So - just some background on my car - This is my 2nd engine as I lost my first to oil loss (lack of monitoring due to a troubling time in my life). This occured in 2020, around 4 years ago.
While the replacement was out I had the shop replace my timing chain tensioners and guide rails as well as all 8 plugs at 54k engine miles, and swap over my newer accessories like mounts/water pump.
Chain Tensioner: AJ813898 Chain Guide: C2Z28431. I received my old parts back and the wear wasn't really bad at all, they said during the teardown it looked pretty good for a salvaged engine.

In December, I had my shop do the valve covers both banks to address an oil seepage/evap issue I've had. Not cheap, but thought I was making the engine more robust for it's remaining useful life.
When replacing all the parts/SC, I ran into 3 injectors stuck open which the shop then had to pull out and replace. I also had them throw on a new VelocityAP drive belt while they were in there as there was some minor cracking on the original ribbing.

In April, I noticed a weird ticking noise, which I couldn't isolate to the front of the engine. I decided to bring it back, and the shop thought this was related to the belt tensioner systems which they replaced in full (drive tensioners/belt, FEAD system tensioners/belts). This seemed to check out as after return the noise disappated. I noticed that it came back on time since then, but I couldn't replicate it after that so I chalked it up to a coincidence. The rest of April went by until yesterday May 4th - I noticed the noise was back after a cold start.

I have the VAP crank pulley system installed and I am noticing some possible movement on the drive belt still, that may be related to this noise. I will investigate this further to see if I can isolate the drive belt system from engine idle.

It is really weird - attached is my video. I am skeptical to think that this is timing related, the engine runs really well and I have no codes. My oil analysis from Blackstone came back normal again, iron wear was higher than universal average but was like 30 ppm which has been consistent with my last 5 oil reports for the engine.

When I put a stethescope to the system, I have a hard time hearing a similar high pitched rhythm anywhere. I do hear something very similar when I scope the EVAP breather hose in the front of the engine and the black hose that runs just in front of the coolant expansion tank. Which makes me also confused. See attached photos.

 

Good troubleshooting and very thorough too! Gotta LOVE those Aluminum front cooling pipes too!
One thing to check?
We have seen one lower pulley separate from VAP. Is there any wobbling in the lower pulley? The one we saw was not too obvious.

This should be easy to check as you can remove the SC belt and run the car with no problems and you will quickly hear if the sound has changed.
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It's very odd this one. I will ask the shop to remove the belt to isolate the noise - I believe they did last time which is why they suggested the tensioner refresh. I have the solid silver crank pulley, installed around 2019 if I remember correctly. Double sided belt construction so i did not have the idler pulley VAP used to ship with the green 1 sided belt.

I see the belt traveling front to back a little, I wonder if one of them is just a little misaligned after the initial replacement as that seems the simplest solution.

In the video I also show a little bit of vapor near the back of the engine. That's what prompted this, I was on my way to take a longer drive to see a friend on Saturday, and a little puff of smoke emenated near the windshield. I was 5 minutes from home so I pulled over and went home to record this video. I really hope it's not the rear crossover. I replaced it as preventative maintenance in January 2022 while doing my supercharger oil change. If I need to do this again i might as well get my charger ported/polished in parallel.

 

Does that smoke smell like burning oil or sweet coolant? The valve cover gaskets are known to leak over time, so I wouldn't be surprised if it's small amounts of oil dripping on to the exhaust.

 

No, it didnt smell like much of anything, but my nose is bad so I knew I wouldn't be able to truly tell. I ventured a guess that it smelled mildly sweet like coolant.

The valve covers I had replaced in December, brand spanking new and updated a lot of inaccessible bits at the same time, so I am pretty confident that it is not oil. The shop agreed that popping the drive belt off again to have another listen would help us isolate this. I'm not great at earballing frequency of noise to see if this mimics crankshaft frequency but that seems reasonable. I'll be dropping it off on Thursday.

 

If it smells like coolant, it's time to get out the coolant system pressure tester. It's my #1 thing to harp on the interwebs. To check the health of the cooling system, you have to pressure test it because often the leaks only happen under pressure. Check the pressure rating on your coolant reservoir cap, and that is the pressure you need to pump up the system to do a complete test. The cap is the "fuse" in the system, so the rest of the system has to be able to survive that pressure amount or you have a problem(s) that need fixing.

