Smoke test to identify exhaust leak (ticking sound)

[abuck99]

I don't vape but based on the amount of smoke I see some dudes exhale- I'd say there's no trouble with volume

anyway it was an out of the box idea.vape
Pens are cheap.

I would use mineral oil -and find a suitable method to get it to smoke- it's going to be cleaner than most any other of your proposed choices. I think veggie oil would leave a residue and hard coat or produce more soot.

Instead if coals try using one of those warming tray tins it's called chaffing fuel or sterno.

 

[sean2202]

Here's a clue: It's your manifolds that are ticking. Unless you are planning to repair them with a welder, just replace them with DT headers. No smoke required.

Did you replace your manifolds with headers? If so how are they holding up? I have never had good luck with any headers and I have used a bunch from cheap ones to very expensive ones. I replaced my manifolds on my cruiser with stock ones.

 

[CanadianRockyCruiser]

Did you replace your manifolds with headers? If so how are they holding up? I have never had good luck with any headers and I have used a bunch from cheap ones to very expensive ones. I replaced my manifolds on my cruiser with stock ones.

I had the classic "ticking" sound on startup (a sign of an exhaust leak from the manifolds, typically at the welds). It would go away as the metal heated up. I replaced the manifolds with Doug Thorley Headers, as many others have done. My headers developed a similar problem, but are covered by warranty from DT. I got an early batch, which I understand had problems with some of the welds. Apparently these problems were resolved in subsequent DT batches.

 

[sean2202]

@2001LC in the past on other vehicles I used a spark plug to block off the o2 sensor in the manifold. Not sure if that might work here. As far as the two under the truck you could probably take them off if the nuts are good and make a block off plate out of metal with a high temp make a gasket cork board.

 

[2001LC]

If the real goal is to find the source of the ticking sound, then why not use a mechanic's stethoscope?

I have, just can't pin point.

Test #1: Smoke machine total cost $3 for fully bottle of mineral oil, plus stuff lying around the garage.
I ended up using mineral oil, soldering iron and tiki torch wick. Produced a good amount of smoke lasting for 30 minutes with ~1/2 oz of oil & 6 " wick. Not finding any leaks, I can't be sure I produced enough pressure (bucket is a bit leaky) into exhaust system. So not sure if no exhaust leak or need to refine my smoke a machine.

I did use for about 30 minutes without setting off a CEL for o2's or cat's,.

Bucket is a bit leaky

 

[camino70]

Have you measured your valve clearance yet?

 

[Julian Stead]

Unless you take the cams out of the cylinder heads you probably won't build up enough pressure to smoke test as it will escape into the intake. You would be better of putting a rag over the exhaust to cause back pressure and see if the ticking note changes or if the leak is visible.

 

[2001LC]

Have you measured your valve clearance yet?

No but that is a consideration. If I can't find it, I may take to Slee or Dealer to isolate. If they say lifters I'll then open it up. But the sound is very much like I recall my LC DS sounded like, before Dealer replaced exhaust manifold under TSB/warrantee.

Unless you take the cams out of the cylinder heads you probably won't build up enough pressure to smoke test as it will escape into the intake. You would be better of putting a rag over the exhaust to cause back pressure and see if the ticking note changes or if the leak is visible.

Thanks Julian, I'll give that a try also. On first compressed air pressure test I could hear air coming from exhaust value out from intake manifold. This new box may give me enough volume and pressure for the job. Is there any crank/cam position where all exhaust valves are closed?

Redesigned smoke box.
(Updated OP with same pictures.)

 

[Julian Stead]

If you set the crank to the timing belt change mark and not the TDC mark you might be ok. You won't have a position so that all exhaust valves are shut but you will have a position when only one valve is open at a time in the cylinders, the inlet and exhaust valves overlap at the end of the exhaust stroke close to TDC so setting the belt to just after TDC should be ok. Just turn the crank slightly if you hear the air coming out of the intake manifold. Hope it works for you..

 

[2001LC]

Is there a part number that indicates year of manufacturing stamp on replacement exhaust manifolds. Anyone have one lying around or in stock they can look at?

I finally got time to looking again for my tick. BINGO

This time my smoke machine redesigned with fittings (no tape) held pressure really well. Was put out a good amount of smoke too. Again I could not see any smoke. Possible a better light would have helped. I was able to faintly hear a hiss, difficult as compress was sitting near PS, but sound appeared on DS.

Hearing hiss, I then turned crank shaft to see if pitch would change, it did not. So I assume this was not just air passing by exhaust valve.

But I really wanted to pin point the tick, so grab a spray bottle & dish soap. I turn up the air pressure to 40 PSI and started spraying from underside rear working my way forward (less water in the face). Couldn't see anything.

I then started at front top side from wheel well, Bing go. I saw something on #1 tube at weld, but was very faint. I grabbed up some more flashlights (LED) and drop light. Using a mirror to get a better look., I spray a ton of soap water on area. Although faint, I'm now sure it's nothing more than the typical weld at tube to manifold plate leak.

I was sure of this leak being DS on first inspection. @Ali FJ80 first though was this as well. But what keep me looking, is, I wanting to pin point. MyLexus records for this vin # shows Dealer replaced. Christo at Slee Off Road said to me once; "they've never seen one leak again, once it's been replaced" nor have I. My concern has been that this could be valve gap (not a big deal), or something serious internally.

The tick goes away in 90 seconds after warm up, so not concerning since I now know what it is for sure.

So is this a fluke, did Lexus Dealer use old stock or was the issue never corrected and just charge to PO???

Unless there's a part number on it, that indicates year of manufacturing, I'll never know.