A strange sound from under the hood!

[jackathy]

Since signing up last year I've read the forum almost daily but haven't contributed much. I have a daily driver Mark II Sprite with a 1275 engine, and have found that the only way to keep it on the road is to do the work yourself. I now regret not taking 9th grade automotive mechanics! But I'm learning (through the forum) and driving the Sprite about a thousand miles a month around western Connceticut. For the most part the engine purrs but recently, starting about 3500 RPM a strange sound begins that sounds like something is loose and sporadically clanging against metal. Almost as if there were a metal tag flapping around. I've been looking for something loose until going down a hill today I put the car in neutral and coasted. The sound stopped. When I got home I lifted the hood and revved the engine to 4000 RPM and the sound seems to be coming from the fan. While the blades are not loose, there is some play in the assembly. Could it be that there is not supposed to be any play there? I couldn't find any reference to this in the books although Glenn mentions a bent and out-of-balance fan as being a cause for accessory noises. It doesn't look bent and how would you tighten it?

Jack
62 Sprite
95 Miata

 

[Dave Russell]

Jack,

If you can see the pulley move when you move the blades, either the fan mounting bolts are loose or the WP bearing is bad. Most likely the bearing.
D


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While the blades are not loose, there is some play in the assembly.
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[aeronca65t]

As Dave say, it sounds like a bad water pump. If the fan bolts are tight, the "play" at the fan tips shouln't be more than 1/8". If it's bad,and you keep driving it, the pump may fail, allowing the fan to go through the radiator.
To "prove" that it's the water pump, remove the fan belt and rev the engine...if the noise has gone away, you've proved that it's related to the pump (or generator). Note: Never run the engine without a fan belt for more than a minute.

 

[jackathy]

Thanks for the quick response. When turned there is no play. If I hold a blade and push towards the engine, there is a slight play in the pulley. There is no left/right play. Would I need to replace the WP itself if this was the culprit?

Today is the 4th consecutive Great Driving day in CT. Most days this summer you had to keep an eye on the sky and be ready to raise the roof.

 

[jackathy]

The play is no more than 1/8". Tonight after work I'll 'test' the pump. Thanks for the clue.

 

[piman]

Hello Jackathy,
I have just replaced the waterpump on my wife's Morris 1000. (Same basic engine as your Spridget) There was only a slight amount of play at the fan blade but the noise was terrible.
New pump and all is nice and quiet again.

Alec

 

[Dave Russell]

I guess that your choices are to either have the mechanic fix it or to go to the ear doctor.
D

 

[jackathy]

I talked to my mecahnic today and he thought the water pump, if it was going bad, would make a lot more noise. The sound is not loud, and it is sporadic (every 30 seconds or so)and sounds like a metal tag knocking against something metal. With all the other noises going on, i'm beginning to wonder if it isn't just a case of Tinnitus!

 

[spritenut]

Check the generator fan and or pulley.
The water pumps (when they go bad) do not make a metal tag noise as you discribed. They make more of a groaning noise when the bearing goes bad. The generator bearing or the woodrift key on the fan of the generator make a distict metal flapping noise.

As someone suggested, run the car with the fan belt disconnected. If thge noise stops, just spin the generator by hand, or hold the pulley and see if the generator fan is loose.
If the noise is still there with the belt off, suspect the timing chain.

Good luck
Frank

 

[jackathy]

The fan belt is off and all noises are gone! So does that mean the water pump is probably the source of the strange noises? It sounds so good with it off it's a shame I can't just run that way. And today must be the best LBC day of the year so far. Thanks al for the hints and suggestions. This list is the best, but can't an hones person not given to bribes score some points in the rally?

 

[jackathy]

So, impetuosly, I took off down the drive and up the street, without a fanbelt. The temperature soared and I made it back just in the nick of time. It was at 212 degrees. Up onto the ramps I drove and the water started pouring out from somewhere under the generator. I couldn't see exactly where. Did I just overheat and will be somewhat whole when I put the fanbelt back on, or have I just gone where I should not have gone and will be paying dearly for my little ride!

