Strange noise at the front of my '96 355 engine.

When I first start the car, while its still cold, a sort of hollow somewhat "rattle" like sound comes from the front of the engine. Not tinny, more deep and hollow. Not loud either. You have to listen for it but its definitely there, at least for a short while (minute or so). But, after it warms up, it more or less goes away. Even revving the engine doesn't bring it back. All sounds normal. When I hear it, it seems to be the same on both sides of the engine. It doesn't seem to favor either side.

The belts with new Hill tensioners were installed less than 1200 miles ago with the last major so I don't think its coming from them. I also just replaced my AC compressor from Ricambi about a month ago so its not likely this either. That leaves the alternator, water pump and power steering pump as other possible culprits. Since it doesn't seem to favor the passenger's side, I'm not ready to look at the alternator That leaves the power steering and water pump. I've never heard a water pump going out on a 355 before so I have no experience with that kind of sound but this is what I'm most suspicious of at this point (although I can't rule out the power steering pump).

Questions: If its the water pump, can it be replaced without pulling the engine? Does this sound like a water pump to you guys? If not, short of the power steering, what else could it be. Could this possibly be something more or less normal before warming up?

By the way, the engine/oil temperatures hold just like they should whether driving or idling, at least so far. The electric fans work as they should too so water must be circulating properly or it wouldn't behave like this.

Ideas??????

 

May be the Hydraulic tensioners, were they replaced also? Or belts were adjusted too loose.

Hope not

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That is a nice looking tensioner.
Where did you get it??

 

New OEM

 

Should i be scared of the cost??

 

Yes, you should be scared

 

As for the noise, you have to lie underneath the car with a stethoscope. Most likely the alternator tensioner bearing if it is from front of the engine. Water pump leaks before it makes noise.

 

SoCal1,

I don't know if the hydraulic tensioners were replaced or not. The major was done just before I bought the car. Are these different than the belt tensioners that I know were replaced with the Hill units? If this is the problem and these are going bad, what are the consequences? Would both sides be going bad at the same time? Since the noise stops after warm up, as long as it continues this way, is it safe to continue to drive it? I suppose these can't be replaced with the engine in the car, correct?

yelcab,

I forgot about the alternator tensioner. If not the above, that could be it. If so, what are the consequences driving it since it seems to go away after warm up? Can it be replaced with the engine in the car?

Appreciate your help guys. Thank goodness for Fchat!

Jerry

 

You need to remove the engine to replace the water pump

 

No you don't

 

My suggestion is to bring back to shop which did AC compressor change and inform them noise started after job. Don't necessarily blame just ask to diagnose by stacting car and raising on lift to better pin point the noise. You might find something wasn't fully tightened back or someone's tool left - just kidding

 

Another vote for alternator belt tension. When cold, it puts more stress on the pulley and produces a rattle. Once warmed up, all is good. I actually would not worry about it as long as the symptoms do not change. This is my opinion.

 

Thanks Challenge. Nice to know. This reassures me a little. I don't think (at least I hope) its not the tensioners as mentioned by SoCal1. The shop and previous owner were pretty knowledgeable and thorough when they did the major (among several other things, it included a complete head rebuild). If this were a possibility, I believe they would have addressed it then (again, at least I hope so).

If the noise gets worse and I find out for sure its the alternator belt tension, can it be replaced with the engine in the car? Do you know if Hill Engineering (or anyone else reputable) makes a better replacement as opposed to buying OEM?

 

AFAIK, hydraulic tensioners are only available via OEM

 

Doable, 1 hr with engine in car and a lift.

 

Dave, What about the alternator belt tensioner? Does anyone make a replacement to improve on the OEM like Hill does with the cam belts?

 

No, but it is a static tensioner and all you need to do is to replace the BEARING which you can get for $25. Tension the belt manually until it meets a certain tight enough spec, and leave it alone.

 

Well, IIRC, it's an JAF bearing and I don't think it's anything special.

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355, don't know it well... get it on a lift as others have said. Remove alt & AC, power steering belts, maybe 1 at a time if nothing obvious beforehand.... process of elimination!

 

Yes -- the piece that Mitchell has shown is the actual hydraulic tensioner -- there is one on each side of the engine (https://www.ricambiamerica.com/157356-hydraulic-tightener.html). The Hill Engineering units are tensioner bearings (https://www.ricambiamerica.com/pt355-355-cambelt-tensioner-bearing-pair.html)

The sound you describe could be a failure of the alternator bearing. It's a relatively small and commensurately crappy bearing which may have slung out its grease and makes noise until whatever's left inside of it warms up sufficiently. https://www.ricambiamerica.com/172537-plastic-pulley.html NOTE: early cars before assembly 28600 use a replaceable bearing that is pressed into an aluminum pulley -- unlike the linked 'plastic' one above. If yours has such a design, the bearing is an individual component here: https://www.ricambiamerica.com/123350-bearing.html

 

Daniel,

You mean "Tim", not "Mitchell"

 

Our cars are getting 20 years old, mine looked fine last 10 years but even if they look fine now and work properly how does a guy know if we should be replacing them.

I tested by pishing in and out, they were nice and clean, etc. Any suggestions or things to look at?

 

Thanks Daniel. What about the alternator belt tensioner? Does Hill make a replacement for this?

 

Dave/yelcab, I didn't understand this at first. My bad. If it turns out to be the alternator belt tensioner then all I need is a new bearing. If so, where's the best place to get one?

 

I replaced mine with a standard piece, SKF or NGK I believe it was. The dimensions are common, so there are more brands that produce this bearing.
If you can't find the dimensions, let me know, I have kept the parts from my major somewhere, so I should still have that old bearing..