engine tapping ...oh no

[IndianaVX]

ok,
my engine runs like a sewing machine...smoothe.....until tonight.
i drove to town, and picked up my brother, and while sitting in the driveway, i heard a faint, rapid tapping, and it seemed to be comming from the drivers side, back by the firewall. i reved it just a tad, and the tapping went away. so we went down the road just a bit, got some drinks, and while sitting there,(he went in), i checked my oil, which was just a hair low, but no tapping, so i grabbed the cable and reved it a bit, and the tapping returned, but just briefly, reved it again, and it didnt increase or get louder, it just quit, and i havent heard it since...
what should i be checking, help me, i am scared to death. its not loud, it almost sounded like when we were kids, we would put cards in the spokes of our bikes to make em sound cool. well, it kinda sounded like that except more metallic.
it sounds like a valve tapping, but only for a few seconds, not constantly.
YOUR HELP PLEEZE!!!

Thanks
david

[Joe_Black]

Is it a sort of ball-bearing-on-plate type of tapping? Or ball-pien-hammer-on-steel-bar tapping? What kind of oil are you using (brand, synth or dino, grade) and what's your local weather during this tapping?

[IndianaVX]

thanks joe for taking intrest...........
i would say, ball bearing on plate, or glass, rapid tapping, for just a few seconds, like ten or so, then i reved, and it went away. when the rev idled down, it was gone. it was evident enough that my brother, who knows nothing about engines, said "that sounded weird, you still have a warranty?" gulp......
using Mobil 1 10-30.....weather is warming up...it was about 60.

[Y33TREKker]

Are you sure it was a mechanical tapping and not an electrical snapping? Maybe something in the ignition?

[IndianaVX]

:_confused well, does the coil pack make any tapping noise??? i mean im pretty durn sure it was mechanical, but ive never dealt with these coils over plug setups..... i suppose it could be a rapid snap snap snap snap noise. also, when i started it up this morning, i heard the slightest of rattleing of sheet metal. dont think its related, but i dont know. havent been home again since this morning to check it out.....
thanks guys, ill keep answering if you keep asking....

thanks again,
david

[Tobert]

It could be valve adjustment. Mine taps like crazy, especially on lighter weight oils.

[Y33TREKker]

It could be valve adjustment. Mine taps like crazy, especially on lighter weight oils.

I was just throwing out ideas with the electrical snapping idea. I guess I had just assumed that the 3.5L VX motor used hydraulic lifters, but I see from the cd manual that a solid lifter bucket/shim type adjustment is used, so valve adjustment could very well be the cause.

How many miles on the engine? VX valve adjustment intervals are every 60k miles.

[IndianaVX]

just rolled 63000..........

[Ldub]

Check your exhaust system to find the most likely cause of the sheet metal rattling sound...the heat shield(s) are a known culprit.

[Joe_Black]

If you have a Harbor Freight nearby you can pick up a mechanic's stethoscope for about $6 which can help isolate the source of the sound. You can also find them at NAPA and other auto parts houses for a little more.

If the sound is coming from the head then it's likely the hydraulic valve-lash adjusters, which have a published known-issue of sticking from varnish build-up. The typical "fix" is the use of 0W-30 or 5W-30 Mobil-1 which will remove the varnish over a period of time. The adjuster could also be failing (unlikely at your mileage, but possible), which in a worst-case scenario would cause very rough running as the affected valve stuck open.

Ldub's exhaust shield clatter is another valid possibility, and a while back Johnnyapollo had a noise that would only happen while in drive that turned out to be the exhaust making contact with the right side suspension link.

How long have you had your VX and been using Mobil-1?

[psychos2]

If the sound is coming from the head then it's likely the hydraulic valve-lash adjusters, which have a published known-issue of sticking from varnish build-up.

What??? The only way to adjust the valve is with a type of shim that goes on top of the valve stem. We call them lash caps at work. We do not have lifters on the vx. It is a setup were the cam opens the valves. shawn

[Joe_Black]

I know, that's what I thought at first since that's what I'm familiar with as well from my FIAT/Lancia and Kawasaki DOHC experience. Apparently, and this is according to Isuzu service information and not my actual under-hood experience, our engine has hydraulic self-adjusting "lash caps". I'm about to have lunch with a friend who owns and operates a local major repair shop and will have more info then.