But I don't know why people fight to the death before pressure testing their cooling system. Anytime any work is done that messes with the cooling system, it should be pressure tested. Most mechanics won't do that though and just wait for the customers to come back. And these cooling system testers are cheap on Amazon, or you can even borrow them for free at parts stores.

 

I certainly agree. But - you should know this was pressure tested in April while I was there at the shop. I saw the old stain from below my water pump and wasn't sure if I had a light leak. They put it under pressure for 20 minutes and there was no loss of pressure.
So, I could have developed a new leak, but I'll find out on Thursday/Friday of this week. I saw the vapor in the video on Saturday afternoon, and hadn't driven the car since Wednesday of that week. I venture a guess there might be some condensation but I didnt really have any temp swings or heavy rain that week either up here in Wisconsin.

The odd thing is I couldn't get this to replicate again today. I drove to the same spots, for the same time, to mimic my position on a hill should those variables impact it. I could not sniff coolant nor find a way to get the vapor to come back. It requires visual inspection as well with the cowl off to see if there is any staining back there too.

The ticking however, I was able to get quieted down (but still present) after driving at local speeds around town for 20 minutes. After a cold soak overnight, this morning I started up and the ticking present in the video was right back to the same loudness.

 

I agree this. Its the best and safest way to find the leak, even if the leak is for the cylinder or oil channel.
One tip to avoid problems with coolant systems: Never overfill the resevoir over max. Cooling system need that air space for heat expansion. (air compress, fluid don´t) If you overfill the resevoir there is less air to compress = Higher pressure in the system pushing all the seals. On race vehicles i allways used as big resevoir as i could find to have max air cap on resevoir. Never had to quit for a burst hose or water leak. (other reasons, yes)

 

That's the whole point of a pressure tester. It is to have a reliable and easily repeatable method to get up to max pressure to check for leaks. Driving around is not a reliable way to get to max pressure. The pressure is constantly fluctuating while driving.

You may not have a leak, or you may have a leak. Just get it pressure tested again to find out for sure. And make absolutely sure they are testing to the max pressure on the cap, otherwise, the test in invalid.

There was some other guy on here recently that was only testing to half the pressure of the cap, and fought me tooth and nail that he didn't need to test above 1/2 pressure to find a leak. He finally put up the pressure and the leak revealed itself immediate. Of course, he figured it all out on his own with no help from me, lol.

 

Thanks for the feedback. I certainly don't mean to sound contentious, I agree with you here. It is as simple as using the diagnostic to do the test and trace a leak. I posted on the forum to ask for advice on the sound, I know the next steps that I must take to root cause my leak, however ambient temp conditions and datalogged conditions do work well enough for collecting anecdotal evidence. The smoke happened well before engine reached operating temp, so I in no way shape or form believe it needs to reach max pressure to present itself again. I'm just noting the circumstantial information as I find it useful to present in this format.

I designed powertrain components and automated equipment for fluid fills for Fomoco, I have more IP in the industry than most on this forum. I just don't have a lot of time these days, so I don't do my own diagnostics as much anymore. I trust my shop and their technicians, they are not just wrench turners/parts replacers and I have a lot of OCD habits that don't help me troubleshoot my own car with eyes wide open. I don't often post for help other than for moments like these when others may have run into useful things that may help - I'm used to consulting for dealers and plant maintenance rather than the other way around. My point - I understand your post and am taking those next steps on Thursday, along with isolating possible bearing noise and drive belt system noise once again. I just don't hear any chain slap at startup, so my fears of a timing issue are precipitous at best.

 

UPDATE: No coolant loss, again under pressure. I was able to replicate the smoke again while picking up the car from the shop, and parking/idling on my driveway at home. I believe it's an oil smell, and I do not believe it's a leak. 4 days after driving it more, the oil smell has really dissipated and I've been driving it hard. My best guess is the oil was burning off from trace amounts trickled down from the valve cover replacement work. If it comes back, I know where to look and it's under warranty for 2 years.

Driving it hard probably sounds ill advised, but the shop was not able to replicate the sound again. I had it towed last Thursday, it cold soaked till Friday, and the tech called me to verify what I was thinking was going on.
They tried again over the weekend and then asked me if I wanted to pick it up Monday. Since then I've not been able to get it to come back after a week.

