noise symptom. Somebody always chimes in with the “loose heat shield” … Not every darned car produced with a heat shield is loose!! Have you ever tried to take one off? Secondly a mechanic would have to be blind not to see one loose or contacting an exhaust component.
Enough of the catch all clunker reason.
Yeah but I’ve had them come loose myself and they can make a heck of a racket and not always easy to tell where its coming from. They don’t fall off very often either, just break a fastener or two and rattle away at certain times.
“Enough of the catch all clunker reason.”
Yea, not all clunks are caused by a heat shield, but a lot of them are. Often they are not hard to check.
If someone is experiencing the clunks, then checking the heat shields is a logical approach.
It’s VERY VERY common…Happened to both my Pathfinders…my wifes 96 Accord…and a couple of my sons friends cars…Most cases it was just easier to remove them…or clamp them. It’s so common…it’s on the list list of the first things to check.
I don’t think I have ever had a car on which the heat shield DIDN’T break off and make noise.
On that note, I have NEVER had or known anyone who had problems with a motor mount or transmission mount. (Tom and Ray’s other favorite diagnosis)
Mr. Obvious Here:
Depending On The Nature Of A Mysterious Noise It Makes Sense To Check The Easiest Things First Before The More Difficult And Heat Shield Checks Usually Qualify As Easy.
Obviously if the problem is not found in the heat shields then one has to check into other more difficult to check areas.
Binkman said it herself/himself. The idea that " . . . a mechanic would have to be blind not to see one loose or contacting an exhaust component." supports this basic diagnostic procedure. Rule out the easiest, most obvious things first.
CSA
I’ve never heard Tom and Ray answer “loose heat shield” for a clunking or grinding noise. It’s usually the answer for a rattling noise though. Likewise, I’ve never seen (or heard) a loose heat shield do any thing but rattle. If I was looking for the cause of clunking or grinding noises, I would start with the drivetrain and suspension components, but it would have to depend on the symptoms of the sound (when it happens, whether it ever stops, whether it changes pitch, etc.). The characteristics and behavior of the sound should impact the answer as much as the type of sound.
mleich wrote:
On that note, I have NEVER had or known anyone who had problems with a motor mount or transmission mount.
On a mid-2000s Honda or Acura, this is a reasonable possibility.
Binkman, Are You Referring To Advice Given In A Recent Discussion In Which You Took Part ?
http://community.cartalk.com/discussion/2280996/grinding-noise-when-decelerating#Item_4
OK4450 suggested checking for heat shield noise in this same discussion, but I don’t believe he based this decision on anything said by Tom or Ray. He doesn’t need the help.
He is an experienced mechanic and I value his advice and opinions very highly.
CSA
I haven’t listened to T and R in 20 years so my opinion is based strictly on personal practical experience; not on a radio program or newspaper column.
I don’t equate a clunk with a heat shield problem but do frequently associate a rattle or grinding noise with a heat shield fault. Heat shield faults are common because you’re talking about thin sheet metal that is exposed to much water, salt, road debris, and is subject to repeated heating and cooling cycles.
The frequency of exhaust vibrations can even make a rattle sound like a grinding noise.
Heat shield problems are common enough that sometimes car makers even issue TSBs on them. Subaru even issued one many years ago and their recommended fix was to insert a sheet metal screw into the shield so it would bottom out against the inner pipe. Comparatively crude but it worked and was much faster and cheaper than replacing a very expensive header pipe.
You refer to someone having to be blind if they’re not able to see a heat shield fault.
That would be incorrect because some heat shield problems are not visible due to a hidden out of sight microscopic crack or one loose spot weld.
The Mazdaspeed people have complained for awhile about the factory motor mounts, and usually recommend replacing the rear motor mount with an aftrermarket one(a couple vendors on the forum sell them). Have heard of a few cases of the motor actually banging against the firewall if they hit the gas too hard and shift
“On that note, I have NEVER had or known anyone who had problems with a motor mount or transmission mount.”
Both my last two cars did: '83 GTI, it’s a common problem with that era VWs, followed by my '96 ES300, let the engine rock to the point it cracked the radiator tank, so had to replace that, too, but at 12 years I expect that kind of problem.
Back to the OP’s comment - check the cheap stuff (loose heat shield) before moving on to the expensive stuff, a rule I’ve occaisionally ignored, to the detriment of my wallet!
Didn’t mean to “rattle” the cage so to speak. It must be more northern climate related, salt, ice and snow. I’m from the mid Atlantic ‘Piedmont’ and we don’t see that much snow or salt I don’t go to the shop daily anymore as things run smooth with staff etc. It is a repeat biz shop but we do a lot gen. temp or tow in work, too.
Okay… Just from a general inspection perspective. We have microphones and headsets I provided to test drive the noise complaints. (southerners are picky as hell about noise as the heat is intense and windows are usually up.)
I did ask the 3 mechanics we have, the number of obvious loose heat shields they’ve seen in the last 6 months. Aside from the fact they looked at me like I had a snake on my head… guessing from the top of their heads… the total was about 4-5 a piece. Not counting “missing” they don’t look for it if it’s not there.
A rattle is not a clunk nor grinding noise. And the roads down here are not strewn with heat shields so it must be climate related.
“It must be more northern climate related, salt, ice and snow.”
That I can agree with. I’ve never seen it in the South myself unless it was on a car whose owner recently relocated from a northern state.
I think the comment about roads being strewn with heat shields is a bit much. If there’s 3 guys there who have seen 4 to 5 apiece in only 6 months time then I’d say it was a common problem.
Heat shield rattles have been around pretty much since the advent of catalytic converters.