 

[Dave Russell]

Jack,
It is proving to be very difficult to help you. It appears that either you don't understand or just ignore the very good advice that various people have taken their time to provide to you. There have been several suggestions about the water pump & a good one about checking the generator fan. So far, you have only reported that you removed the fan belt. Then you ignored Nial's advice -"Note: Never run the engine without a fan belt for more than a minute."

As to whether any damage was done - it depends on how long it was run & how hot it really got. The temp gage will not tell much when the water pump is not running.

Maybe you would be better off to just drive the reliable Miata & forget working on cars. LBC work is for people with a lot of patience & some basic understanding of how things work. Sorry to be harsh, just trying to get through to you.
D

 

[jackathy]

And I take the criticism well, because it is well deserved. I did remember the advice not to run it for over a minute, and while I obviously ignored it, I 'reasoned' that standing still and running and driving without a fan belt were 2 different things. I had the fanbelt go on my golf and I drove home because I was on the highway so it was air cooled.

I started down the road of LBCdom as only a driver, but learned that it would be very expensive if I didn't try to fix it myself. I have a long learning curve complicated by a slight bent towards rash behaviour. When the fan belt was off and it sounded SOOO good, I made a rash decision to just go up the street and back. I think it is leaking at the Water Pump gasket, so I'll replace both.

Do I get a second chance? After all it was the lure of the road that drove me to act rash!

Jack

 

[jackathy]

As a final mea culpa! I drove without a fan, not a fan belt. All the difference in the world.

Jack

 

[Dave Russell]

Hi Jack,

Of course you get another chance. Interesting aside. I once broke a fan belt & decided to try driving the car. The hood was off so that I could see the fan. When I got up to around 60 the fan started windmilling & turning the water pump. I got home by a little speeding & some luck. When the car was slowed to about 45 or under the fan quit turning.
D

 

[jackathy]

I replaced the water pump today and the noises are gone! Apparently there were other noises I had accepted as 'usual' that weren't. The Water Pump pulley was the most difficult part of the process. It was rusted onto the WP and only after soaking in WD-40 and Naval Jelly did it release it's grip on the WP. A 'puller' I borrowed only seemed to distort the pulley and I finally resorted to holding onto the pulley and hammering the WP. None too soon, as it is time to drive to Lime Rock this weekend. Thanks for all the advice!

 

[Dave Russell]

Jack,
This is great news, glad evertyhing worked out.
Thanks for the update.
D

 

[CDK]

Jack,
If you did not get a new pully make sure the old one is stright.With the engine running it is very noticable from the side view.As you will learn removing pullys takes alot of paitences so that you do not distort them.And having them correct is important to both the device and the belt life (including how long it stays on)As long as you learn at least a little each time your doing good."I know 10,000 ways a light bulb doesnt work" T.Edison one of my favorite quotes.
I went to Lime Rock today and had a great time.Now if I can just figure out how to budget the payments for the Bugatti into next months bills I will be all set.
CDK

 

[aeronca65t]

I guess that makes 4 of us from BCF that were all at Lime Rock this weekend. I was there, and so was "coldplugs" (John C.)...I got a chance to chat with him....fun to talk to another "eclectic type". Too bad we didn't know you'd be there (I was thinking of entering in Group 7, but the SVRA fees are $800....too much!....I'll be club racing at Lime Rock on Nov 1st (for a lot less money).
Two of the guys racing there were named "McCabe" (my last name)....one had a gorgeous AH-100-4 and the other had a Bugatti Type 35....must be from the rich side of my family.
The Bugatti guys were telling me that they had just come from the Monterey Classics, and were on their way "home" (many were Brits). I counted 11 Type 35/37s (and other Bugs) in the pits....apparently one of the largest groupings of Bugatti ever.
I don't think there's any sports car more "pure" than one of those firebreathing Type 35Bs. I told the missus that I'd even sell the plane if I could buy one....and she says "Great, but you'd still be about $950,000 short!"

Note: Jackathy-glad you got your noise problem worked out!

[ 08-31-2003: Message edited by: aeronca65t ]</p>