No noise is good noise, but this one was really odd. I'll keep my oil analysis going and probably leave it at that.

 

Another update - the noise came back after about a week. I stethoscoped it, felt like it might be coming from the front of the engine. I brought it back to the shop and didn't tell them what I thought - they also thought this is coming from behind the valve covers. They suggested next steps to teardown the front covers to identify what had happened. Through the oil hole I do not see much visible slack in the chain when I push or pull, but you can't check lower chain tension that way or the other bank.

I'm bringing it to another local shop who has done work on the car for a second opinion tomorrow, I have not driven the car much at all. Over the phone/email they thought this sounded really odd, like a weak lifter/tappet or something. They do a lot of Rover 5.0s and they felt confident they could confirm or deny what this was.

 

Thanks! I discovered my reservoir tank was 1/2 quart over filled. My low coolant warning came on although there was no leak. Now it's set at the max level when cold. The light comes on when the engine warms up. Probably a bad float.

 

The mystery continues. The noise came back for the 2nd shop. The master tech there has done countless timing chains, tensioners on the AJ133, mostly rovers. He personally owns two XJs (both 5.0s - one Ultimate was in the lot and it was his). To be honest I was surprised to see it, here in Milwaukee.

He didn't get any noise from stethoscoping the valve covers or the timing covers. He acknowledges the noise but does not think it's anything critical at all based on how the car performs.

He speculates possibly the previous shop may have left a leak on the exhaust manifold, since the sound goes down/away after running hot but was unable to confirm this that day. I have to bring it back on June 12th for him to do a larger teardown of the bay and further diagnosis.
Noise is gone again after picking it up, I'm driving it normally for now.

 

is the purge valve secured it's going at purge valve pace

oil smoke is valve covers yes they can warp. new ones are cheap

 

The purge valve appears to be secured and yeah I thought so too.
I either have two problems, or a mix of something. It's going back to the garage soon, today when starting up after a week and a half of trouble free driving daily, I had a random misfire and restricted performance.

Engine light went on and off during the drive home, idle improved and got P0303, cylinder 3 misfire, P0316 misfire detected on startup, and P02F0, cylinder 3 injector circuit range/performance issues. So, my money is on an issue with my injector, but I've seen 0316 come up for timing related issues as well. This all makes me very concerned.

 

Alright - the mission to have my car driven at any point during this nice summer we're having continues .
I believe I've isolated the smoke to a coolant leak. Under 20 PSI we did not notice anything. For some reason, it only was able to be replicated on a hilly parkway (my driveway for example) and I believe it is the upper heater hose, lower heater hose that goes to the firewall/heater core or both. It's going to the shop in a couple weeks for confirmation. I noticed some coolant stains on my passenger side CV boot and looking above that there was a little coolant on the top connector that connects the rear water manifold to the heater core hose. It's original to the 2012 mfg date so I figure it's time for some fun.

I replaced my cylinder 3 injector, so this makes 4 new injectors, 4 remanned injectors. (Cylinder 2, 4, 6 on drivers side, and cylinder 3 passenger side all new OEM).
After replacement of cylinder 3 injector, I started getting a P0031 for O2 sensor bank 1 sensor 1 upstream.

I replaced it, and after a little while it came right back. This is strange - one tech thought it might be the ECU but I really doubt that anything occurred. The wiring looks good. Having this looked over as well. Battery reads 12.5V cold soaked, and the wiring harnesses all look GOOD which is crazy. The shop will ohm out the O2 sensor and do some further diagnosis. I still have a little misfiring upon cold startup only (no engine light other than the P0031) and honestly I'm a little skeptical of my first shop changing the seals. I wonder if I have an injector or two leaking.

 

Are you going to use the much simpler and cheaper one piece heater hose on the back of the engine that eliminates the metal bracket and bolt that's so hard to access?
I think I read that you are?
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Yes, I'll be planning to use T2H3431 to replace C2D5710 - I'm really hoping to find the root cause of the P0031 though, I'm confused as to how this would recur. The main relay didnt go faulty, I have no other codes at all when I run a scan with my Autel.

My hypothesis is that the coolant leak is damaging the upstream o2, but we’ll see