac791]

Occasionally over the last 2 or so years, I'd hear this metallic rattling sound coming from the front of the 318. I didn't really think much of it, since the car runs fine, and the noise is intermittent. But here recently, the noise is becoming more noticeable. It kind of sounds like that penny that gets in the dryer and tumbles around With the clothes.

So my first instinct is.....crap....timing chain. But the car only has 67,000 on it, and is not driven like a racecar. Lots of highway miles. It also runs totally fine. No hesitation or anything. I also popped the distributor cap off to check slack, and there is only 1-2 degrees of play.

So could it be water pump bearings? Fan clutch? I do know that when I go anywhere near the throttle, the noise goes away. (Or I just can't hear it over the engine)

Any advice would be appreciated, and I can post a video of the noise if it would help.

 

[Kernel Sanders]

My bet is the brake dust shield... I know that sound

 

[AJ/FormS]

Go check the chain properly at the balancer.You cannot check chain slack from the dizzy.
But I've never heard a Mopar chain hit the cover; they are not like chebbys.

My money is on the alternator bearing, or brushes, or both.

 

[rcmaniac791]

My money is on the alternator bearing, or brushes, or both.

I replaced the alternator 4 months ago. It doesn't have 5000 miles on it. I hope that's not it. I'd think that the timing chain would cause drivability issues as well. I'll have to start it and just listen closely.

 

[AJ/FormS]

Easy test: next time it's noisy,just flip off the belt!
While you're down there sawing on the balancer, you might as well check the retaining bolt. If it has come loose, I suppose it is possible for the balancer to migrate forward, allowing the oil-flinger back there to rattle. I suppose.
When the water pump goes, it is pretty obvious, it starts out continuously growly.
One more possible source is the fuel pump. Sometimes the return spring inside fails and then the eccentric starts slapping the pump arm. But Im still betting on the alternator bearing. I have heard that sound hundreds of times.
Do you know how to test for a wrist pin noise?

 

[JerryH]

Water pump. Mine had just shy of 50tmiles on the clock and it started leaking. Prior to that it made the same noise. I did this a week ago.

 

[BudW]

You can run an engine a short time without a drive belt on the water pump – for testing purposes.

Been my experience is one you have drive belt(s) off, just rotate the item (water pump, A/C clutch pulley, alternator, etc.) in question and/or check for up-down/in-out play, and in most cases the problem will be apparent (if problem there).

The fuel pump arm only touches the eccentric ring when fuel is in demand, otherwise fuel pressure pushes the arm away from eccentric a bit.
I've seen broken fuel pump housings and arms. I've also seen worn eccentrics as well as loose camshaft screws.

The right exhaust manifold valve can be loose or broken. Some of ours have a thermostatic spring that controls exhaust valve operation and others use a vacuum motor to operate the valve – and have seen the vacuum motor linkage that can be broken or missing.

Broken valve train components might also be a suspect (broken valve spring, broken rocker arm, a bent pushrod and so forth.

If the harmonic balancer ring has came off of its hub, the outer ring will rub up against the engine and can make a noise. you can see this when engine is running by looking at the balancer.

Also, I have even seen cracked flexplates cause weird and intermitant noises, at times.
BudW

 

[rcmaniac791]

Sweet. Lots of good info

I popped the hood when I got home today from work to see if I could pinpoint the noise, only to find absolutely nothing. everything was running perfectly fine. Nothing strange at all. I guess if it comes back, I'll go ahead and pull the belts.

Do you know how to test for a wrist pin noise?

I don't think that's making the noise, but it would be nice to know how to check it.

The fuel pump arm only touches the eccentric ring when fuel is in demand, otherwise fuel pressure pushes the arm away from eccentric a bit.

I replaced the pump about 5 months ago.

Also, the engine runs too well to have broken valve train components. I've driven cars with broken springs, and it's not pretty.


If the noise comes back, I'll keep y'all posted.

 

[AJ/FormS]

I didn't mean to imply that your noise was a W-pin, cuz that noise is never intermittent.It's either clicking, clacking or hammering.In the very beginning stages if you catch it, it makes the noise continuously,and the noise keeps pace with the engine rpm; except for a a few microseconds, when the engine changes from revs climbing to revs falling.At this time the noise becomes noticeably quieter.Under load it can hammer pretty bad shortly after. So it goes from just perceptible to noisy to hammering in a short period of time. The noise has a different timbre than a rod and if you don't catch it early, then it is unmistakeable on account of it is kindof a double click/clack, as the noise occurs each time the piston changes direction. Whereas when a rod starts making noise it is a single loud knock at every ignition event, perhaps followed by a much quieter knock when the piston transitions from exhaust to intake.Many times this second noise is eclipsed by other normal engine sounds. As it gets worse the second noise also becomes markedly more noisy.
I highly doubt either of these are your issue.

