metallic rattling noise from engine bay? - Toyota Nation Forum : Toyota Car and Truck Forums

BugDiddy · 05-30-2009, 06:36 PM

hey guys I have a 4afe and recently it began to produce a rattling noise from the engine bay.. it sounds like if you jingle a chain in your hands.

i think it is related to engine rpm/load because it doesnt happen at warm idle mostly when accelerating.

I have a feeling a pulleys bearings have gone out, but how to i narrow down my search? since the sound changes with engine load, i was thinking it may be an idler/tensioner pulley for the timing belt.

any ideas??

tashirosgt · 05-30-2009, 09:06 PM

If you can get it to happen when the car is out of gear, take a broom handle or a pipe and use it like stethoscope. I'd check for the worst possibilities first, that would be noise from the block or the head. The next worse would be the crankshaft pulley and timing belt tensioner. It would be hard to listen to those so you should take of the timing belt cover and inspect them . How many miles since you changed your timing belt? Other possibilities - loose idler pulley, bad water pump, bad AC compressor.

If you can't get it to happen with the car out of gear, check your suspension. I suppose bad CV joints can made various types of noises.

BugDiddy · 05-30-2009, 10:15 PM

Ugh.. God I hope it's nothing serious.. I am hoping it's the idler or tensioner because I sure can't afford a rebuild right now..

When I first got the car, there was no cover on the belt so that's why i'm thinking a timing pulley. I should replace the belt too since I don't know when it was done last. Is that job fairly straightforward?

tashirosgt · 05-30-2009, 11:03 PM

I would not say that replacing a timing belt is straightforward since you either have to keep the camshaft gear and the crankshaft gear in the proper relation or restore that relation if it gets disturbed in the process. If you are comfortable with that and with releasing the engine from one mount and jacking it up a little then you can do it. I've done it, but I did it at a leisurely pace. ( I advise that you use an impact wrench to take of the crankshaft pulley. It's one of the few places that I would not use a hand tool.) You need to get a service manual before you attempt this job.

It isn't a good thing to be missing the timing belt cover, You don't want to get grit on the belt and make it wear faster. The timing belt cover has three sections. Are you missing all three? Or only the top one?

Anyway, listen to the head and block first.

BugDiddy · 05-30-2009, 11:56 PM

Yeah I'll take a listen tomorrow. I've done timing belts (3sfe and a d16a1) before but just not with my own supply of tools. It was missing the top pieceof the cover but I replaced it right when I bought the car. Either way the belt needs to get changed.. Just a matter of whether it's the culprit of the noise I'm hearing.

TonkaTom · 05-31-2009, 12:36 AM

If it only happens at certain RPM's then check to make sure all of your engine mounts have all of the bolts that they need. (Mines makes a noise when decelerating because of this.)

90 GP · 05-31-2009, 06:29 AM

Sounds like you have a case of pinging. Check for vac hose leaks, clean carbon from engine (Seafoam) or try using a higher octane gas.

boopie · 05-31-2009, 10:21 AM

I was bored one day and read the owners manual and it read that pinging noise and knocking during acceleration was normal. Check it out if you don't believe me. It was near the octane recommendations part.

aHarmony · 05-31-2009, 11:15 AM

This may be a long shot, but do you think it could be your exhaust manifold heat shield? Many of the bolts holding them down come loose from heat and metal expansion or just rust out...even if it's a bit loose it will rattle like hell and change when you accelerate of course.

BugDiddy · 05-31-2009, 12:37 PM

ok so i took a listen, and it really sounds like its coming from the distributor side of the engine. I made a video... maybe it will help, maybe not:

http://www.youtube.com/watch?v=42oOYM4zatM

I took off the heatshield to see if that was the problem- still has the sound

Also put in about 4 gallons of 93 octane to see if it had some bad gas- still has the sound

90 GP · 05-31-2009, 02:23 PM

That sounds like a clamp rattling on the exhaust pipe. Check the front pipe in the area of the braided flex part to see if something is broken off and rattling.

BugDiddy · 05-31-2009, 06:00 PM

ok well I took your advice and climbed under the car... found 2 new possibilities

-front motor mount is shot. are all 4af/e/all-trac mounts interchangable? junkyard time :-D
-a bolt is missing from a bracket connected to the exhaust

pictures:

That exhaust bracket seems like it would be most likely- though I'm not sure how the bolt would come out. as far as i can tell the bolt isnt broken off, its just missing. maybe the bad motor mount helped

oh well this gives me an excuse to go to the junkyard

90 GP · 06-01-2009, 04:25 AM

Looks like there is a heat shield above where the missing bolt on exhaust mount is that could also produce the noise.

retiredat44 · 06-01-2009, 02:56 PM

A water pump that is going bad can rattle like hell too.. but since you siad it's on the other end of the engine, than it is probably not that,, a clutch can rattle if a certain type of clutch bearing is used and goes bad...... there are too many parts to guess about this rattle though..

boopie · 06-05-2009, 06:19 PM

Thats how my motor mount looked too. I didn't know it was bad till I had the clutch replaced. It cost like $50 to get a new one. I wouldn't rely on a junkyard mount. I guess it couldn't stand the heat since its under the radiator and close to the header.