UPDATE: Apparently there is a such thing as a self-adjusting hydraulic tappet bucket for direct-impinging OHC and DOHC applications. When home later I'll look in the service manual for more info.

http://159.51.238.62/remotemedien/media/_shared_media/products/automotive/engine/valve_lash_adjustment_elements/hydraulic/138232_aaa_rgb_COL_2.jpg

[IndianaVX]

thanks guys
yes, i am suspicious of the exhaust rattle, not real concerned about it, but it will be found and dealt with....
Joe, i have owned the vx for a year, and changed to mobil 1 2 days after i got it. so its been running mobil 1 for a year. i also run the lucas syn oil stabilizer. and run the lucas gas additive...(forget the name) for cleaning the top end.
there is no noticable power loss, i cant make the tapping. it just happens. have heard it once today.
thanks again guys for the intrest, and input.....its appreciated
lunch is over... gotta get back at it!
david

[IndianaVX]

ok, i think i got AUDIO, and a pretty lousy video, but it is the sound im after....take a listen. its not the best sound quality, and it is loud because i stuck the camera right down in there. camera location is just above the spark plug closest to firewall, on drivers side. i used my stethescope, and it is defenatly loudest there also. i put the scope in the indented groove on the "valve cover?" just above the spark plug. i also stuck it in the indent around the spark plug. both places it was very distinct tapping.
so, if this works, heres my audio clips.......

ok, thats not working....posting the video, that is.....ill try something else

[IndianaVX]

ok, heres the link to some videos with audio of noise.....

http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1848.flv


http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1849.flv

the first one is with engine still running after a 5 minute drive.... the second one is after shutting the engine off for about 2 minutes, and i rev, and the sound goes away.

thanks guys
david

[psychos2]

I know, that's what I thought at first since that's what I'm familiar with as well from my FIAT/Lancia and Kawasaki DOHC experience. Apparently, and this is according to Isuzu service information and not my actual under-hood experience, our engine has hydraulic self-adjusting "lash caps". I'm about to have lunch with a friend who owns and operates a local major repair shop and will have more info then.

UPDATE: Apparently there is a such thing as a self-adjusting hydraulic tappet bucket for direct-impinging OHC and DOHC applications. When home later I'll look in the service manual for more info.

http://159.51.238.62/remotemedien/media/_shared_media/products/automotive/engine/valve_lash_adjustment_elements/hydraulic/138232_aaa_rgb_COL_2.jpg


I have looked in the manual and I am finding nothing about this. It looks to me that this is not the case and they are not self adjusting. But I am not 100% positive. If they were self adjusting hydralic there would be no valve noise. You can notice a big difference between hydraulic and and solid lifters, I would think that this would be the same. shawn

[psychos2]

ok, heres the link to some videos with audio of noise.....

http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1848.flv


http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1849.flv

the first one is with engine still running after a 5 minute drive.... the second one is after shutting the engine off for about 2 minutes, and i rev, and the sound goes away.

thanks guys
david


It sounds like you may need the valves adjusted. It says in the manual they should be checked every 60,000 miles. shawn

[Joe_Black]

After taking a look at our shop manual I have to concur with psychos2 that we do not have the hydraulic type lash adjusters, as they look like good ol' bucket tappets:
http://www.vehicross.info/forums/attachment.php?attachmentid=523&stc=1

Now I'm all curious where this "hydraulic valve lash" info came from referencing the 6VD1 and 6VE1 engine. :confused: Oh well, another challenge.

My apologies if I led anyone astray! ;)

[VehiX]

ok, heres the link to some videos with audio of noise.....

http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1848.flv


http://s169.photobucket.com/albums/u213/IndianaVX/?action=view&current=100_1849.flv

the first one is with engine still running after a 5 minute drive.... the second one is after shutting the engine off for about 2 minutes, and i rev, and the sound goes away.

thanks guys
david

That doesn't sound good at all! Sounds like an old mercedes deisel.

