noise under car when it rains

I have two Camrys, A 1993 and 2001. Both cars have 4 cylinder and automatic transmissions. When ever it rains heavy and I am on a highway or fast moving road 45 mph or better. I hit a groove on the road that splashes water under my car. Then I get a rumble from underneath my car as I drive the rumble gets less and less as to water got wet seems to be drying out. Until I hit another groove and splash water under my car again. Both of my cars do this. Is it the cat getting wet (if not what is it then) and if so what can be done to correct this.

On my 99 Camry there is alot of plastic shielding around the front and in the wheel wells. A piece is probably rattling when it's pelted by rain. When I first purchased this car and drove in rain, I was amazed at just how much road noise I could hear. I think your probably just hearing the same sounds I hear, but get down underneath and check all the plastic shields for tightness. Make sure that all the hold down clips are in place and snug.

Bill I diubt it is the shielding. something gets wets underneath the car body then it sounds like the muffler went bad. as what ever got wet dries up the muffler starts to sound normal.

I have that same thing happen on my 2000 Camry 4 cyl. During hard rain, it sounds like the muffler is coming loose at a connection or something. I also notice a reduction in power, too--at above 45mph, or so.

I've been looking for the cause and I've wondered if it might have something to do with the ABS. I've thought the sound could be from the system noticing a slight "slipping of one wheel, due to the water on the road, and somehow starts the ABS actuators. It would make that kind of noise I would think, and would also account for the reduction in power if the brakes are being applied slightly. I don't really know, though. This is speculation on my part. I would like a definitive answer, though.

any ideas anyone?

bigrick7,

Just a guess here, but both cars could have a slight crack somewhere in the exhaust system. Follow my thinking here. If the car is warm, the heat from the exhaust system has caused the system to expand and close the crack. The water causes the system to cool rapidly, opening up the crack again. Then the system's own heat evaporates the water, and as the system reaches it's normal hot temperature again, it expands again and the crack again seals. If this is it, it will get worse over time and will be easier to find. One other thought as to finding the crack; when the car(s) is(are) cold, start it, then stick a rag over the tail pipe and listen to see if you can reproduce the sound and determine where it is coming from. A second person to either hold the rag over the tailpipe or to listen at various points along the exhaust system might help here.

Good luck with the problem.

Mike

I had this problem now for several years. if it was a crack the problem should get worse. but this only happens when the underbody gets wet. then it sounds like i lost my muffler. then it dries and the car running great again.

I'd thought it might be a problem with the exhaust system, like a crack, or a loose connection that opened when the cold water hit it, But I couldn't reproduce the problem on my 2000 Camry with the engine warmed up and running and hitting the exhaust with a stream of water from a hose. Only when you're running and there's lots of water on the road. It hasn't gotten any worse over time, either. Good idea, though, Mike.

bigrick7, do your cars have ABS, by any chance?

dom, yes both cars have abs. but I almost positive it is not the abs. when I get the noise i ease off the gas then the noise quiets. as i hit the gas noise gets louder. when the under body gets wet I get a knock were the cat should be then it sound like the muffler fell off. but then she dries and shes running and sounding great again. this is both of my cars.

Yep, the symptoms are identical on mine. Also when you give it gas, the noise does gets louder (possibly from under the passenger compartment, but it's hard to tell) and there's a definate reduction of power. That's why I thought the ABS might be involved. I don't know what else to consider. The Toyotas I have owned and currently own without ABS have never done this.

My 99 Camry also does not have ABS and I do not have any additional noise when driving in rain. You guys may be on the right track. It might also explain why wetting the car with the hose did not reproduce the sound... no brake movement. Curious problem indeed.

over 85 views, and still were at square one.

Check the seams on your muffler (front, back, and sides) and see if it might have a bad one. Cooling the bottom of the muffler might make the bottom contract and the seam get loose/make noise. That would explain why it only does it when your driving, the muffler is quite hot then. Letting off the gas would make the exhaust quieter under all circumstances.

You could try Brian's idea with a garden hose after the car is hot. Have someone rev the engine to simiulate the RPM's when this occurs while you are driving while a second person sprays down the car starting with the muffler and then moving to the other area of the exhaust system until you find where the noise is coming from. I would try this now (this time of the year) while the water is still around the ambient air temperature.

Mike

All,
I'm new here and this question really caught my attention. My wife has a 98 v6, it make the same sound as described by Big Rick. I'm no mechanic but, I honestly believe it has nothing to do with the exhaust system. Call me crazy but I think its the alternator. The alternator is mounted on the right side of the car, it appears that water can easily get into the alternator while driving in wet conditions. That's my thought on this hole noise thing.

homerun

If it's the alternator, what's special about his and yours that makes it noisy when 10,000,000 others don't make noise? This is a defect problem, not normal.

I don't think it's a defect. I think there might be a loose or broken plastic shroud under the car which allows water to enter the engine compartment.

OK, well therein lies the defect :)

Replace the defective shroud and the sound should go away if your assessment is accurate.

