Engine Knock??

[James AKA Lynx]

An engine knock started about 500 miles ago in the middle of a 1000 mile trip and I have not been able to get rid of it. I have done a lot of things and then engine sounds much better. I still have an uneven idle. goes up and down a little. The knock is noticable when accelerating and when putting in gear. Not when cold.<br><br>Strange. <br><br>Suggestions?<br><br>James AKA Lynx

 

[MrNoodly]

How many miles on your vehicle?

 

[James AKA Lynx]

118000 miles

 

[David]

I'd suggest just stopping by 1 or 2 local mechanic's shops and let them see what it is. They aren't going to charge you just to tell you what it is. A mechanic is going to know right away if it's a crankshaft related engine knock or something else less catastrophic.<br><br>Just act like you want a quote on a repair and see what they say..

 

[James AKA Lynx]

David- Not going to happen. I will do the work myself. I have already corrected a lot. The Mechanic's cannot say untill they tear the engine apart or put it on expensive machines. And then they will do what they want and change me what they want. I just do not know an honest mechanic here.

 

[wrcsixeight]

The timing chain could be stretched, and allowed it to skip a tooth, now the timing is out, and pinging under load.<br><br>Pinging is very hard on the engine. &nbsp;Some higher octane fuel will help this, if the noise is indeed pinging and not a rod knock.<br><br>You said there was play in the distributor, rotational play might indicate timing chain stretch.<br><br>Not hard to change, just make sure to take notes where each bolt comes out of hole and through which bracket.<br><br>Taking the fan off the waterpump is the bigger headache on magnum engines, and might as well replace the water pump when in there.<br><br>If you do go there.<br><br><br>

 

[James AKA Lynx]

This engine has a metal timing chain and does not have a history of slipping a tooth. Stretch a little maybe. I have been told that the amount of distributor play would not cause the knock.<br><br>My engine does not have an ERG Valve. Nor an anti-knock valve/electronics.<br><br>Any other ideas? Anything, let me know.<br><br>James AKA Lynx

 

[David]

Lynx, I wasn't suggesting have the mechanic do the work.. I was meaning get him to tell you what's wrong with it, then you know what to fix.

 

[highdesertranger]

james give us some more info.&nbsp; what type of engine and what year?&nbsp; can you feather the knock(make it get worse or better with the gas peddle)?&nbsp; you said it gets worse when putting it in gear.&nbsp; try this out step on the brake,&nbsp; put it in gear and give it some gas don't let it move.&nbsp; you are putting the engine under a load.&nbsp; does it get worse or better?&nbsp; does it not knock at all sitting and idling?&nbsp; try to isolate.&nbsp; take a piece of hose 4ft or so, &nbsp;use it like a stethoscope.&nbsp; make sure you check all over the engine where is the noise the loudest?&nbsp; check&nbsp;the trans and bell housing too.&nbsp;you also said you drove it 500 miles&nbsp;was it was knocking the whole time?&nbsp; also has the engine sat for any length of time before the knocking?&nbsp;&nbsp;where are you at?&nbsp; &nbsp;highdsertranger

 

[wrcsixeight]

Over on the dodge forums there are a number of incidences of 3.9, 5.2 and 5.9 engines that have skipped a tooth on the timing chain anywhere in the 100k to 160k mile range. &nbsp;Usually the chain can be heard slapping the timing chain cover though and a lack of power and very poor running is occurring too.<br><br>Any DTC's stored in the computer?

 

[James AKA Lynx]

David - no offenses taken. I am on another forum and have gone through what they have said and it is still there. I need to take a longer path and that means getting a manual and my figures dirty. Pluse some hours of work. Unless I can find a quicker fix.<br><br>3.9 V6 gas, 1997 with 118000 miles. It did sit for about 3 years before I bought it and the oil was VERY bad when I changed it. Which has lead me to believe that something dislogged and setteled into a lifter. However if that was so then it would have knocked during at first start when cold. <br><br>When the engine is cold there is no knock, even when driving.BUT - After warmed up some, Mostly the knock is not there at idle unless I rev the engine some and then it starts and then goes away. Oil pressure gauge inside van says normal.&nbsp; The knock is there a little at idle and some metal rattling as well after rev'ing a little. Having the doghouse off makes the noise worse. The knock is almost non-existent when at a constant speed and flat roads. When giving more gas, the knock is there. I cannot say if it is louder but more often.&nbsp; It is not knocking at idle after warmed up. IF I do not give it some gas. When taking it out and returning it is knocking for a little while and then quiets down. After a while there is no knock under revs.<br><br>I am the only one driving it. I have been with it before and after the knock started. I had a check engine light, uneven idle, and replaced bad vacuum hoses.Did some other things and smooth out the engine. Sounds much better except for the knock. 6000 miles ago, it used to have a knock when starting. No more. I haed the engine oil changed and it was overfilled. I took out a quart and it was very dark. I may send it off to be tested or get a flush. Does not use any oil. No extra air comming out PVC valve. No white, water, coming out anything and no water leaks. <br><br>I have not done compression test, oil pressure test nor taken off valve covers. No oils texted.<br><br>I am in SE Texas, SE Houston area is where I am living right now.<br><br>Let me know if you would like anything else.<br><br>James AKA Lynx

 

[wrcsixeight]

