RetroJohnny

"Clashing" Sound when Accelerating

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Hello everyone! I haven't posted in a while, which means no problems ;) but this is more so of a curiousity question instead of an issue. When I accelerate, mainly 10-45 MPH, there is this very faint clashing or "gurgle" sound. It has been like that since I got it I beileve. It doesn't seem to degrade preformance, and I really dont think it's the coolant system bubbling, which can be a common gurgling sound. It really is hard to explain, kind of like a very faint snare drum, crazy right? Am I crazy or is there something really going on here? Thanks!!

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I similar sound when my car accelerates. The sound I hear is more of a tinny, rattling sound. It's been there for several years. I agree with Harry. I think it is coming from the catalytic converter. I hear it much louder when driving beside a building where I hear the echo.

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I'm leaning toward it being the catalytic converter, also.  I've had a couple of cars over the years with the "rattle", and it always turned out to be the converter. 

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So if it is the Catalytic Converter there's no pressing issue. Or something I should have to replace? I think I can live with a little rattle if it isn't really hurting preformance or longevity of the car.

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I'd keep an eye on the water temperature gauge, that's usually  a good indication if things are not going well. I had one go out on my Ford escort wagon. It would rattle for about a month then one day coming back from the coast of Texas , the temperature started to go up and performance started to bog down at a stop light. Then I heard a big bang, it blew the guts of the converter out the tail pipe, but I was able to get back home. When I bought my Reatta I went ahead and changed out the cat and muffler to be sure of no problems. The car had 120,000 miles on it, probably did not need to do it, but that's just me. 

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6 hours ago, bikemikey said:

I'd keep an eye on the water temperature gauge, that's usually  a good indication if things are not going well. I had one go out on my Ford escort wagon. It would rattle for about a month then one day coming back from the coast of Texas , the temperature started to go up and performance started to bog down at a stop light. Then I heard a big bang, it blew the guts of the converter out the tail pipe, but I was able to get back home. When I bought my Reatta I went ahead and changed out the cat and muffler to be sure of no problems. The car had 120,000 miles on it, probably did not need to do it, but that's just me. 

Well mines stays around 190 degrees, but when idling it can get up to 210 degrees. Thats the hottest I've ever seen it. I have always just thought that temp increase was normal while idling.

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After thinking about it , the temp gauge on the Reatta probably isn't the best barometer for telling you something is wrong. My gauge can wander all over the place on my 89. Living in Texas, I've seen my gauge go up to 233 degrees on a hot day with the air on and at a stop light. I was thinking more in line with other cars I have own. For example, when my Ford Escort reaches operating temperature it stays put, no matter what, unless something goes wrong. But that is not the case with the Reatta. Sorry about that.  

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When sitting stopped in traffic the temperature will creep up to around 230 degrees before the cooling fans will kick in to high speed and cool the engine back down. The engine is designed to operate at that temperature. You can have the ECM PROM changed to have the cooling fans kick in at a lower temperature. I have installed a relay in my '88 that is activated by a temperature probe. The relay that kicks the cooling fans into high speed at 190 degrees but reprogramming the PROM is the better way to go.

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If it's the cat, be careful. I had one of mine collapse internally and kill the power output from the engine (exhaust couldn't escape) until I removed and replaced it. If it's rattling now, a collapse of the internal catalyst is likely to occur, assuming the noise you're hearing is from the cat.

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6 hours ago, Imperial62 said:

I would consider purchasing an automotive stethoscope.

 

Thanks for all the suggestions. I do have a stethoscope but I've not had any success pinpointing the source of the noise I hear. It only seems to occur when the car is in gear and accelerating at a moderate pace. I have checked the heat shields but nothing about them seems to be loose or rattling. Rust isn't a problem here in Tennessee where I live so rusting parts isn't a factor.

 

The catalytic converter on the Reatta is welded to the pipe on both ends. I hate to cut it off and replace it with a straight pipe until I'm sure it's the problem but if the sound gets any worse I will. Or I might replace it with a new converter with the pipe that goes all the way up to the engine. That way only one splice in the exhaust system will be needed and it would pass emission tests in other states if I sold the car. We have no emission testing here where I live in Tennessee although it is against federal law to remove the converter and replace it with a pipe.

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On 3/7/2018 at 10:53 PM, Ronnie said:

 

Thanks for all the suggestions. I do have a stethoscope but I've not had any success pinpointing the source of the noise I hear. It only seems to occur when the car is in gear and accelerating at a moderate pace. I have checked the heat shields but nothing about them seems to be loose or rattling. Rust isn't a problem here in Tennessee where I live so rusting parts isn't a factor.

 

The catalytic converter on the Reatta is welded to the pipe on both ends. I hate to cut it off and replace it with a straight pipe until I'm sure it's the problem but if the sound gets any worse I will. Or I might replace it with a new converter with the pipe that goes all the way up to the engine. That way only one splice in the exhaust system will be needed and it would pass emission tests in other states if I sold the car. We have no emission testing here where I live in Tennessee although it is against federal law to remove the converter and replace it with a pipe.

You may want to check the condition of the rubber on the harmonic balancer. My 90 olds (3800 engine) was making a clacking sound at idle and that was what was causing it. ($90.00 at O' Reilly's Auto Parts) 

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The balancer is in good condition. I have changed it and it doen't have many miles on it. The engine is quiet at idle. Thanks for the tip.

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