I need help with a very concerning loud clanging/rattling noise coming from my 1997 FZJ80 (3 Viewers)

[edwards_rljr]

Don't hear much, maybe some belt whine??

Tell us again, when did you first hear the (current) noise (miles/months), any work performed before the noise started, how long have you owned the vehicle?

Can you get another recording (video) while standing outside, hood up, keep the microphone (phone) out of the wind coming off the fan and don't move the phone around quickly, ie: keep it steady where you hear the noise the loudest.

You didn't hear that rattling/knocking sound right before it starts running? I can hear the sound of the starter at the same time as the rattling/knocking sound, then the engine starts running and it doesn't make the rattling/knocking sound anymore after it's running.

I don't remember exactly when I first noticed this noise, but it has been doing it for a a few months at this point I guess. It doesn't do it when starting cold, but usually only after I have driven a short distance , such as stopping at the gas station, turn it off, then start it back up again after a few minutes, that is usually when I hear this noise. It has almost 219k on it.

I think I forgot to mention it in my first post, but when I was first having battery charging issues, a couple of years ago, I replaced the alternator, idler pulley and belts. No other work has been done since then, besides oil changes, until last week when the starter was replaced. I've owned this 1997 for 11 years.

I don't know that I will be able to get any better recording of it because it doesn't do it every time I start it. I will keep trying to record the sound, but I don't have anyone to help me , and I have to start the engine, so I can't be outside at the same time. Every time I've made these recordings I've been holding the phone out the window or had the door open. I will try to do it with the hood up and see if it's any louder.

 

[lumbee1]

That sounds like something loose under the truck is vibrating when starting. You really need someone else to crank while you watch/listen. I would also recommend pulling the wire to the distributor so it doesn't fire. From the videos, it sounded like the rattle got louder closer to firing the engine.

I found a rattle in the rear of my truck by hitting various spots with a rubber mallet. My rear exhaust hanger was rusted off and the exhaust was banging against the mount.

 

[clx16]

Ok so when you are cranking the engine rattles around more than while it is running, at least it does on all of my vehicles. check all along your exhaust to see if anything is banging around it. Also check your heat shields to see if they are rattling around.

It is hard to get sound on a recording device, but just to give you a comparison of a noise i tracked down to my oil pump (the noise sounded like it was top end, but it wasn't).



Also if you have to do the recording alone, Start with the door closed and your seatbelt on. its hard for people to know what sound stands out with the beep and door slamming before. Try to eliminate all other background noise. Also maybe a recording with the windows up and with the windows down. also maybe get the recording over near the passenger window if you can.

Hope this helps.

 

[Kernal]

OK, I went back and listened again, slowed down the playback speed to 1/4, 1/2, 3/4. In the first video the (odd) noise starts at 6 seconds while cranking, sounds like a chugga chugga chugga, then some ticking (~typical/normal) and something like slight belt or bearing whine.

In the second video it occurs at ~4 seconds and lasts ~1 second, chugga chugga chugga which starts at the end of the cranking sequence ie: the moment
the engine starts/fires.

So something bumping/knocking/rocking into something else (?broken motor mount). An exhaust leak might be one possibility but then it shouldn't stop so suddenly ie: exhaust leaks at a gasket or flange can occur with a cold engine but they usually go away slowly as the manifold and pipes heat up.

Need more information: more video/sound clips closer to the engine, maybe get one or two from above (left/right) hood open, then from the left front wheel well and another in the right front wheel well (hear the exhaust manifold). Get down there yourself while someone else starts the engine.

Also watch the engine while it's cranking/starting, put your hand on the valve cover to see if you can feel any bumping/dull knocking, rocking of the engine, etc ---

 

[edwards_rljr]

Thanks for the replies. I will continue to try to get recordings of the sound, and will update if I can get some better quality recordings.

I forgot to say when I posted the clips, but on the longer clip, I revved the engine a couple of times just to show that it doesn't make this sound after the engine is running. It seems to run fine after it's started, so I wasn't really that concerned about the noise at first, and thought it might just be something loose, and not the end of the world, but it really started to concern me when I heard a louder, more metallic clanging rattle a couple of times. Again , it doesn't do it every time, and I haven't heard the louder, more metallic sound since the starter was replaced last week, and maybe it was two separate sounds that I was randomly hearing, i don't know. I'll just try to get some better recordings.

 

[ppc]

Have you checked the exhaust system looking for failed hangers allowing it to hit the frame?

 

[Kernal]

^^^Definitely ^^^. On a cold engine/exhaust system get down on your back and push UP on the pipes, the hangers on every 80, if still the originals,
are long gone (broken) by now. There's a rubber block that splits in the middle, replacement is relatively simple.

One (of many) previous threads on the topic:

PM # 17: check your exhaust system cushions

Been discussed in the past and just recently so thought I'd post this up for those that haven't seen it yet. My 97 model FZJ80 recently started getting a new vibration for example while idling in drive, foot on brake, more apparent when the engine idled up with the AC compressor coming on or...

forum.ih8mud.com

 

[majdomo]

Just read through. Sounds like something only bangs once the engine gets some momentum from the starter as it turns over. Check all the exhaust hangers and your engine mounts. Easiest way to check the mounts is to go to an open area without traffic, pop the hood, stomp and hold the brake while you try to drive forward (trans in D) and rev the engine a little bit. You can see if the engine flops up in the gap between the hood and the cowl. If it moves more than about 1/4" or so, your mounts are probably done.

Not a huge deal to change, either take to the mechanic or lift it up with a chunk of plywood to spread the load under the oil pan (watch the hoses at the firewall). Lots of threads to search on this. My 97 had two seriously busted mounts and it made a nice difference when they were replaced.