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Knocking sound in timing belt?

Tiny
JEREMILORENTI
  • MEMBER
  • 1997 VOLKSWAGEN JETTA
  • 81,000 MILES
So the other day I went to start my 1997 Jetta GLS 2.0, and it didn't want to turn over, but finally did, only to have it stall one second later, and have a puff of white smoke come from my engine. When I looked, the timing belt had snapped off. With this car it has a dual V belt setup. The thicker belt had snapped off. (The one on the crank, alternator, and ac compressor).

I went to try and start the car again, and it started right up, perfectly. Sound clean, and drove smooth.

I bought a new timing belt and put it on, and now the car struggles to start up again, and when it is on, there is a LOUD knocking sound coming from the area of the belt. Also, the car and electronics feel like it has surges or energy. Lights dim, idle goes down, etc.

Keep in mind though, that when the belt was off, the car was fine.

What could this be?
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Wednesday, September 26th, 2012 AT 4:27 PM

21 Replies

Tiny
KHLOW2008
  • MECHANIC
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That is not the timing belt. It is the serpentine belt and symptoms indicates possibly one of the alternator or A/C compressor being seized. Remove the belt and manually turn the alternator and A/C to see which is not turning.
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Wednesday, September 26th, 2012 AT 6:20 PM
Tiny
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Ah I see, my mistake.

When I changed the belt yesterday, I did check to see if the pulleys moved, and the alternator moved freely, but not where it would just spin continuously. The AC pulley however, did not budge with me trying to hand turn it.
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Wednesday, September 26th, 2012 AT 6:46 PM
Tiny
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Might help you to know that prior to changing the belt, there was a lesser knock, but still a loud one.

And my AC never worked, as in it would not blow out cold air.

This leads me to think it is the AC Compressor that is causing this.
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Wednesday, September 26th, 2012 AT 6:50 PM
Tiny
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Also I just checked, the AC pulley does spin when the car is on, but it is very shaky. It pivots a lot.
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Wednesday, September 26th, 2012 AT 7:35 PM
Tiny
KHLOW2008
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You seem to have a bad A/C bearing problem if it waves a lot while turning and is the main cause of the belt shredding/snapping.
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Thursday, September 27th, 2012 AT 5:52 AM
Tiny
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I replaced the AC Compressor with a Bypass pulley and also replaced the alternator.

Now the car has NO knocking sound.

Seems like it's all fixed EXCEPT now the belt squeals LOUD when I accelerate or turn the steering wheel.

I don't believe the belt is loose, as I could not get a 1130 sized belt on but was able to get the next size up, being a 1170 or something around there.

It was a bit difficult to get the belt on even with the tensioner pulled back all the way.

Do you think the belt could be too tight? Would that cause squealing?

Also, when the belt was off, my steering was extremely smooth and easy, but now with the belt, in addition to the squeals, the steering is extremely hard and rough.

What could it be now?
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Thursday, October 4th, 2012 AT 10:13 PM
Tiny
KHLOW2008
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I believe the power steering belt tension is too loose. An oversized belt might not have sufficient tension even if it is adjusted to maximum.

Belts do not slip onto the grooves easily. After getting part of the belt onto the groove, you need to turn the crankshaft to let it slip in.
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Thursday, October 4th, 2012 AT 10:27 PM
Tiny
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Why would the steering be easy when the belt was off?
Wouldn't that mean the powersteering pump wasn't even being powered?
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Thursday, October 4th, 2012 AT 10:28 PM
Tiny
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And I think the belt is tight, personally.

The belt size I tried prior to this one was not long enough and would not go on the pulley, but this one does, but was hard to get on.
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Thursday, October 4th, 2012 AT 10:30 PM
Tiny
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KHLow2008 is talking about the V belt (the one that runs the water
pump & power steering).

http://www.germanautoparts.com/Volkswagen/Jetta/Engine/15/4

You are talking about the serpentine belt that you replaced.

If I am reading things right...

Thomas
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Thursday, October 4th, 2012 AT 10:41 PM
Tiny
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I am talking about the serpentine belt yes.