[Tobert]

Mine sounds just like that and has ever since I got it. I've put almost 10k on it and no problems yet. It is rather annoying though.

[Cyrk]

Mine was sounding like that... I could not totally tell with my S/C and exhaust... but brought to my Mechanic, and he did a valve adjustment on it.

I have around 55K miles on mine.

[IndianaVX]

yeah, im thinking it sounds like a 3.5 desil... ive decided to do the seafoam treatment. got 3 miles on it so far. will do an oil change in 497 miles, if its still tapping, its going in for valve adjustment, ugh. hoping the seafoam will clean it out though, which im sure it will, but not sure it will stop tapping. could have probably used the cleaning anyway.
keep the replys comming though. it sounds like theres alot of valves needing adjusted.......lol.
thanks peeps,
david

[IndianaVX]

UPDATE
ok, im gonna change the oil, with the seafoam in it, on saturday, that will put it at a little over 400 miles with it in there. the tapping hasnt gone away...hasnt gotten worse either, but i will tell you something thats come back........MY MILEAGE!!!! more on that in a minute
QUESTION i got the stethescope out again today, and was listening, and i may have found my tapping. there is a square box, on the same mounting as the fuel pressure regulator. seems to be a valve or solenoid of some sort, maybe a purge valve or solenoid, and there seems to be a piston in there somewhere, cause its tapping like theres no tommorow. anybody know what im talking about, had this problem, or has anyone replaced this part, and why?? i looked thru tones manuel, and you can see the part im talking about in the picture of the fuel pressure regulator, but it doesnt identify it.
HELP NEEDED

ok, now for the better news. after a can of seafoam in this tank of gas, wiffing half can thru the pcv, and having half a can in the oil, mobil 1 with lucas syn oil stabilizer,
and a whole week of little 8 mile trips, all in town driving, zippin all over the place, i got 297 miles befor the light came on, and even it shut off when i came into the driveway tonight. for me that is excellent. in theroy, i should have around 320 or so miles if im doing highway miles in there too, maybe. but this is great news for me. the short trips have been killing my mileage lately.
so, im asking again for help from you guys on the identifying of the part described, and any opinions on if this makes sense on my tapping issue.
thanks in advance
waiting patiencly for a response
david

[psychos2]

Is it the egr valve? There is a nut on the bottom that can come loose and rattle. shawn

[IndianaVX]

no, its not the egr........its on the back side of the engine, by the firewall, on the drivers side. just above the back coil pack, on the drivers side.theres a bracket, that holds the fuel pressure regulator, theres a hose with a light blue,(i think) cap on it, and nestled in this bracket is a silverish box, and the tapping is REALLY loud when i listen there with the steth. dont know what it is, but it sure is making alot of racket. dont know what to ask for to replace it, or even look it up on the board..........hmmmmm

david

[Ldub]

That silverish box with the blue cap...sounds like you're describing one of the ports in the A/C system.

[IndianaVX]

Ldub,
well, now that its light, i can describe better.
there is a EVAP cap just below this box im describing, but it doesnt connect to the box im describing. just above this cap is a silver bracket that mounts to this box thats making all this noise. in the silver bracket is 1 inch cylinder that also has a orange plug behind it. then immediatly behind this plug, moving towards the middle of the engine is this black box, maybe 2 inches square, and its tap tap tapping loudly.
Just changed my oil, and the engine is running smooth, and yeah, i can hear a very small valve tapping, but using the stethescope, i cant really hear the valves when i listen around the covers and other places, but i hear this box tapping everywhere on the engine, just not as loudly. i hope this makes sense.
thanks guys for the looks and help.....im still needing it.

[Ldub]

OK, now ya gone went n done it...ya stumped the guesser !

