The Chrysler Minivan Fan Club Forums banner
1 - 20 of 35 Posts

·
fix it if you can
Joined
·
5,748 Posts
Impossible to say without knowing how many miles it has or what kind of use/abuse and service it has seen, but if it has had regular service and is under 150 kmi, I'd suspect a possible broken valve spring (which would make the noise louder from one valve cover vs the other)
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #3 ·
Thanks - I should probably get a mechanic's stethoscope to help pinpoint the location. Previously the noise was intermittent - it would make the sound one day then go four or five days without making any unusual noises. The past couple of days it has been constant.
 

·
Registered
Joined
·
299 Posts
Sounds similar to a rod knock to me, but that is unlikely unless high(very) mileage or there were lubrication issues at some point. Stethscopes have been sketchy for me, sometimes great other times useless....still pretty cheap way to look around. I've never had a valve spring break, just somehow dodged that little bullet
 

·
Registered
Joined
·
2,994 Posts
Thanks - I should probably get a mechanic's stethoscope to help pinpoint the location. Previously the noise was intermittent - it would make the sound one day then go four or five days without making any unusual noises. The past couple of days it has been constant.
You can use a length (carefully) of garden hose to help narrow in on the source of engine noise. One time when visiting mom over december holiday, I used a wrapping paper tube to identify a bad APD
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #7 ·
Sounds similar to a rod knock to me, but that is unlikely unless high(very) mileage or there were lubrication issues at some point.
It is high mileage (229.000). Low oil pressure at idle became a problem at 226,000, so now running 10w-49 to maintain oil pressure.

I am going to drive it until the engine fails. Body and especially rocket panel corrosion makes repairing or replacing the engine financially impractical.

The engine had been quiet until a couple of weeks ago. I am not surprised it is getting noisy, I just wondered what the noise is.
 

·
Registered
Joined
·
1,547 Posts
It is high mileage (229.000). Low oil pressure at idle became a problem at 226,000, so now running 10w-49 to maintain oil pressure.
was it actual low pressure or just the sender unit complaining?

9/10 times on these vans the oil light is just the sender unit going bad

there's also an o-ring on the oil pump pickup that should be replaced, it begins to weep and then oil pressure is decreased, and air enters through it
 

·
Registered
2006 Dodge Caravan SXE
Joined
·
1,227 Posts
I recorded this with the microphone above the the upper intake. The first ten seconds are with the engine at idle, then I revved it a few times. It is a 2007 3.8L.

Thanks for any ideas on this.

2007 Dodge Grand Caravan SXT 3.8L Engine Noise
To some degree it sounds like bad ignition wire(s) or a plug electrode got damaged do to the engine missing sound.

Also do as FabiGATOR said, run the van without the accessory belt on for a little bit to see if the noise just goes away. It would rule out power steering, water pump AC, alternator, idler pulley, belt and the smog air pump.

I also detected an air hissing sound.
 

·
Registered
Joined
·
299 Posts
It is high mileage (229.000). Low oil pressure at idle became a problem at 226,000, so now running 10w-49 to maintain oil pressure.

I am going to drive it until the engine fails. Body and especially rocket panel corrosion makes repairing or replacing the engine financially impractical.

The engine had been quiet until a couple of weeks ago. I am not surprised it is getting noisy, I just wondered what the noise is.
I wouldn't call that particularly high mileage and as mentioned earlier, the oil pressure sending units are crap and seriously misleading on these engines, I'm on my third and the next one will be a butt plug, fed up with the poor quality. My oil light had me very worried until I pulled the valve cover when stranded with the low warning and saw more than enough oil flow when the eng was running. I do understand the economics of your reasoning, I'd do the same.
 

·
Registered
Joined
·
973 Posts
I hear what seems like clatter similar to when my pick-up tube o-ring was allowing air to be pulled in with the oil; however, there is also some other sound during revving that I don't recognize...

Pick-up tube to block/pump interface is above oil level in the pan, so if this o-ring fails to seal properly then you end up pulling air in with or instead of oil. O-ring should be replaced whenever the oil pan gasket is replaced and the OEM sells a kit with both the oil pan gasket and o-ring in one package. Highly recommended...
 

·
Registered
Joined
·
2,994 Posts
The alternator decoupler pulley can sound like a bad engine knock... made mine sound like a diesel engine,

Remove the belt and post another recording.

AutoZone has a great 'Loan a Tool' program that you use a credit card and if you return the tool within 90 days (three months!) they give you a full refund...

I would go and borrow their serpentine belt tool. It makes removing the belt easy peazy...


Video link borrowed from JeepMan post... haha
 

·
fix it if you can
Joined
·
5,748 Posts
If it went without oil pressure, cam lobes and lifters are likely the cause of the noise, if it's not throwing misfire code(s) it will probably start soon.
 

·
Registered
Joined
·
185 Posts
Discussion Starter · #16 ·
I will remove the serpentine belt and see what difference that makes.

