Tick-tick-tick on cold start under load; exhaust manifold or...

[tonydyvr]

So I`ve noticed a repeating tick-tick-tick noise from under the vehicle when the vehicle is under load, especially when it is cold.

It is not a pre-ignition pinging, rather an extremely consistent tick, much like a metallic playing-card-in-bike-spokes. It largely goes away when the vehicle warms up.

From what I have found online, it sounds like a cracked or leaky exhaust manifold might be the culprit. Two questions -

1- Aside from finding a pressurized smoke machine to flood up the tailpipe, I am wondering if anyone has any diagnosis tricks to look for this problem. I`m thinking if someone puts their hand over the exhaust pipe end when cold, whether you`d hear a hissing from under the vehicle, or if it gets lost in the other assorted engine noise.

2- If there is cracked manifold(s) issue, then what is the prognosis for just leaving it on and ignoring itÉ It sounds like if I can smooth-talk my local welding buddy then he might just be able to run a bead along it if I pull it off, but at the moment it is just an irritant. Are there any kind of catastrophic failures that can happen if the crack(s) get worseÉ

Thanks.

 

[Grego]

The only way I would recommend narrowing it down would be with a stethoscope. They usually crack around the bolt flanges that screw into the block. Impossible to see the crack when installed. New replacents are only @ $200. I would not do the job twice to save a few bucks.

As far as letting it go, it will probably slowly progess to a more constant tick but I feel like it would have to go a long time and get pretty bad before it did any internal damage to exhaust valves or whatnot. I couldn't take the brief tick on mine when cold and swapped it out in about a half a day.

Hopefully it is the passenger side, steering linkage makes the ds a little more of a chore.

 

[CreeperSleeper]

Sounds like the exhaust manifold to me. You could also use Seafoam to find the leak and clean your engine at the same time.

 

[Wilsil]

I have a similat tick since I bought the car almost 3 years ago.
My mechanic told me it is a crack in the header which closes up when the engine is warmed up.
It will give me an excuse to install extractors soon.

 

[GaFJC]

Yep, exhaust manifolds. Folks have had mixed results with Doug Thorley aftermarket replacements. I don't know where they stand with emissions cert in California either.


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