I see by your gallery that you have photo technology, yer gonna have ta post a pic for me to have even a clue as to what you are talking about. :confused: ;)

[IndianaVX]

Ok, got some pictures, with homemade arrows even...... please, excuse how dirty my engine compartment is, been working at a place with a long gravel driveway.....but its warming up, and i promise you, i will have it all nice and clean again:p
back to the matter at hand.......the noisy black box

http://www.vehicross.info/gallery/data/500/thumbs/100_1851.JPG (http://www.vehicross.info/gallery/data/500/100_1851.JPG)this is the general location...drivers side, back, etc

http://www.vehicross.info/gallery/data/500/thumbs/100_1852.JPG (http://www.vehicross.info/gallery/data/500/100_1852.JPG)

http://www.vehicross.info/gallery/data/500/thumbs/100_1854.JPG (http://www.vehicross.info/gallery/data/500/100_1854.JPG)

http://www.vehicross.info/gallery/data/500/thumbs/100_1853.JPG (http://www.vehicross.info/gallery/data/500/100_1853.JPG)here you can see the black box, right behind the oxidised silver clip. what is this thing??? government tracking device that uses morse code? what ever it is, i am getting alot of tapping noise from it, and has anyone else had this thing do this??
have at it buddys, i dont have a clue. also, it doesnt seem to tap when the engine is cool, or cold, but after the engine warms up, the tapping is constant, and kinda decreases with revs.
thanks guys, i really appreciate it!!!

david

[Ldub]

Near as I can tell...that would be your fuel pressure control valve.
Take a look in the shop manual that Scott recently made available for download & look under "fuel system".

[IndianaVX]

well,
not for sure, but maybe, the sound you hear in my earlier post may be the sound of a timing belt, or tensioner going out. my belt jumped, and now the truck is in the shop.
just an update. any body having some ticking in their engine should maybe investigate. i only have 64000 miles on the vx. belt is said to be replaced at 100000.
just letting you know whats up with an update.
thanks for your help.
still dont know what the black box is though

david

[Y33TREKker]

I was just looking through a '99 VX Electrical Troubleshooting Manual and saw a picture of that general location. Any chance that's the Intake Air Vacuum Switching Valve making all that noise?

[IndianaVX]

Hmmmm,
with a name like that, im sure it COULD make some noise!!! i dont have that manual so im not sure, but it sounds like it could be something like that. it DEFANTLY has a valve, or piston moving in that "black box"
thanks for the post, i will look into it when i get my truck back from the shop.

UPDATE ON TRUCK......
talked to the warranty people today, but not the jerk ive been talking to.
this guy was as cool as could be. told me to have the mechanic look into bent valves and what not. HE was pretty sure it was an interferance engine (i know, i know) and that i should have it checked out anyway, and the cost of the diagnostics would be absorbed in the R and R with the timing belt!!! (why cant all agents be like this guy??)
he also was saying that i should replace the water pump, cause it will go bad, or may have caused the timing belt jump in the first place. the other agent just wanted to replace the belt, and send me down the road. So anyway, I miss my truck.
hopefully, i will have it back on the road soon.
thanks for all the info, and posts!!

David

[CowboyErik]

Hey! I listened to your video; and your VX sounds just like mine started to sound a few weeks ago! My timing belt tensioner had totally failed! The tensioner cylinder is hydralicaly loaded and provided pressure to the belt; I put a new one in 11 months ago when I did a timing belt job; and the NEW tensioner failed completely! I'm amazed the timing belt didn't jump! Terrible sounds, I thought all the things listed in this post, EGR or intake manifold clogged, PCV valve clogged, valves going out of adjustment, but the clue in your post is that you were convinced the sound came from your drivers side camshaft; well, that is the one that would make the loudest noise because it's out of sync with the other came, and it sounded TERRIBLE! Replaced the waterpump again! NEVER BUY AUTOZONE WATERPUMPS FOR VEHICROSS!