I'm sticking to the alternator bearing, probably the rear roller is dry.You may be hearing the little roller cage vibrating against the rollers or armature. This is an easy fix. Pop the brushes out, pop the back cover off, lay in a dab of waterproof grease, and slam it all back together.About an hour in a warm workspace.

 

[rcmaniac791]

I didn't mean to imply that your noise was a W-pin

Yeah I gotcha. I haven't driven the car in awhile because it's been so blasted cold and snowy. There's also salt on the roads now.....never a good thing. But when I was running it the last few times, I haven't heard the noise.

 

[rcmaniac791]

Noise came back today. Popped the hood to have a good listen. Stood on one side of the motor, then the other.

Pinpointed that it's certainly one of the front accessories, and nothing mechanical in the motor. (Yippee!)

So, I thought it was the alternator, listened really close to it, put my hand on the back of it to feel any weird vibrations......nothing. It's silent, which is good, because I just replaced it. Moved to the other side, listened to the air pump, felt the back of that, and it rumbled a little, so I proceeded to take that belt off, but the noise still remained. The more I listened, it sounded like the middle of the accessories, like the water pump. I didn't feel that while running because of moving belts, etc. (I've been hung up in a moving belt before, and got very lucky. Story for another post) The A/C compressor is the same: no weird vibrations or ticks.

Anyway, with the motor off, I started wiggling pulleys. Alt was fine, A/C was fine, P.S. was fine, Air pump was fine, but the water pump pulley/fan had a good amount of visible movement. No coolant leaks, and the car doesn't run hot, so I think it's good enough until I can get home in about 6 weeks to replace it. If I have to do a parking lot install here, I can; but I don't want to if I don't have to. I know that the water pump is original.

So what have y'all used for w-pumps? I was looking at a Milodon. The Edelbrock is waaaaay too expensive, but I also don't want to risk it with a cheap 20-30 dollar pump. Same question for coolant, what works well, and what doesn't?

 

[AJ/FormS]

I recycle used ones so I'm no help. I still have a few 197xs pumps kicking around.
On my performance car, I have a Milodon hi-volume, but that would be overkill,I think, for you. Its been on there for a really long time, maybe 14 years?

 

[Justwondering]

in 2016 I replaced the water pump on my F-350 dually with a rockauto middle price unit. Have hauled 6 or 7 loads at 8,000 pounds or more in 100F+ weather with no problems.

Chrysler has only had the a/c system renovated ... nothing involving water pump yet.

 

[rcmaniac791]

Found a Standard duty milodon aluminum water pump at Summit for around $60 with shipping and everything. Seems reasonable to me.

Its been on there for a really long time, maybe 14 years?

That's what I like to hear.

 

[AJ/FormS]

Well then you'll like this;
Over 100,000 miles

 

[BudW]

I would recommend looking for a water pump that’s snout looks like this.

This style will work, but the style above has a larger shaft and larger bearings in it.

Go new, if you can afford it.
BudW

 

[rcmaniac791]

New is the only option as of now. I have a good job, so I can afford it.

Here's what I was thinking of: 1984 CHRYSLER FIFTH AVENUE Milodon Mechanical Water Pumps 16350


I may put a new thermostat in it too, while I'm at it. I've already had it replaced once by another shop, but that was before we knew that they were kind of sketchy.

 

[BudW]

How about something like this (with lifetime warranty on the part)?

The thermostats on these cars don’t go bad that often.
If the thermostat housing is not leaking, then I’d recommend leaving it alone.

Be sure to either get 50/50 pre-mixed coolant or purchase some distilled water and 100% coolant and pre-mix your own (50/50%).

(Personally I don’t see paying for 50/50 pre-mix for same $ (apx.) per bottle as the 100% stuff is, when distilled water is about $1 (US) per gallon . . . but that is just me).

BudW

 

[rcmaniac791]

I didn't know you could get them that cheap. sweet.

As far as coolant, I'm just going to mix my own. Any tips or tricks with bleeding the cooling system?

 

[BudW]

Our cars don't have an official bleed procedures (I don't think) for the cooling system is the older simple style. The heater core is highest location (on purpose) in cooling system – but water pump will automatically push water through it – so as long as HVAC system is not in “off” or in MAX A/C mode – so no worries there.

If you are worried about it, then park car at angle (nose up) for final top-off – but even that is not needed.

Once radiator neck is full, then make sure coolant bottle is within the marks. Normal driving will take care of any/all air bubbles after a couple of weeks.
BudW