Hello,
I have a 2003 CRV. everytime I start up and warm up the car, after 4 minutes of idle time, in park, I start to hear a knocking, growling noise, It has no rhythm. When I start to drive it goes away and then sometimes it comes back. So it is present when not driving and when driving the car. I hear it when I am in the car and when I open up the hood, I don't really hear it, but I feel a knock or vibration on the drivers side fender.




I went to the dealership and of course, the sound was not present. I went to a mechanic, and of course the sound was not present again. However, they said it was the serpentine belt and replace it with the tensioner. And then the next day, the sound came on. I went to the dealership and they never heard the sound but checked the car and replace bearings to the tie rod ends, rt shock front and back, and the front engine mount. He checked the radiator because I had noticed the reserve fluid low which is unusual, but said there were no leaks.


I have done now the serpentine belt, tensioner, had a non Honda place replace the transmission fluid, steering fluid, spark plugs, and did a exhaust clean up ((all 9 months ago)).
Any one have this problem or have some suggestions? I still have not been able to get a mechanic to hear the sound that I am concerned with.


Thank you!!

 

I've actually ran into this in a 90s Mopar, and I know it's going to sound crazy. This may not be the issue but it's a thought. Locate the heater core hoses when the vehicle is making the sound. If the sound is coming from the same relative area give or take a foot in either direction, it's probably a small air pocket in the core. It won't hurt anything, and may rectify itself but if YOU wanna try to get it out I'll give you my way. But if you take it somewhere you'll get looked at like a nut case because I didn't even believe it until I did everything else and spent a ton of $ and time.
First, make sure your vehicle isn't even warm, let it sit 4 hours after it was last ran. 2) carefully remove both heater core hoses from the block (if possible, but 1has to be done at the block) 3 slowly add coolant to the hose that's connected to the core (at the fire wall) and if you're lucky it'll help move the air pocket. The other few ways involve either having a decent size air compressor or removing the core itself (something I dread as a guy who wrenches for a living) and go from there.
Good luck buddy,
Mike da wrench 😎
C.O. Crew