# 2000 Altima Clank sound when stepping on gas



## BillHoo (Nov 13, 2006)

2000 Altima over 350,000 miles. I noticed this week when idling in traffic. Everytime I step on the gas, I hear a metallic Klank! sound. No sound when I release the gas. Just a Klank when I step on it. Like the sound that would be made if you had a metal pot lid upside down on concrete and you just stepped on it.

The sound kinda sounds like it's coming from under the car near the engine. I've looked there and do not see anything out of the ordinary.

Anybody ever had this before? Trying to isolate this so I can troubleshoot before it turns into something bad. Otherwise the car works fine. I can only imagine after 17 years of driving maybe a connector is loose or something wore out and fell off, or just needs tightening.


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## rogoman (Dec 16, 2004)

Most likely there are one or more broken motor mounts.


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## BillHoo (Nov 13, 2006)

Most likely.

My dealer used to replace my motor mounts every other year and charge me $550 each time. Car was under 100K miles.

I asked if it was normal to do that so often, he said no... they really don't do much, so you don't have to.

So now, I'm going on 300K miles and haven't changed them since 2007. so I figure it's probably due for new mounts.

I think I'll tackle that myself one weekend.

Thanks!


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## BillHoo (Nov 13, 2006)

I ordered a set of motor mounts online for $80. I shoulda popped the hood first to inspect before ordering. All the motor mounts appeared in good condition.

I was able to jack up the car and crawl under last month. 

Turned out to be the catalytic converter. Neck of the converter pointing toward the engine had corroded and broken off - but not completely.

Metallic clunk was sound of it occasionally clanking against the pipes as it bent in a scissor motion to the remaining metal.

I had to debate whether to buy a new one for a car I only plan to keep another year. Or just repair.

The neck had corrodeed almost all the way around with less than 7 percent of the metal remaining for the clamp to hang on to. It was hanging the way a the lid to a tin can would hang if you just cut around the can and bent the lid back a bit, not pulling it completely off.

I removed the cat and used a wire brush wheel on a electric drill to remove all the rust on the outside and inside. By now tha remaining 7 percent was probably less and just a little thicker than tinfoil.

Looking inside the cat, the insides looked intact. I could see through the honecomb with no blockages.

I had an old Harbor Freight flux core wire welder I had gotten years ago and never used. I figured what can I lose? I can try welding it back together!

Aligning the tow piece best I could I found that it was like a serrated knife edge all around. In as much as 40 percent around, there was a 3mm gap. To bridge the gap between to two edges, I took a wire coat hanger and sanded off all the paint/enamel.

Carefully, I tack welded all the edges that were already close together. Then, I welded the wide gaps with coat hanger in the middle to bridge them.

First time welding, so it looked really ugly.

I would stop occassionally and hit the welds with a hammer to chip off the slag and use the wire brush on it.

When I had completely gone around, I held it up to the light to look for pinholes and welded those closed.

Looked pretty good.

I got two new gaskets and some Permatax Copper Hi temp sealant and some new bolts to clamp it back together. Waited 24 hours for the sealant to cure.

Took it off the jack and drove it around - no leaks!

It's been doing great since then.

Now I have to get around to return the motor mounts.

Harbor freight welder has paid for itself on it's first use. I had gotten it on sale for $90. I think the cat I wanted to buy was going to cost $80, not including labor.


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## BillHoo (Nov 13, 2006)

As mentioned... going on over 300K miles on the original cat.

Back when I was at 69K miles, I had a the muffler come off and brought it in to a Midas to put it back on. They gave me an estimate and recommended that the cat be replaced because "the item is nearing the end of it's useful life". They wanted to charge me $1000.00!

I told the guy "no. put it back on". He looked like he was going to have a conniption! His face got red. But he put it back.

Over a 240K miles later and so far passed every inspection.....


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## BillHoo (Nov 13, 2006)

Just some photos of my handiwork if anyone cares to see my ugly welding job.

The flange barely holding onto the cat by a sliver of metal.









A piece of the converter honeycomb that I found in the exhaust pipe. 60 percent of the material remains in the cat.









Looks pretty clear looking through the honeycomb. I've heard of people washing out the cat by soaking overnight in a bucket with dish soap. I'm not bothering with that.









A look at my ugly welds from the outside.









I had also welded some pinholes on the inside.


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## BillHoo (Nov 13, 2006)

It passed the safety Inspection in May. But the heat shield rusted away and fell off last week when I ran over a speed bump.

I shoulda tack welded it a bit while I had it off the car.


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