Over the past two or three months I've noticed a brief, deep, rumbling sound - like a loose heat shield (so I'm told) - coming from under the car just just as it accelerated from stop, under load (hill or incline). Doesn't last long and is most noticeable when the engine is cold.
I used to think it was coming from the back so I put a piece of foam just behind my rear license plate when I washed the car last and heard what I thought was a similar rattle when the sponge caught a corner. My imagination must have made it go away...for a day or two. Then I began hearing it again.
It does seem to have grown louder, though, I doubt if the noise can be heard by someon outside as I pass them. Today I tried focusing on which end of the car it was coming from. With the sound lasting no more than three or four seconds, I located it in the front, underneath me, and in the back again. In short... I don't know where the hell it's coming from other than under the car.
A friend who has some experience in these matters ruled out a leaking head gasket and exhaust manifold gasket; two nightmare that could throw my little "renovation project" with this beast into the category of "no longer cost justifiable."
My hopes were renewed when those cradle bolts were replaced without incident and I began looking forward to holding onto this car and replacing struts and tires knowing full well I'd be faced with an air compressor maybe next year or the year after. If this noise turns out to be something significantly expensive, I'm going to have to rethink everything. Hope that's not the case. I've grown fond of the car over the years though I wasn't so five or six years ago.
Would appreciate receiving a list of things this noise could most practically be so I can decide if that vocational school could tackle it. I doubt if I can even get it in for them to look at ''til after the holidays.