Lifters make ticking sounds, not knocking. &nbsp;The oil filter, and its anti drain back valve can effect the volume and duration of start up ticking. &nbsp;Filters with a silicone ADBV are better at preventing ticking on start up.<br><br>Do not do an engine flush. &nbsp;To clean it, do more frequent changes with a good high detergent oil like Shell Rotella.<br><br>Some say Marvel mystery oil is good at slow cleaning. &nbsp;A fast flush type product can loosen things enough to lodge in the oil galleys and cause oil starvation and complete engine failure.<br><br>You tube has a bunch of examples of ticking lifters, rod knock, and pinging.<br><br><br>

 

[James AKA Lynx]

my engine has ticking lifters.<br><br>James AKA Lynx

 

[highdesertranger]

so are you saying it's a lifter tick?&nbsp; not a knock.&nbsp; highdesertranger

 

[James AKA Lynx]

IT is a lifter tick. I listened to the utube vid's and the only sound was a lifter tick that compared. <br><br>So it is the lifter. One person took off the valve cover and sprayed carb cleaner on the lifter to unclog it. It worked for him. (and motor flush) I need to get a 4 foot hose and find the bad one(s).<br><br>Thoughts?<br><br>James AKA Lynx

 

[BamaDuke]

I have a Dakota with the 3.9.&nbsp; It has about 190k on it now, and I gave it to my daughter.&nbsp; It, too, has a bit of lifter tick during the summer, running the AC.&nbsp; I changed the oil every 4000 since it was new, and it only let me down once, the crank position sensor.&nbsp; I would do the Marvel Oil for a couple of changes, then bump up the oil viscosity.&nbsp; You could also try STP or Lucas oil treatment, they have better adhesion both inside and outside the lifters.&nbsp; If it quiets down, you're probably in the clear. A rod knock wouldn't have lasted 500 miles with a load, without making itself known <img class="emoticon bbc_img" src="/images/boards/smilies/biggrin.gif"><br><br>On a somewhat related note, we had a rod bearing failure on a Ford F150 last fall.&nbsp; It was our gold claim rig, 4x4 and only driven a few hundred miles a year.&nbsp; Seems one of the injectors had trash which jammed it open. It leaked a half cup or so of gas, and with both valves closed, it didn't evaporate.&nbsp; When we tried to start it, the incompressible fluid bent the rod, and the bearing failed.&nbsp; Interesting as hell, but it cost $2200 to fix.<br><br>If you get up near Conroe, let me know.&nbsp; I'll listen to it myself&nbsp; <img class="emoticon bbc_img" src="/images/boards/smilies/smile.gif"><br><br>Bama<br><br>

 

[James AKA Lynx]

Thanks, Good news. I hope to solve it this week and next week take off for a couple of days in the middle of the week. Probably up your way. Maybe we can meet. I will PM you before I leave.<br><br>James AKA Lynx

 

[wrcsixeight]

You do not want carb cleaner in the motor oil for long.<br><br>Lots of things can sound like ticking lifters with the same general frequency.<br><br>Exhaust manifold leaks or the fuel injectors themselves.<br><br>What weight oil are you using? &nbsp;Sometimes too thick an oil starves the lifter. &nbsp;There is a tendency for people to put really thick oil in an engine thinking it protects better, or if it is to be super hot, like in texas in summertime. &nbsp;If the cooling system is in good condition, stick with the 5w/10w-30. &nbsp;Thicker oil can only protect better when the oil temperature gets super super hot, and the engine is under load, the rest of the time the thicker oil causes less oil to flow to through the lifters to the top of the engine to cool it, and more friction and pumping losses.<br><br>Lots of people claim to fix ticky lifters with MarvelMysteryOil. &nbsp;The MMO is very thin, and perhaps just the thinning out of the motor oil is a significant contributor to the reported positive results

 

[James AKA Lynx]

I can understand about the carb cleaner in the lifters. What I was going to do is spray the lifters through the rods. Waite a while, unplug the coil wire, turn the enging over 1x and spray again. The next morning, spray again. Then change the oil.<br><br>I have 10W30W now. I did add some STP additive and it quieted down some. Not all the way. I should have drained a quart out first. The oil has been changed. It does look blacker than fresh with less than 25 miles on it.<br><br>I have read one reference about the fuel injectors being cloged. My engine idles smooth.&nbsp; I thought the only filter was in the tank. suggestions on cleaning the Injectors? Sea Foam?<br><br>James AKA Lynx

 

[wrcsixeight]

STP is an oil thickener. &nbsp;No real detergents or anti wear additives, just dilutes the additives in the motor oil really. Like most motor oil additives, avoid.<br><br>You said you have been running lots of fuel treatments. &nbsp;I've read how overdosing on fuel additives can actually cause injector issues if it dislodges a chunk of varnish in the fuel line. &nbsp;My injectors have little screens that have collected debris, despite a sock filter on the pump in the tank, and a regular filter inline. I only have 2, in the throttle body, you have one for each cylinder.<br><br>Seafoam is 60% IPA alcohol, some pale oil and some Naptha bring it to 95%. I am not adding any more alcohol to my gasahol.<br><br>Techron was the original PEA based fuel system cleaner, which cleans and dissolves carbon without leaving any residue of its own.<br><br>Gumout Regane, Redline SL-1, CRC GTP, &nbsp;and some others all have good amounts of PEA. &nbsp;It adds a distinct fishy smell to the product.&nbsp;