Help - what's that ticking sound?!

[thechoochlyman]

I just pulled a B4V home over the weekend and this tick seemed to have popped-up during the trip. I just got done pulling several hills, topping out at 208F and holding about 1000-1200 (pre-turbo) EGTs for a couple of minutes at a time. We stopped for lunch before descending the other side of the mountain and I noticed the tick when I fired it back up.

There was nothing unusual on the rest of the way home. I've driven to work two days since then and it hasn't changed as far as I can tell. It stays in-sync with engine RPM at any speed. There is no change in how the engine runs and it's still smooth as ever. I can only barely hear it from inside the car. I used a stethoscope to do some poking around, but couldn't really narrow it down other than it seems to be coming from the back side of the engine. I dosed it heavy with injector cleaner and changed the fuel filter with no affect. I broke all the injector lines loose while it was running and it didn't go away, so it doesn't seem to be an injector.

My theory is that I got the exhaust manifold hot enough to blow out part of the gasket or crack the manifold. Haven't had the ability to really inspect it yet, but I do know that an exhaust can sound an awful lot like lifter tick. I have 5,000 miles before my timing belt is due and would really prefer to wait until then before I take off the valve cover for further inspection. But if it seems to get worse before then, of course I'll tear it down early.

video.

 

[akal65]

I just pulled a B4V home over the weekend and this tick seemed to have popped-up during the trip. I just got done pulling several hills, topping out at 208F and holding about 1000-1200 (pre-turbo) EGTs for a couple of minutes at a time. We stopped for lunch before descending the other side of the mountain and I noticed the tick when I fired it back up.

There was nothing unusual on the rest of the way home. I've driven to work two days since then and it hasn't changed as far as I can tell. It stays in-sync with engine RPM at any speed. There is no change in how the engine runs and it's still smooth as ever. I can only barely hear it from inside the car. I used a stethoscope to do some poking around, but couldn't really narrow it down other than it seems to be coming from the back side of the engine. I dosed it heavy with injector cleaner and changed the fuel filter with no affect. I broke all the injector lines loose while it was running and it didn't go away, so it doesn't seem to be an injector.

My theory is that I got the exhaust manifold hot enough to blow out part of the gasket or crack the manifold. Haven't had the ability to really inspect it yet, but I do know that an exhaust can sound an awful lot like lifter tick. I have 5,000 miles before my timing belt is due and would really prefer to wait until then before I take off the valve cover for further inspection. But if it seems to get worse before then, of course I'll tear it down early.

video.

it could be the N75 valve.

 

[jaysen71581]

check your tensioner pulley, when that back piece goes bad it will tick.

 

[thechoochlyman]

it could be the N75 valve.

Just tried starting the engine and unplugging it, no dice.

check your tensioner pulley, when that back piece goes bad it will tick.

No issues there either. Pulley is spinning nicely and not bouncing.

I just gave another go with the stethoscope. Might be originating behind the intake manifold, but hard to tell.

 

[Windex]

Sounds very much like a lifter.

I would use a stethoscope with a rod to touch the part being listened to, as well as just a hose. Hose is good for exhaust leaks. Touch-rod is good for lifters or other mechanical noises.

 

[thechoochlyman]

Although I didn't want to, I went ahead and pulled the valve cover. (hopefully it won't leak too bad until the next TB!)

I tapped all the non-compressed lifters with a copper rod and a mallet, then rotated the engine and did it again. All seemed nice and "sproingy." I took a few photos so you can see how they look. Couldn't see any visible wear or damage to any of the lifters, there were a couple of places on a cam lobe or two that I circled. Nothing too bad though. I didn't see any indication that any lobes had been worn down past the hardened surface.



This one might have some flaking started on it. (below)








I'll also add, I briefly started it for a few seconds with the valve cover removed and it didn't seem any louder than before. I guess it's worth cleaning up the oil splatter.

 

[thechoochlyman]

As soon as the county crew are done with their noisy machines outside I'll go back out and see if there is any noticeable difference with the clutch pushed in.

What's everyone best company for oil analysis? Might send one off just to rule out possible main bearing failure.

 

[Windex]

I've seen worse (cam lobes) not ticking.

If you are at the point where you have the cam cover off, get each lifter on the base circle of the cam and try to depress it by hand with a chopstick.

if you have one that is collapsing, it will compress easily and feel spongy - the rest will feel solid.

 

[thechoochlyman]

I've seen worse (cam lobes) not ticking.

If you are at the point where you have the cam cover off, get each lifter on the base circle of the cam and try to depress it by hand with a chopstick.

if you have one that is collapsing, it will compress easily and feel spongy - the rest will feel solid.

