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I recently snapped my timing belt. Was planning on replacing it this fall or next spring. Thought it was at 3 years since I did it last time. Looking through previous threads, it was actually 4 years. Unfortunate to have it snap at 4 years and about 8k miles ago, but I can at least be a cautionary tale.
I am in the process of getting it apart to find out what damage has been done. I don't have a lot of time to work on it, so this will likely be a slow progress thread. Currently I have done the following:
Disconnected Battery.
Removed starter.
Set to TDC using mark on flywheel.
Removed timing belt covers.
Removed fuel rail.
Removed all belts.
Removed Intake.
Removed camshaft cover.
Removed Distributor.
Next I plan to pressurize the coolant system and inspect all of the hoses looking for small leaks. I have lost a little coolant over time. I then plan to get the head removed so I can inspect what damage has occurred.
When the timing belt snapped, I had just rounded a turn and was starting to accelerate slowly, so low speed and low rpm's. I coasted to the side of the road and attempted to start and it sounded like no compression so I feared the worst and called a tow truck to get me home.
Adding some images. I don't see anything that caused the failure but would appreciate some additional eyes to help me make sure I don't need to change anything else.
When I did the belt job in 2011, I also replaced the WP, rollers and did a FOES job with the exception of the camshaft seal.
Thanks in advance for any input.
First Pic. Have part of the cover off. This is what I first saw.
Some oil by the camshaft.
Snapped Belt..... Need to work on my focus.
Back side of the belt.
Markings from the belt I installed. I want to verify the brand before I put anything on the forum.
Inside of the timing belt cover appears to have some rubber shavings gathered in a couple of areas.
Sorry to hear, that really sucks. Get the head off and inspect the valves. Was it re-tensioned after the last install? If there are no broken rollers or bolts and water pump is not rubbing or seized then maybe tension was loose. Possibly deceleration created slack and rollers or cam skipped teeth horribly.
Have you confirmed that the cam turns in its housing? (And that the motor turns over?) Seems like it would take a lot of force to snap a belt apart like that...?
I'd suggest that the water pump seized up when the engine got hot enough, then frees up after the engine cools down. I've heard of bearings doing that before.
The cam turns very freely. No issues there. All the little "beer cans" as my wife calls them go up and down without any hesitation or catch.
Turning the crank to get the engine to TDC was very easy without compression. I made 1 full revolution i think.
I doubt it was anything with the water pump getting hot. I was about 1/2 mile from home on a nice cool morning and the car never has run hot. Usually at operating temp, it get to the bottom white bar.
Do I need to turn the crankshaft over a couple of times to see if I feel anything?
I'm actually halfway through replacing the water-pump and timing/balance belts myself. I just bought the car in July, and was terrified to find out the water pump and belts were replaced 10 years ago (or 20,000 miles). Luckily I'm doing the work in time (belts look fine, water pump was leaking slowly though).
Based on the photos and age of the belts, I have to agree that the water-pump seized and cooked the belt.
The melted 'rubber' stuck to the water-pump pulley seems like solid evidence. The backside of the timing belt also looks quite distressed.
Do you recall if the water-pump was new or rebuilt?
The water pump was rebuilt and purchased from one of the reputable sponsors of this site.
Since I see some rubber dust inside the cover in many places, I think the rubber on the back of the water pump in some shavings that have been caught by the belt and built up over time as it was turning. The rubber build up easily scratches off with a fingernail and goes around the full circumference. It doesn't appear clean in one area suggesting a belt rubbing against it and knocking off some of the buildup, or dirty in one area suggesting belt rub in a specific area and burning rubber off like you might see if the water pump seized.
I am not saying it isn't the water pump at this point, but I am skeptical. Would like some more opinions.
There's no way this is related to time (4 years vs. 3). The modern Gates and Contitech belts are extremely robust and are good for a lot more than 3 years or 8k miles. I know that a lot of folks like to change them at 3 years, but IMO that is extremely conservative. Either something is seized or the belt tension was way off. There's no way that a non-defective Gates or Contitech belt would just snap because it's 4 years old. The fact that there are belt shavings around should be a clue as to the root cause -- that is not normal at all. The rubber on the waterpump pulley is also not normal, although the explanation that it is deposited shavings is viable.
Any chance that your lost coolant could have been leaking from the water pump area? If any coolant was routinely getting on the belt then it may have contributed to premature failure.
I think I have evidence that something seized up somewhere. Inspecting the belt, it looks like the ribs are perfect until about 6 inches before the break where they seem to be cracking on one side.
Here is about 8 inches before the break.
As you get closer to the break, you see cracks starting to develop.
At the break, you see it getting progressively worse.
09-21-2015, 05:47 PM
Broken Timing Belt
Need to work on my focus.