[SilverBullet75]

Hey! I listened to your video; and your VX sounds just like mine started to sound a few weeks ago! My timing belt tensioner had totally failed! The tensioner cylinder is hydralicaly loaded and provided pressure to the belt; I put a new one in 11 months ago when I did a timing belt job; and the NEW tensioner failed completely! I'm amazed the timing belt didn't jump! Terrible sounds, I thought all the things listed in this post, EGR or intake manifold clogged, PCV valve clogged, valves going out of adjustment, but the clue in your post is that you were convinced the sound came from your drivers side camshaft; well, that is the one that would make the loudest noise because it's out of sync with the other came, and it sounded TERRIBLE! Replaced the waterpump again! NEVER BUY AUTOZONE WATERPUMPS FOR VEHICROSS!

Hi, my VX just started sounding like this too. In fact your situation with the timing belt sounds identical to mine. I replaced mine about a year ago. My question... What is causing the noise? The engine is still running good, so I don't think the belt has slipped. (I'm just praying it's not a spun bearing, or rod knock).

[SilverBullet75]

A HUGE THANK YOU TO COWBOYERIK!!!!!!!!!!

I've been in a VX depression ever since I heard that darned knocking sound in the motor. I even warned my wife about the "potential" of the motor going kaput long ago. After reading CowboyErik's post, I felt I had hope still. Sure enough! I pulled off the passenger side timing belt cover enough to push on the belt. Without any trouble at all I was able to deflect it by almost an INCH! So, after about 45 minutes I had the front end torn apart and found that the timing belt tensioner went bad!!! I can plunge the piston with my hands with ease, and there is oil leakage around the "pushrod" base. (see pics).
SO, IF YOU THINK YOU HAVE ROD KNOCK/ENGINE FAILURE, CHECK THIS BEFORE SENTENCING YOUR VX MOTOR TO DEATH!!!!http://www.vehicross.info/gallery/data/500/tensioner1.jpg
http://www.vehicross.info/gallery/data/500/tensioner2.jpg

[Chopper]

Nice catch!!

[CowboyErik]

Amazing isn't it! I thought my VX was dying to! Going to Indy500 this year? People really think VX is badass at the track!

[Gussie2000]

Mine sounds just like that and has ever since I got it. I've put almost 10k on it and no problems yet. It is rather annoying though.

I bought mines with that tapping too.Now it taps harder when it's cold,but after 5+ minutes the taps breaks down quit away.

I was concern about that,so i had an isuzu specialist checked it,he said that tapping happens because the VX were sit for a long,long period of time,my VX were storaded for almost 5 years in massachusset before the son of the previous owner's (who died) decided to get rid of it,that's why my VX only had 38K on the clock when purchased on november last year,he also said that will not cause any damage to the engine,neither the engine's performance. I've add almost 5,000 miles since & truefully the VX runs very smooth,it starts rightaway & never give me any troubles so far.

My mech told me to use 5w 20 mobil,but i didn't supposed to add lucas oil stabilizer,however i'll have the VX into the shop as soon fall season shows up to correct that little annoying noise.The tapping is right under the left cover or passenger side.

[CowboyErik]

I finnally ran out of brake pad on my VX. When I did, I figured I would replace rotors and pads; I also wanted to strip and paint my calipers, they have a rusty surface. I got the car up in the air and ROTORS don't come off like anything I've ever worked on! Looks like you have to pull the hub? How difficult is this? Is this when people do bearing repacks also? I might just paint my calipers and puts the pads on; any advice is appreciated! So far my 2nd timing belt tensioner is holding, I checked it over the winter! Thanks! Erik

[Gussie2000]

I finnally ran out of brake pad on my VX. When I did, I figured I would replace rotors and pads; I also wanted to strip and paint my calipers, they have a rusty surface. I got the car up in the air and ROTORS don't come off like anything I've ever worked on! Looks like you have to pull the hub? How difficult is this? Is this when people do bearing repacks also? I might just paint my calipers and puts the pads on; any advice is appreciated! So far my 2nd timing belt tensioner is holding, I checked it over the winter! Thanks! Erik

I quit sure many of the members had they caliper replaced at the own house so just check all related threads & you can figured how to do the job.

I replace my OEM rotors with R1 concepts drilled/slotted rotors & satisfied brake pads which i love how they performed together,excelent braking.