Did anyone find a solution to this problem? My 2000 Camry CE does the same thing when it rains hard, and it does not have ABS, so I am doubting that the brakes have anything to do with it. Just wondering how I can fix it.

There may be multiple problems with similar sounding symptoms. Since you can't hear their cars, their sound in the rain may be totally different than yours. Beware of generalizing and wasting money. If the solution is cheap, no harm, no foul. If it is expensive, then be cautious.

No solution yet. My 2000 Camry LE still does it whenever there's a lot of water on the road, like from a heavy rain. Can't reproduce it with water hose. I think a load has to be on the engine to notice the reduction of power. It does sound like an opening up of the exhaust somehow. Just like when it get's wet, part of the exhaust system (a connector maybe) contracts from the cold water, then the heat expands it back again and quiets it down again.

Very odd indeed.

No solution yet. My 2000 Camry LE still does it whenever there's a lot of water on the road, like from a heavy rain. Can't reproduce it with water hose. I think a load has to be on the engine to notice the reduction of power. It does sound like an opening up of the exhaust somehow. Just like when it get's wet, part of the exhaust system (a connector maybe) contracts from the cold water, then the heat expands it back again and quiets it down again.

Very odd indeed.

I own a 2001 Toyoat Camry, and have the same problem with rain soaked highways. When the car drives thru the puddles in the worn spots on the road, the engine starts too act like the car is hydroplaning
and a banging noise is felt under the drivers seat. Had the dealer check it out during a routine service. Told me he tightened somehting up and it would be OK. Well it was for a few months and it started again. Took it back and they said they couldn't find anything. My warranty run out in 2006. Hope this dosen't turn into a few thousand dollar problem. Any ideas out there?

Tell them to tighten what they tightened the first time then tell the rest of us. I am really dissatisfied with the amount of road noise. It gets worse as the miles get up on the car. I am currently at 92,280 miles. 280 miles over the oil change Eeeks. I tend to be a perfectionist when it comes to my rides(cars and horses).

Tell them to tighten what they tightened the first time then tell the rest of us. I am really dissatisfied with the amount of road noise. It gets worse as the miles get up on the car. I am currently at 92,280 miles. 280 miles over the oil change Eeeks. I tend to be a perfectionist when it comes to my rides(cars and horses).


This is what the service dept. typed on the servive entry,

Check rattle quick stop & banging noise
control arm shift underload control improper torque
R&R control arms. Remove rust, lube & retorque


Whatever that means it worked for a short period of time, but is doing it again. Checking with service next time I go in. Will see what they say.

I recently bought a used 99 camry that has this problem. It's fine until it rains pretty hard then after hitting some puddles I get a LOUD rumble from the exhaust and knocking under the drivers seat.

Anyone ever find out the cause ?

Wow I came searching for answer as I have the same issue. I thought I was the only one lol... my car is a bit older 1992 Camry but still runs well except for this issue.

It is a strange one, only when it rains, I get a loud noise, it feels like the muffler fell off, gets louder when you hit the gas, mine only sounds loud at 80+ kmph and above. Same as above poster, LOUD rumbling and knocking under the seat.

When it is dry and warm no noise. Still cannot believe no one found the answer.

The answer to this is very simple; water hitting the underside of the exhaust will cause it to cool and contract. This means the entire pipe will bend away from the cooled area (usually upwards) and if there is insufficient clearance the exhaust will hit the body or suspension and cause the knocking/rattling noise until the exhaust heats up and bends back again.

**Solution found**

Hi , i am Sachin from India. I also faced same issue during rains in last few days. My car dealer(Hyundai) replaced my car silencer part(under warranty). Now there is no issue. It was related to silencer and exhaust. It was loose so It also used to create noise due to vibrations and jerks in rear part of the car.

Both problems are resolved with replacement of silencer.

Replacement of silencer may not be mandatory ask your mechanic to check if silencer or Exhaust is loose.

My 2000 Camry shakes and rattles, and makes a terrible rumble under the car when driving over 30 mph in heavy rain or slushy snow. I lose power too until I pull over and let the problem dry out after several minutes.
The car runs perfectly when dry. It is fine in light rains too.
I have replaced the belts, Engine Knock Sensor and had a baffle welded over the muffler to keep the cold water off the muffler. My mechanics are baffled also. They checked for cracks in the exhaust system, again nothing.
I have sprayed water under the car to replicate the problem but it only happens during heavy rains or slushy snow on the passenger side of the car. The Toyota dealer said they are not aware of a recall. Help.

Checked electrical wire harness where it comes out of the firewall. May have rubbed against the timing belt cover and exposed one of the many wires in the harness. Carefully cut the harness open. Found one tiny brown wire with a cut in the plastic insulation. Taped it up, then sealed the harness with electrical tape. Then sprayed Electromotive Cleaner on three of the contacts behind the engine's oil filler cap down low on the engine. There was some corrosion visible.
Car runs great now. The problem appears to have been electrical not mechanical. There was another electrical fuse of some kind near the harness described above so I taped it to seal it from water also. Hope this helps you.