Possible clutch going out?

[924Sman]

Lately I have been getting a smell of something burning. My best guess it is clutch disc material. Not oil for certain, this had a very distinctive odor. This AM I fired the car up and sat for a moment and started to actually see the bluish smoke coming from under the car but cannot tell where it originates from. The clutch seems to work ok no slippage or any other odd symptom. My best idea is the clutch is on its way out.

Anyone have a clutch go out with the first symptom being the smoke and odor? Or might I be dealing with something else? But for sure the smell is fibrous in nature.

87 924s

Thnx!

[mytrplseven]

If the clutch is not depressed after you start it up and the clutch is performing ok, I'd be reluctant to say it's the clutch. The best method to verify the clutch is jack it up on the driver's side and do the inspections for wear limit and put your finger in the inspection hole to see if there's pieces of rubber (assuming you have a rubber centered clutch plate) in the hole. Haynes manual and Clark's Garage both have the info on this inspection. Barring anything else, I'd do a couple of speed shifts from 1st to 3rd to see, under heavy throttle, if there's slippage in the clutch under full power.
Do you hear any new exhaust noise from under the passenger seat area? Might want to look under the car with a flashlight (to highlite the smoke) to see where the smoke's originating from.

[924Sman]

Not rubber disc I don't think. It was replaced several years ago by PO and best guess from records it is spring centered. I thought to look at the inspection hole but was not sure that would tell me much, I will have a look. Only issue on shifting is it will grind going into second if I do not time the throttle correctly, meaning allowing the RPM's to drop a bit lower. I htink this issue is a driver related one but never happen until recently. But hi speed shifting has been flawless so far.

Exhaust was my second area but I have no cat and a modified testpipe in its place, but I do have some muffler tape in and around the area, I will give this a look.

Thnx!

[John_AZ]

Originally Posted by 924Sman

Lately I have been getting a smell of something burning. My best guess it is clutch disc material. Not oil for certain, this had a very distinctive odor.


This AM I fired the car up and sat for a moment and started to actually see the bluish smoke coming from under the car but cannot tell where it originates from.


87 924s

Thnx!

Tail pipe smoke colors:

White-Usually Coolant
Black/grey-Usually rich fuel mixture
Blue-Oil burn

You may have a bad exhaust manifold or flange gasket.

????

J_AZ

[924Sman]

I have the smoke colors down but no smoke out of the tail pipe for sure, this is coming from around the starter best I can tell. I know I have a leaking oil pan gasket but never bad enough to hit the headers etc. This is a get under the car and look around sort of thing no doubt. I am just puzzled by the smell, it really smells of asbestos or fiber of some sort.

Thnx John

Dal

[VirginiaF1]

Originally Posted by 924Sman

I have the smoke colors down but no smoke out of the tail pipe for sure, this is coming from around the starter best I can tell. I know I have a leaking oil pan gasket but never bad enough to hit the headers etc. This is a get under the car and look around sort of thing no doubt. I am just puzzled by the smell, it really smells of asbestos or fiber of some sort.

Thnx John

Dal

Howdy..
I realize its only been a few hours from your opening post so perhaps not time yet for ya to view the clutch port. I wonder:

1. How many miles on this clutch?

2. When was/what'd you see the last time you viewed the clutch port window?
(From 18mm to 34mm slave cylinder life travel)

3. Could that acrid smell be the starter motor staying slightly engaged & slowly burning up?

4. Oxygen sensor newish?

5. If it indeed turns out to be oil burn, any ZDDP additives that may be changing smell?
(I used Rislone ZDDP once and the oil smoke at mt exhaust flange leaks smelled putrid.

Cheers
mikey

[924Sman]

Correct have not had time to get a look yet.

1: I would hazard a guess around 60K or more

2: This has been awhile so I have no clue, know once I get in and look/measure

3: Doubt it, no electrical smell at all

4: No additives at all

Thnx
Dal

[mytrplseven]

One of the things I heard about is that the Sachs conventional clutch plate doesn't last as long a we think it will. It was recommended on one post to buy an Italian manufacturered disc instead. I guess I assumed that you might have a rubber centered clutch. With the mileage and the other symptoms you described, you may well have a disc that pretty much on it's last legs. I'd still do the min/max wear check in the inspection hole to get a real handle on how much it's worn.

[924Sman]

Update: Finally able to get a look and the best measurement of the slave piston is around 24mm +/- 1.5mm....I did see some light coating of oil around the section just in front of the flywheel, this oil appears to be engine oil. I did have some oil on my headers as well so this may be the issue. The car has sat most the year and forgot I have winter oil still in and the little bit I have driven it this summer with the 5w30w imho is just too thin thus the known oil leak I have has just benn magnified by this thinner oil cascading further away and around the engine/exhaust.

Hope this makes sense

Dal

[VirginiaF1]

Originally Posted by 924Sman

Update: Finally able to get a look and the best measurement of the slave piston is around 24mm +/- 1.5mm....I did see some light coating of oil around the section just in front of the flywheel, this oil appears to be engine oil. I did have some oil on my headers as well so this may be the issue. The car has sat most the year and forgot I have winter oil still in and the little bit I have driven it this summer with the 5w30w imho is just too thin thus the known oil leak I have has just been magnified by this thinner oil cascading further away and around the engine/exhaust.

So the clutch life is at 33% Used?
(ie: Slave Cylinder Travel: 18mm start, 36mm end; and thus 24mm is 6mm or 33% of travel left to right from 18 to 36)

Thinner oil leaking/permeating rearward into the bell housing would be a perfect explanation of your particular odor issues, ya?

[Slam]

How's your cork gasket?

[924Sman]

Originally Posted by Slam

How's your cork gasket?

If you mean the gasket on the rear cam tower it is good.

[924Sman]

Originally Posted by VirginiaF1

So the clutch life is at 33% Used?
(ie: Slave Cylinder Travel: 18mm start, 36mm end; and thus 24mm is 6mm or 33% of travel left to right from 18 to 36)

Thinner oil leaking/permeating rearward into the bell housing would be a perfect explanation of your particular odor issues, ya?

Well it could be the odor but in my experience oil does not smell anything close to what I smell, not saying it is not the oil just rather odd smell for oil burning, but it does however explain the color.

I wonder if any chance oil can get onto the disc plate? Maybe a rear seal?

[John_AZ]

A random "carnival ring toss guess" --usually a miss.

The heater control valve above the clutch bell housing.
If there is a leak in the valve, hoses or clamps, the coolant will drop on the clutch and ruin it.
A white deposit on the valve usually shows a leak.

J_AZ

[924Sman]

Something to consider. But never knew there was such an animal in that location. Is it easy to get to?

[John_AZ]

Follow the fat heater hoses on the drivers side to about center---then check the heater control valve for white deposits like this:



Easy to get to -----DO NOT loose the control cable clip if removed.

J_AZ