The van was due for an oil change (3000 miles since the last change), and this time I used 5w-40 oil. Specifically Quaker State full synthetic, a Fram Ultra Synthetic filter, and a can of Liqui Moly Hydraulic Lifter Additive. The noise has diminished dramatically (rough guess here, by 90%). I am not sure if it was the oil change or the Liqui Moly product that made a difference. Or maybe neither, because previously the sound would sometimes come and go without any intervention from me. I still hear a ticking sound, but it is much, much quieter. The light ticking stays in sync with engine RPMs - it ticks faster or slower as the RPMs vary.

The first start after changing the oil in this vehicle always resulted in a slight knocking sound for a few seconds until the oil started circulating. Two months ago, I started noticing that sound anytime the van had not been driven for 8 - 10 hours. Maybe that is a symptom of a failed oil pick-up tube O-ring.
 

·
Registered
Joined
·
973 Posts
Might have been the oil change... likely raising the fill level, assuming your engine uses oil over time like most of the 3.3/3.8 motors do. With the leaking pick-up tube o-ring seal on my 3.8L, oil level in the pan would make a significant difference on the amount of valvetrain chatter present at any given time. Also played around with slight oil viscosity changes and filter changes that made notable differences but never quite totally knocked the chatter out by doing so.

Prior to discovering the issue with the pick-up tube o-ring, one of the things I did to net the best chatter reduction was to keep the oil level over-filled by approximately 1/4 of a quart (just a bit above the full level on the dip stick)... not that I would normally recommend over-filling though, as all manufacturers warn about possible negative consequences of doing so; however, I got away with it.

Ultimately, problem was totally resolved on mine by replacing the pickup tube o-ring, which I found to be hardened (more like plastic than rubber) and easily/readily sliding up/down on the pickup tube with little resistance... and thus sealing poorly. Once I replaced the old hardened o-ring, all chatter went away and I've gone back to using 5W20 at normal levels and standard size/spec filters without any issues.

Here's a link to the OEM kit including both the oil pan gasket and pickup tube o-ring in a single package:


Personally, I would recommend replacing this o-ring whenever the oil pan gasket is replaced... it's pretty easy to do at that time as you've already got the pan off. Unfortunately, many folks are not even aware of the existence of this o-ring...
 

·
Registered
Joined
·
96 Posts
I will remove the serpentine belt and see what difference that makes.

The van was due for an oil change (3000 miles since the last change), and this time I used 5w-40 oil. Specifically Quaker State full synthetic, a Fram Ultra Synthetic filter, and a can of Liqui Moly Hydraulic Lifter Additive. The noise has diminished dramatically (rough guess here, by 90%). I am not sure if it was the oil change or the Liqui Moly product that made a difference. Or maybe neither, because previously the sound would sometimes come and go without any intervention from me. I still hear a ticking sound, but it is much, much quieter. The light ticking stays in sync with engine RPMs - it ticks faster or slower as the RPMs vary.

The first start after changing the oil in this vehicle always resulted in a slight knocking sound for a few seconds until the oil started circulating. Two months ago, I started noticing that sound anytime the van had not been driven for 8 - 10 hours. Maybe that is a symptom of a failed oil pick-up tube O-ring.
You see, you just cleared the unseen factor, that knocking at startup, IS a sure sign that the crankshaft bearings are worn, and are now giving you that warning. My friend, it isn't going to go away. It will get worse. Before I bought the 2015 Town&Country with 64k, I checked a 2014 that my wife sorta fell in love with, it had 156k, and as soon as I started it, I heard the crank knocking and then simmered down. I knew that engine was done. I am pretty sure you understand, the pistons are attached to crank with bearings in-between. Thru poor engine maintenance those bearings wear badly.

Listen, I don't know what is the mileage on your engine, but you might (at least) drop the oil pan and replace the bearings. It can be done,. Then try seeing if there's a change in performance. In MY opinion, my choice, if the body is without rust, in great condition, I'd just drop another engine with low miles. That's just me.
 

·
Registered
Joined
·
862 Posts
I recorded this with the microphone above the the upper intake. The first ten seconds are with the engine at idle, then I revved it a few times. It is a 2007 3.8L.

Thanks for any ideas on this.

2007 Dodge Grand Caravan SXT 3.8L Engine Noise
four years ago i had very similar sound or maybe exact, i described it at the time as a diesel truck sound--i put a new pulley on the alternator sound gone

I took the serpentine belt off the pulleys in van just to test if sound went away. it did..that brought me to the idea that it was the pulley..
 

·
Registered
Joined
·
2,994 Posts
four years ago i had very similar sound or maybe exact, i described it at the time as a diesel truck sound--i put a new pulley on the alternator sound gone

I took the serpentine belt off the pulleys in van just to test if sound went away. it did..that brought me to the idea that it was the pulley..
I will remove the serpentine belt and see what difference that makes.

The van was due for an oil change (3000 miles since the last change), and this time I used 5w-40 oil. Specifically Quaker Sta...
I anxiously await kc27's reply and report.
ADP would certainly not surprise me either.

A lot better than scrapping the van or doing an engine swap.

What would have been better than a recording would have been a video (with sound) and moving about the engine so others could hear and see where it was 'more pronounced'

There also may be a combination of sounds and everyone hears something different.
 
1 - 20 of 35 Posts
Top