Engine rattle

[Tonyx]

I need to bounce this one off of the experts here.
I have 99 AEG which has rattle coming from passenger side of engine. It's very specific to engine speed, right around 2000rpm. I don't hear it above or below that regardless of load on the engine.

If I was pressed, I would say it sounded like hard belt slap against sheetmetal but don't let that steer your thinking, it's just description of the sound.

I took pictures of back of pass-side engine mount to see if the engine block tab was broken off. It wasn't. The timing belt looks good but I don't have history on it.

Car is running well, around 30mpg combined. Has 145K miles. Your thoughts? The rattle is quite loud and at 25mph or 45mph, it cruises with the rattle so I'd like to take care of it.

[savethebluths.org]

Originally Posted by Tonyx

I need to bounce this one off of the experts here.
I have 99 AEG which has rattle coming from passenger side of engine. It's very specific to engine speed, right around 2000rpm. I don't hear it above or below that regardless of load on the engine.

If I was pressed, I would say it sounded like hard belt slap against sheetmetal but don't let that steer your thinking, it's just description of the sound.

I took pictures of back of pass-side engine mount to see if the engine block tab was broken off. It wasn't. The timing belt looks good but I don't have history on it.

Car is running well, around 30mpg combined. Has 145K miles. Your thoughts? The rattle is quite loud and at 25mph or 45mph, it cruises with the rattle so I'd like to take care of it.

When is the last time you changed your timing belt? Anything look off with the engine mount?

[Tonyx]

I got the car just a few months ago, didn't put 500 miles since(not my daily driver). I don't have history on the belt but with top cover off, it looked spotless - no cracks, no rust spots, no discoloration.

Can't say I saw anything wrong with engine mount. I took a look on the back side just to make sure I didn't need the Van Goh mount fixer. The engine block tab was intact.

[savethebluths.org]

Originally Posted by Tonyx

I got the car just a few months ago, didn't put 500 miles since(not my daily driver). I don't have history on the belt but with top cover off, it looked spotless - no cracks, no rust spots, no discoloration.

Can't say I saw anything wrong with engine mount. I took a look on the back side just to make sure I didn't need the Van Goh mount fixer. The engine block tab was intact.

Well besides those I would reccomend maybe you have someone rev the car while you stick your head in there to check and see whats going wrong, could be anything from a vac leak to a belt going bye bye.

[Droid]

if its an audible rattle bad enough to annoy you while driving...its not the engine mount or timing belt...its the catalytic converter going bad..they rattle like hell when they go out.

[Tonyx]

Update: I took the plunge and ordered the timing belt kit. Replaced timing belt, tensioner, accessory belt, thermostat. Tried to replace the water pump but the one in kit did not fit - impellar grounded out internally when it was tightened down.

The rattle is gone. Orignal timing belt width was 22mm(service limit from Bentley) new belt is 23.5mm. Can't say 100% the belt was the reason for rattle but I have peace of mind knowing I'm good for next 60k miles or so.

Lessons learned:
* have heavy duty jack(not cheap ones where you have to remove handle to control valve) that you can move the engine up/down easily during engine mount removal/install
* have a helper operate the jack while you jockey the engine mount. It pulls out to bottom and installs from bottom
* 16mm standard lengh socket is a must, my deep well 6pt was too long to fit 2 of 3 engine mount bolts
* take out the alternator to replace thermostat, have crow bar handy to persuade the alternator out - easy
* while you have the alternator out, check the bolts that hold the alternator bracket to engine block. They are allen head bolts that may need tightening
* 5mm allen head bolts for crankshaft pulley may strip. Have Torx bit ready as it grips the inside hex better
* you don't need special timing belt tensioner tool as it doesn't take a lot of force to rotate the tensioner. Any curved needle nose plier will do
* after reassembly, plan on flushing 4 times to get all old coolant out of system. Don't forget to run the heater to flush the coolant out of heater core as well. The system capacity is 5.2 quarts so you need 2.6 bottle of G12 after the last flush. I would pour the two bottles(2x1.5L) in the timing belt kit and call it a day.

It took me better part of the day going slow and borrowing the 16mm socket from neighbor. It can be done by person with average skills and good amount of patience.

[simonsi]

Originally Posted by Tonyx

Orignal timing belt width was 22mm(service limit from Bentley) new belt is 23.5mm.

Any belt I have seen that has lost width has done it real quick and then failed. Service life should NOT result in the belt narrowing. If you put on a 22mm belt it should still be 22mm when replaced.

In other words don't be mislead and certainly don't interpret a belt width of greater than 22mm as "ok", it depends on the width as new - and that may differ between supplier...

[savethebluths.org]

Good to hear your rattle is gone, what was the state of the old water pump? Those are usually the most important change other than the TB.

[Tonyx]

Condition of the old water pump was fine. There were no leaks and the impeller was metal type. It spun with some resistance - would not free wheel. It felt the same as the new pump when spun in hand.

The issue with the new pump was the impeller was a few mm's too long. When the three bolts were tightened down it grounded against the engine internally and will not spin. It's good thing I checked before putting the timing belt back on.

I wonder how many times the new pump was put on and the first time engine started it machined itself to fit. Not to mention the wear and tear on the new belt.

The old belt width was 22mm on engine, 22.7mm off engine. So the belt does stretch. I expect the new belt to measure 22.8mm on engine if I measured it.

[savethebluths.org]

Originally Posted by Tonyx

Condition of the old water pump was fine. There were no leaks and the impeller was metal type. It spun with some resistance - would not free wheel. It felt the same as the new pump when spun in hand.

The issue with the new pump was the impeller was a few mm's too long. When the three bolts were tightened down it grounded against the engine internally and will not spin. It's good thing I checked before putting the timing belt back on.

I wonder how many times the new pump was put on and the first time engine started it machined itself to fit. Not to mention the wear and tear on the new belt.

The old belt width was 22mm on engine, 22.7mm off engine. So the belt does stretch. I expect the new belt to measure 22.8mm on engine if I measured it.

Ok that's great, it also means the belt was likely changed before you got it.

I think you're in the clear so happy driving!