I already put the cover back on, but I did put enough pressure on the lifters that I'm convinced the issue is not there. They were all extremely tight when I tapped on them. I do not think I could have pushed one down with hand pressure alone.

 

[thechoochlyman]

I've been searching for clearance specs between the camshaft and lifters but I'm not having any luck.

EDIT: This post has what I needed. .1mm or less clearance. I might pull the cover again tonight to check clearances.

 

[ToddA1]

I had a gas rabbit that sounded like that. Ended up being a worn valve guide.

-Todd

 

[thechoochlyman]

I had a gas rabbit that sounded like that. Ended up being a worn valve guide.

-Todd

Wouldn't be ideal, but still not the worst thing I suppose.

 

[thechoochlyman]

I took the valve cover back off. A . 004" feeler gauge would not go between any of the lifters and cam with the lobes pointing straight up. And all the lifters would spin freely.

 

[ToddA1]

Well, you asked for opinions, I just gave a personal experience. Hopefully, it’s not your issue, but I wouldn’t be surprised if those hills caused that tick or at least exacerbated it.

-Todd

 

[thechoochlyman]

...I wouldn’t be surprised if those hills caused that tick or at least exacerbated it.

-Todd

Unfortunately I'd say you're right. Even though I didn't push the EGTs very hard it's entirely possible that it was just too much for an engine with 300k miles on it already.

Well now I'm in a bit of a quandary. I'm pretty confident that this is a top-end problem, because I feel like main bearings wouldn't sound so regular at any load or RPM range. And the ticking noise does seem to be at half the rate of the engine RPM, so valves/lifters are still likely.

Having a B5 I just finished an engine swap in means I can have the B4 down for a few weeks if necessary. If I needed to keep driving it right away I'd swap in the engine I just picked up and tear my old one down when I find the time. I think I need to remove the head just to see what's going on, unless I get the camshaft off and find some obvious issue with the lifters first. If I do find head damage, I can send it off to Frank. Hopefully there weren't be any signs of piston contact, but I don't see why that would have happened.

 

[thechoochlyman]

After reading a few other threads I settled on going forward with just a cam and lifter replacement to see how it goes. If I do end up pulling the head later I'll want to replace the cam anyway, so no harm in just trying the cam first to see if it helps.

 

[Phi1osopher]

This (eBay LINK) is the Cam and lifter kit I bought. OEM and about $180 shipped with Tax. It probably could be replaced in a few hours, maybe faster if you used clamps on the timing belt to make sure it doesn't slip while doing the job. I had similar ticking and clicking to yours, and replacing this made the noise go away and the car run smoother with noticeably more power. Of course part of the power increase can also be attributed to my worn timing belt and having the timing corrected.

Also, those cam lobes visibly look a bit rounded/ worn to me. I forgot to write down the lobe height when I measured them, but on my old one each lobe was slightly different, +/- 0.3mm, which really is quite a bit. It probably doesn't have a huge effect on the way your engine is running, but it likely is having at least some negative effect.

 

[thechoochlyman]

This (eBay LINK) is the Cam and lifter kit I bought. OEM and about $180 shipped with Tax. It probably could be replaced in a few hours, maybe faster if you used clamps on the timing belt to make sure it doesn't slip while doing the job. I had similar ticking and clicking to yours, and replacing this made the noise go away and the car run smoother with noticeably more power. Of course part of the power increase can also be attributed to my worn timing belt and having the timing corrected.

Thanks, Phi1osopher! I ended up purchasing the kit on IDParts yesterday with two-day shipping so it'll be here for the weekend. I only have 5,000 miles left on my current timing belt, but I'm going to hold off on that until I find out if the cam and lifters does the trick... just in case it's still there and I need to pull the head.

Since I'm now not hijacking the other thread, did you see any evidence of damage to your cam or lifters? Any signs of the lifters leaking down? Seems like it's a rather difficult thing to accurately "test" your lifters aside from flat-out replacing them.

 

[Phi1osopher]

I honestly did not do a lot of diagnostic inspection before making the decision to buy my cam and lifters. There were several factors: I have been a mechanic a long time and it just seemed likely to be the problem, I am in a moment in my life where I had some extra $$, I was about to do a timing belt anyway, AND I knew my engine has a lot of miles on it. So I just bought it before even removing the valve cover, figuring if my old cam looked perfect I could probably return it...

When I opened the valve cover everything initially looked pretty good with no scoring, etc. However measuring the lobe tips revealed a discrepancy across them of around 0.05mm; I was happy to just plop the parts in while things were apart. You don't need to hear this, but future readers of this post should remember to use some assembly lube oil on the cam, lifters, and cam journals while assembling the new parts.