The V belt is fine, I'm sure.
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Friday, October 5th, 2012 AT 12:30 AM
Tiny
KHLOW2008
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Squealing only when turning the steering indicates the V-belt is the one you should be checking the belt tension.

How did you check the tension?
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Friday, October 5th, 2012 AT 1:02 AM
Tiny
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But I have never had an issue with the V belt.

When the Serp. Belt broke off, my steering was fine and there was no squealing.

Put the new serp belt on and now there's squealing and hard steering.
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Friday, October 5th, 2012 AT 1:04 AM
Tiny
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In order to install the serp belt, you had to remove the v belt.

KHLow2008 wants to know if the belt is tight? Grab the belt at the
bottom between the crank & the p/s pulley and wiggle the belt.

If it is loose, adjust the tension via the p/s pump adjustment.

Thomas
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-1
Friday, October 5th, 2012 AT 1:10 AM
Tiny
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How would I apply tension to the V belt using the p/s pump?

I know how to use the serp. Belt tensioner, but not the V belt.
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Friday, October 5th, 2012 AT 4:23 AM
Tiny
KHLOW2008
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Loosen nut -4- and bolt -1-

Loosen clamping bolt -3- for adjustment bolt -8- at least one full turn 1.

Adjust V-belt tension by turning adjustment bolt -8- with torque wrench - A -

Specifications:

Used belts: 4 N.M (35 in. Lb)

New belts: 7 N.M (62 in. Lb)

Tighten clamping bolt -3- to 25 N.M (18 ft lb).

Tighten hex bolt -1- to 45 N.M (33 ft lb).

Tighten hex bolt -2- and nut 4 to 25 N.M (18 ft lb).
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Friday, October 5th, 2012 AT 4:38 AM
Tiny
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Well I ha encountered another problem.
Last night as I was driving, the car began to overheat.
I pulled over and took a look, and I saw that a hose that goes to the radiator popped off, and I had lost all my coolant.

I was close to home, so I pushed back home, and put the hose back on with a new hose clamp.

I filled her up with water, but now the car sputters when I try to accelerate, o there is just no acceleration at all, and there is what I thought was white smoke, but may be steam coming out of the engine.

I took a look and I see I have another leak (you can see where in the attached picture, near the bottom rear of the engine.)You can even see the (steam?) Pouring out.

Would this leak cause the sputtering.

The temp gauge stays in the middle now, but what is causing the other issue now.
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Friday, October 5th, 2012 AT 3:05 PM
Tiny
KHLOW2008
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Picture does not show exact point of leak and you need to locate the source.

Overheating can cause damage to the head gasket and that can result in engine sputtering. You need to get it diagnosed.
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Friday, October 5th, 2012 AT 3:12 PM
Tiny
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Radiator hoses don't just pop off... they are not only held in place
by a hose clamp, but also a "raised lip" that is molded into the
radiator fitting.

Remove the hose again and check if the end of the radiator fitting
has broken off... this will leave only a "straight" piece on the
radiator that the hose / clamp can clamp to and with enough pressure
the hose will simply slide off.

As for the side of the head, it is usually the plastic coolant flange:

http://www.germanautoparts.com/Volkswagen/Jetta/Cooling/117/11

There is a small coolant hose attached to the side of the cylinder
head... there's some white goo spraying down from it. Check to make
sure that that hose is not split.

Sputtering could be from the coolant / moisture that sprayed onto
your ignition components.

A wet distributor, ignition wires or ignition coil will cause sputtering
and loss of power... this should clear-up as the components dry-out.

Make sure that there is no goo in the coolant reservoir, if there
is, then you might already have some kind of head gasket / oil cooler
problem.

Thomas
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Friday, October 5th, 2012 AT 4:09 PM
Tiny
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I added a P/S belt loosening & tightening video to my youtube channel:

http://www.youtube.com/watch?v=NVPKvza3kSw

Thomas
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Sunday, October 7th, 2012 AT 4:09 AM

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