355 Horrible rattle at tickover any ideas?

Hi

Not a major issue (I dont think) but started car yesterday and something was rattling to the front left of the engine - sounded horrible like squeeking metallic vibration which was rythmic with the cams rotating at a guess. At first I thought the worse then listening past the sound increased the revs by 100rpm and it vanished. Once a little bit of heat got into it everything was fine and went for a drive - no issues.

Just wondered if there is a known issue, I washed it recently and may have lost a blob of grease from somewhere (low pressure wash). Or maybe something has come slightly loose in the engine bay infront of the block?

Car has been sitting idle over the winter, although I periodically start the engine - this has appeared since I last washed it though. Sound not coming from the water pump or alternator - guessing more like power steering pump...

Any ideas?

 

Richard if ya need a second opinion being that i live down the road in Derby. I can call up to see you tomorrow morn (wed). I can have a listen and tell you what i think it is.
Could be that the water has got into the front pulley of the power steering pump or air con pump. The alternator is on the right hand side of the engine anyways. Or it could be the auxiliary bearing at the bottom centre of the engine. Lets not even talk about cam belt bearings
MB: Maybe you should give it a good run to rid it of any water that may be at the front.

 

Well since you got the engine wet, I would start by disconnecting all of the electrical connections hit them with WD40 and drying them out with some compressed air, to help get rid of the rest of the water.

As for the tapping noise, it could be a few of things. It may be your header giving out, or one of the bearings for the a/c tensioner, or worse a bearing for the cam belt. You are really gonna have to isolate exactly where the noise is coming from.

 

Or maybe the exhaust by pass valve opening and closing

 

I would want to be absolutely sure what made that noise and correct it before ever driving off somewhere. Just because a noise stops does not mean what caused it has mysteriously fixed itself. Machines never fix themselves, its just a constant downward spiral of wear and decay, with short periods of attempts at reversing it.

I would have immediately shut it off and solved the issue before running it any more, much less taking it out for a spin.

 

The car would have to be started again for diagnosis. One cant just pull the engine to get at the front of the engine with out at least knowing were the sound is coming from. Unless one has money to throw away.
Machines dont fix them self ya right, but water in bearings and pulleys do.

 

I know and so would I, but it didnt sound like a "shut down kind of noise" - but I listened very carefully and checked for the obvious - it was loud and rattling, 90% certain it was caused by movement of the engine vibrating something round the front of the engine. There was no bearing whine at all - the engine itself sounds fine and its not exhaust. Increasing revs (very) slightly cured it which is why I went for a drive - it was the change in resonance that cured it hence some kind of movement. I think water has got somewhere as chaa suggests - thanks for the offer m8y, if it re-occurs I may take you up on it.

Thanks for the quick response guys, I'll post back when/if I discover what the little critter is. Maybe do a recording.

 

Just started it, sounds fine now. I bet its those damn standard cats and silencer - as soon as you make the engine "quiet" you hear all sorts of things...I need to change my engine lid struts - just banged me on the head - I'll have a poke around then.

It may have been some gravel caught between the engine and bulkhead (got a gravel drive), it was loud and rattled a lot.

I do recall some odd noises from the power steering at tight lock whilst driving, only feint ones so maybe its down there somewhere.

Thanks guys - you know what its like - its good to talk

 

Does the 355 have cast alloy cam belt covers? or has it switched to modern plastic ones.

My 308 cracked one of the cam belt covers near to a bolting point. It made the most auwful noise due to sympathetic vibration - admittedly at higher revs. From inside the car it sounded like one of the camshafts was on the way out. Initially it was more than 5,000 revs, then it moved down the rev band to >4,500, then >4,000 revs as the crack ran. Lower revs, no noise from it whatsoever.

So it could be something like that, a loose bracket, something touching against another thing, or such like. Try a touching things with a stickand see if you can stop the noise.

For £5 you can get a mechanic's stethoscope, which has a long probe and make the job of finding a particular noise source VERY MUCH easier:

http://www.machinemart.co.uk/shop/search/filter/stethoscope/page/1


Nasty noises aren't always nasty?


David

 

Thanks David, if it returns I'll go for a probe - covers are plastic I think.

 

For £5 you can get a mechanic's stethoscope, which has a long probe and makes the job of finding a particular noise source VERY MUCH easier:

Amen to this suggestion. I have had great luck by using such a stethoscope. It is a cheap and effective way to isolate the source of the noise. I have a friend who had an ancient v8 pickup that rattled when first started but the heavy noise would go away when warmed up and revved up. His mechanic was ready to pull the engine and replace rod and main bearings. I had him start it up on a cold evening, used my stethoscope and found the source of the noise, a gas line thumping against the valve cover while the choke was still on and the engine was rocking back and forth.
Ed

 

Richard, Your noise sounds and behaves similar to mine.

I fitted two new accessory drive belts, removed and checked the altenator, removed and checked the alt belt tensioner and bearing and all looked OK. I checked the a/c compressor clutch and it seemed OK but my noise is still there slightly at start up and low RPM.

I should have started the car up with the a/c compressor belt removed because I still suspect the a/c clutch.

Will get one of those stethoscopes tomorrow, looks like a good buy at £6.

 

My noise gone away now although I think I hear it a little now and again at tick over.

 

Well my noise, with a similar sound to Richards is still there at around 1500-1750 rpm. Pass through that range quickly and no noise, build up rpm slowly and its there, hold it at that rpm and its persists.

It gets quieter with the engine hot. It seems with a certain vibration level the noise appears.

My thoughts are towards cam belt tensioner/s or even perhaps a water pump, either way no choice but to pull the engine if that is the case.

Anyone have any other ideas?

Thanks in advance for any help.

 

Terry, take the altenator belt off and run the engine, if the noise is still there do the same with the AC belt.If it's still there at least you have eliminated some possibilties.

 

Have you checked your oil level? Oil pressure OK?

 

Thanks Steve, I do need to do that. I have had the altenator and alt belt tensioner off (when I changed the belt) to check and they appeared fine. I also checked the a/c comp clutch and that too seemed fine. Hard to reach the w/p though.

But like you say, to be sure I need to run the engine with both belts off.

 

Thanks Matt, oil level is good (new oil also - Mobil 1 0-40) and the pressure is fine.

 

Well I removed the a/c belt and the noise was still there.

I then slackened off the alt/water pump belt but the belt was slipping because it wasn't slack enough. I removed the alt/water pump tensioner pulley and then the belt was nice and loose.

I started the engine again (only for a minute or two) and was trying to see if the noise was still there and something seemed to go "pop" and the engine was then very smooth. I then shut the engine off to see what was happening.

I looked at the water pump pulley and saw the belt was still in the groove but resting against the pulley was the top of the heat shield between the engine and fuel tank. It was not hooked under the retaining nut and was therefore loose to rattle against the pulley, see picture.

I thought this must be the problem so wanted to start the engine again to proove it but now the starter motor turns but does not turn over the engine.

I wonder if the "pop" I heard was something going on? I wonder if by co-incidence the starter is now a problem. I had the starter out a week ago and fixed a bad plunger on the solenoid and gave it a look over and it seemed fine.

I have now put the battery on charge. Perhaps it was a little low and running the engine with the alt belt off has discharged it too much (volts on multimeter were 12.63V)

You hear the sm turning but does not seem to turn the engine, any ideas?
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Two events attached to the same system would tend to point in the direction of the starter. Perhaps the noise was the heat shield, and somehow its related to R&Ring the starter? Perhaps when the shield popped it cut or pulled a wire loose at the solenoid and made your starter inop?