Also, if you are not replacing the timing belt, I would of course still lock the injection pump and try to lock the crankshaft at TDC, plus have the correct cam locking tool handy (for reassembly). I would also use 3 to 6 of THESE CLAMPS (or something similar) on the timing belt to try to hold it snug on all the pullies while the cam sprocket is off, hopefully to prevent any belt slippage...

 

[thechoochlyman]

Good idea, I do have some of those spring clamps laying around somewhere.

 

[thechoochlyman]

I've got my old camshaft out and I'm just waiting for the new one to show up via UPS today. Rather disappointingly (in my case), there was no obvious signs of wear on either the cam or the lifters. The cam lobes all measured between 1.830-1.8325, and all the lifters measured 1.3765 across the entire body.

 

[thechoochlyman]

Just got the new parts in and did some measuring. The new cam measures 1.850 across the intake lobes, in addition to being much more obviously rounded on the ends. Have to say I'm feeling pretty positive about it, but we'll see.

 

[thechoochlyman]

I completed the installation without a hitch, but now I have a very odd no-start issue. Possibly fuel pump out of time?

I rotated the engine to TDC, locked the pump, and put my plate across the cam. Loosened the TB tensioner and knocked the cam gear off. Swapped the cam, finger tightened the cam gear bolt, tensioned the TB roller, torqued the cam gear, and released everything. (I did clamp the TB to the pump gear as philosopher suggested, and I'm certain it didn't slip a tooth anywhere.)

I cranked and cranked and it wanted to fire a couple times here and there. Topped off the fuel tank. Changed the 109 relay. Jumped the fuel shutoff solenoid to the battery. Held the pedal to the floor while I cranked. It will fire on starting fluid and try to run for a few seconds, but eventually sputter and die. Seems to be getting fuel from all the white smoke.

 

[ToddA1]

Held the pedal to the floor while I cranked. It will fire on starting fluid and try to run for a few seconds

I’m not sure throttle input has any relevance on a TDI, when starting. ECU is under control.

Ummmm…. starting fluid? Advance the cam 1 tooth clockwise, to see what happens.

Pretty interesting cam profile difference. The new cam will have more duration. I can’t imagine that much metal wore away from your original cam. I know people swap cams, but I’m wondering what mileage is usually the determining factor.

-Todd

 

[Windex]

Lifters need to fill with oil.

Remove the glowplugs, disconnect the main harness at the pump, and crank the engine over several times to fill the lifters.

Alternatively leave the GPs in and take a 2 minute pause after cranking 15 seconds until the car starts

Once the car starts the remaining lifters will tick until full. Hold revs at about 1500 until the last lifter goes quiet

 

[burpod]

going to have to recheck cam/crank/IP with the lock tools again...

 

[thechoochlyman]

I’m not sure throttle input has any relevance on a TDI, when starting. ECU is under control.

Yeah, that was more for the sake of trying to keep it running it if *did* try to fire.

Ummmm…. starting fluid? Advance the cam 1 tooth clockwise, to see what happens.

If the cam is lined up with the engine at pump at TDC, what would be the benefit of advancing it one tooth?

Lifters need to fill with oil.

Remove the glowplugs, disconnect the main harness at the pump, and crank the engine over several times to fill the lifters.

Alternatively leave the GPs in and take a 2 minute pause after cranking 15 seconds until the car starts

Once the car starts the remaining lifters will tick until full. Hold revs at about 1500 until the last lifter goes quiet

No worries there - it's been cranked plenty enough to fill the lifters at this point.

going to have to recheck cam/crank/IP with the lock tools again...

Yep, gonna be on it.

This is kind of a crapshoot, but I know my timing was already advanced at the top of the graph previously. Could re-torquing an old belt that's already kinda stretched advance the timing even further? I might try retarding the timing at the pump just to see what happens. With how little it's trying to burn it really feels like fuel is being injected way too late in the stroke.

 

[thechoochlyman]

Good news and bad news. I rechecked the timing, the IP was off by one tooth. After that it fired right up without fuss. The bad news is that the tick is still here. At least I can tell the engine actually runs better with a little more power for whenever I get this whole thing straightened out. lol

I guess pulling the head is next. At least I know I have a good spare engine to play with if I really need it.

 

[thechoochlyman]

Here's a photo of something I found interesting. I wouldn't expect this kind of porosity in a head, but I guess it doesn't hurt much.

 

[burpod]

i've seen that before, but not quite as much. from what i understand, most of the load is on the top part of the bearing, if that's correct, i would guess those wouldn't cause much harm?