Hi everyone, new member & new Disco owner here! I purchased my 2004 Disco II (118,000 miles) a couple of weeks ago and have been combing this forum for advice on things to address right off the bat to head off as many potential issues as possible including: changed oil to Rotella 15w40 T4, topped off coolant with green stuff but will flush & fully replace coolant while installing new 180 degree thermostat (received today.) I plan on following some of the forum posts here for bleeding the system properly. Ordered Ultraguage & should be receiving tomorrow which I'll pop on before replacing thermostat to get a before/after on coolant temps. I also pulled a ton of old leaves out of my ac blower motor so it no longer sounds like a tornado when I flip on the ac. Next on my list include checking whether my driveshaft needs to be replaced with a serviceable one.
All that to say I have found this forum very helpful so far!!

Issue: I get this flapping/ticking noise which is consistent (doesn't sputter) but speeds up as I get moving & when accelerating. I am putting text links below because I am a new member & I understand if I post links or videos within my first 10 posts they get moderated. In the longer video the sound becomes more noticeable around 30 seconds when I move to the engine bay. I'll try & follow up with a video from a cold start because it is pretty noticeable from inside the cab on a cold start but less so in these videos.
Based on some of the forum posts it seems like a good idea to check the u-joints which is on my list anyways - but the noises I've heard on posts where people recommended that sounded different to me so I'm not sure. I plan to purchase a stethoscope to try & isolate the sound more - for now it sounds like it is coming from right under the driver footwell & is most noticeable on the driver side of the engine bay. Thanks in advance for any thoughts!!

 

Well, I'm seeing that the forum picked up my links anyway, but it seems to have worked okay (?)

 

My guess is possible exhaust leak? A crack somewhere on the driver's side exhaust manifold? Or loss of seal integrity either between the manifold and cylinder head, or the manifold and the y-pipe?

 

Yeah, sounds like an exhaust leak. Could be SAI tube, very fragile and known to crack, y-pipe flange is another known problem child. While running, take a rag and try covering areas to see if noise becomes more muffled...be careful though...things get might hot quickly.

Those SAI tube check valve can go bad too, and make a ticking noise, cover that too, with a rag and see if there is any change.

 

Thank you sirs, I will investigate. I had sprayed the exhaust system down with soapy water & only found a small leak on the passenger side manifold to y-pipe gasket, but that's not the source of this noise (& doesn't mean I didn't miss one on the driver side). I will look further at the exhaust components & check the SAI system as well. I'll post what I find out! Thanks!

 

rocker arm tick or exhaust leak....

 

Shove a leaf blower or a shop vac on the blower setting up the tailpipe with the engine off, spray the exhaust with windex, any leaks will show as bubbles.

Read the inline thermostat sticky, send that factory thermostat back and do the inline mod, trust us, you will be glad you did.

 

Down pipe gaskets. Sounds like a 4 cylinder leak.

 

It is quite common to have the Y pipe develop a leak just below the exhaust manifold flange... So if your gaskets there are good, be sure to check the state of the actual pipe around the flange weld.

You may already know the shop vac trick... Run the hose from your shop vac exhaust outlet to the trucks exhaust pipe, seal it up with duct tape. (engine off as in not running!) Then go feel all around the exhaust manifolds and Y Pipe gaskets.

If you want an excuse to smoke a cigar you can also blow a bunch of smoke into the vacuum inlet while someone looks for it in the engine bay or underneath.

 

Update: The leak was (I think) in the driver side SAI plumbing. I bought the wrenches I needed to pull the SAI tubes and found a tiny hole between the corrugations on the underside of the SAI tube right near the hex nut, bout 1/8" diameter. I put some JB weld on it and will see if it will hold. Driving it this morning there is still a sound but it seems to be coming from the passenger side now and is maybe quieter. My theory is that that SAI tube is also leaking, or the exhaust gaskets on that side are gone (I replaced the driver side gaskets but not passenger side).

Thanks for the advice!