New clutch smell

[Spork]

I have replaced 2 clutches in my life, so my experience would be "less than a certified technician".  The first one was probably 30 years ago, so memories are fading.

I have an old junker pickup truck that is worth about the price of the gas in the tank.  I replaced the clutch a couple of months ago and I sometimes get that distinctive "burning clutch smell" after driving.

Random facts that may or may not matter:
* yes, the disc was well aligned
* yes, the clutch, pressure plate and fly were clean of oil and debris
* yes, the fly was resurfaced
* no, my left foot doesn't ride the clutch when driving
* yes, the clutch length was adjusted according to the manual
* This is strictly a farm truck.  2 months of driving is probably around 30 miles.  It is still a pretty new install
* about the same time the clutch was fixed, I also did a very kludge job patching a broken portal on the exhaust manifold.  I patched it with high heat JB weld and I know this is not a permanent fix.  (Refer to value of truck.)  It is possible this is the source of the smell, but ... it sure smells like clutch to me.
* I never smell it while driving.  It smells about 3 minutes after I stop driving.

I've googled around and seen both "if you smell burning clutch, you have a problem and it's going to disintegrate very quickly... Your hair is on fire and we're all going to die" and "A burning smell is perfectly normal in the first few hundred miles of break in."

I'll probably still get a mix of "gloom" vs "no problem" ... but what what is everyone's guess here?

[Greg]

A "burning clutch" smell a few minutes after parking would lead me to inspect the brakes.  You may have a sticking caliper or shoe(s) that get the disc or drum very hot, which then cooks the pads or shoes when the vehicle stops and the brake is set.

Or it could just be the new friction disc off-gassing.  A check with an IR themometer (check the discs or drums) will help.

[Spork]

A "burning clutch" smell a few minutes after parking would lead me to inspect the brakes.  You may have a sticking caliper or shoe(s) that get the disc or drum very hot, which then cooks the pads or shoes when the vehicle stops and the brake is set.

Or it could just be the new friction disc off-gassing.  A check with an IR themometer (check the discs or drums) will help.

I'll try that.  I've tried seeing if I can locate the source by sniff test... but that wasn't very successful.  I've had the truck since about 2007 and have never touched the brakes.  But I get no telling brake noises, so I hadn't thought to look there.

Would you consider new friction plate smell "normal" for the first few hundred miles or so?

[Forcus]

I wouldn't worry about it too much until some miles (including fairly frequent engagements / disengagements) are put on it. At least 200. Also the only way you'd have a burning clutch smell is (1) excessive slippage / operator error (I figure, not a factor here), or (2) another failure where the clutch is not engaged all the way. I've heard of pressure plate and throwout bearings that weren't quite dimensionally accurate doing this. You didn't say what the truck is but I've found this type of problem, the "parts books" being wrong, on my older, "orphan" stuff like IH trucks. Clutch forks can get tweaked too and not engage/disengage correctly. If it's a hydraulic clutch actuation I always replace those parts but they generally wouldn't cause partial engagement.

[Spork]

1981 Chevy, in-line 2.5L 6cyl.  Mechanical clutch.  I didn't replace the forks (and didn't even think about that.)   I did the standard: pilot bearing/throw out bearing/pressure plate/disc replacement from this kit.

I don't feel any slip post install... there was a ton with the previous clutch.  Since this is an occasional driver... I pushed it pretty much to the limit on how long I let it go before replacing.

There is also the chance of mechanic error on my part.... but to the best of my knowledge it was done right.  (It's the things I don't know that will bite me though.)

[BlueMR2]

Check (carefully) to see what's hot.  Check the transmission casing after you've eliminated the brakes (hub will be hot if they're the culprit).  I've had many a stuck caliper requiring a rebuild (or even replacement) that has happened unexpectedly in my life, never a clutch issue...

[Forcus]

Since it's AC Delco I'd think it's a pretty safe bet that it's probably correct.

I didn't talk about mechanical linkages since well no one I know except myself has anything with one. But is it possible you tweaked it when you took everything apart? Sometimes they are adjustable and maybe it needs adjusted with a new clutch and pressure plate. But if it's not slipping then it isn't partially engaged and so therefore I don't know what it would be.

Like BlueMR2 said, maybe brakes? If you barely use it. I've had problems with older vehicles, (1) moisture in the brake fluid and (2) swollen rubber brake lines causing problems.

[Spork]

Since it's AC Delco I'd think it's a pretty safe bet that it's probably correct.

I didn't talk about mechanical linkages since well no one I know except myself has anything with one. But is it possible you tweaked it when you took everything apart? Sometimes they are adjustable and maybe it needs adjusted with a new clutch and pressure plate. But if it's not slipping then it isn't partially engaged and so therefore I don't know what it would be.

Like BlueMR2 said, maybe brakes? If you barely use it. I've had problems with older vehicles, (1) moisture in the brake fluid and (2) swollen rubber brake lines causing problems.

I'll fish for hot surfaces this weekend (weather permitting).   I'm reasonably confident in the mechanical linkage.  It is adjustable, but the adjust procedure is very straightforward.  (Adjust length of linkage to fit exactly to one hole... then move the end to another hole and it's set.)

I'm still hoping it's just break in.  If so... it will probably stink a year before I put enough miles on it.  It's not a very fun truck to drive.  No heat.  No AC.  Most of dash and associated wiring are disintegrated.  But for the price I paid for it and what I use it for: it's an optimal vehicle. 

[guitar_stitch]

If it's not slipping in higher gears at low speed, it's not the clutch.  The only way the friction plate can burn is if there is slipping.

As for new clutch smell, I have never noticed any smell on a new plate.