Whine from engine when cold

[zcacogp]

Chaps,

Vague thread description, vague symptoms; my S2 has developed a number of annoying small faults since it has been used less frequently, and one of them is a whine from the engine when cold. Noticeable even inside the car, and it goes away within 5 minutes or so.

It seems to be coming from the front of the engine, and having checked the belt tensions they are fine. (A smidge loose, if anything.) Belts were changed 12 months ago, as was the waterpump.

Anyone have any ideas? It has started recently, so may be related to the cold weather.

Thanks,


Oli.

 

[robdimond]

I noticed mine doing exactly the same yesterday, first run after a few weeks of no use, also went after five minutes. In my case the noise going away MAY have been related to putting the clutch in and out a few times in neutral.

I also get a bit of a squeak when the steering is at full lock
Main concern for me is that I still have the original waterpump (183k on it, no evidence of a change).

More worrying for me is a ticking from the top-end... seems to happen while the engine is warming up... not when it's completely cold or completely warm. Did the tensioner slippers about 1.5k ago.

Sorry Oli... I suppose that's not very helpful but my S2 has some funny noises too!

 

[zcacogp]

Rob,

944's always have some funny noises - my S2 particularly! Whine when cold is the latest (and perplexing) one, and I am wondering whether I ought to re-check the tension of the balance belt; it seems to be a common cause of whines, although they aren't temperature-related. The O/S boot catch wasn't catching particularly well recently, so one long Christmas journey was accompanied by a constant chatter from the back (accompanied by a god 'ol rattle from 25 or so empty jam jars for the MiL). Apparently the gearboxes whine as well (mine doesn't), so you can throw that noise into the mix. And, to make things weird-er, my S2 makes a very duck-like quacking noise from both doors whenever it rains. Yes, really. And yes, I have been laughed at for that on here before ... [X(]

944 = Mobile Percussion Orchestra. Sometimes.


Oli.

ETA: Original water pump at 183k miles is good going. Apparently the big fear is that they can jam and cause a cam belt failure, which you would do well to avoid. Although, more often, they just leak ...

Ticking from the top of the engine is either injectors or tappets. Injectors are nothing to worry about - just turn the radio up. Tappets can be improved by an oil change with a flushing oil; there is a wynns product which is recommended by PCGB, I think, that I tried once. It did help a little. I think it's this stuff:

http://www.tools4trade.com/d-1145006-wynns-engine-flush-425ml.aspx

... although others will confirm.

 

[mr brightside]

Does it sound like a water pump whine? Mine's got a whine just like this. So similar is it to a water pump that i had the pump changed at a cost of £540 iirc only to find the whine unaffected! The only thing that hasn't been changed is the PS pump; i could disconnect it and start it up, but the car has been running fine with the whine for so long now that i've lost interest in it!

 

[bert gear]

in winter the Altinator is working harder with all the demand on battery till it has replaced what it takes to start, hense more noise

 

[zcacogp]

ORIGINAL: bert gear

in winter the Altinator is working harder with all the demand on battery till it has replaced what it takes to start, hense more noise
 

Bert,

Really? Thanks! So it really could be nothing to worry about ...


Oli.

 

[robdimond]

Thanks Oli.

I also have to deliver empty jars to my mother in law so can relate to that rattle.

Pretty sure the ticking is not the injectors... I can hear it separately from them. The strange thing is it's only during the warming up phase... doesn't do it when the engine is really cold or warm. Thanks for Wynns tip... will try it on the next oil change.

I'm preparing myself for a cascade of replacement parts when the belts are done again next year...

first change the belts
THEN, because the new belt could cause the old water pump to fail, change that
THEN, might as well change the cam chain, while the timing belts are off because that has never been changed as far as I'm aware
THEN, need to change the cams, because some people say a new chain on old sprockets can cause the teeth to break off...
THEN, while the cams are out, might as well replace the head gasket (because they rot and then the coolant can short circuit)
THEN, while the head is off, might as well get it rebuilt with new valve springs and seals

Agh!

 

[ukmastiff]

Ive had this with an alternator before

regards

mas

 

[mr brightside]

ORIGINAL: zcacogp

ORIGINAL: bert gear

in winter the Altinator is working harder with all the demand on battery till it has replaced what it takes to start, hense more noise

Bert,

Really? Thanks! So it really could be nothing to worry about ...


Oli.

If Bert is right, you will hear the whine return or strengthen in amplitude when you flash the full beam or something. Assuming i've interpreted his post correctly, that is, and that he is attributing the whining to an increase in alternator output current.

 

[zcacogp]

Mas, thanks.

ORIGINAL: mr brightside
If Bert is right, you will hear the whine return or strengthen in amplitude when you flash the full beam or something. Assuming i've interpreted his post correctly, that is, and that he is attributing the whining to an increase in alternator output current.

I read it in the same way. And yes, you are right ... BUT, the alternator will be re-charging the battery from the energy put out to start the car, which will be a significant amount and hence the alternator will have to work hard until the battery is re-charged (and 5 or so minutes sounds about right) . Turning the headlights (and rear window demister, fan, radio etc) on will present a more steady, constant load to the battery and hence the alternator. It will increase the whine, but I wouldn't have thought by much. It will however increase the time the alternator whines for, as current is being used for the ancillary devices rather than to re-charge the battery.

Good point tho'. Thanks.


Oli.

 

[mr brightside]

Good luck farting around with it...i'm nailing my colours to your PAS pump []

 

[robwright]

ORIGINAL: mr brightside

Good luck farting around with it...i'm nailing my colours to your PAS pump []

I am totally with mrbrightsie with this one. I will put money on it being your power steering. When was the last time you changed the fluid? Have you ever refurbed the pump? Mine used to be awful for it. Changed the fluid and it went away.... for a while. Refurbed the pump and new fluid again and has been quiet as a mouse and silky smooth ever since. About two years now.

 

[peanut]

are you running a book on this Oli ? i'd go with the Alternator bearing as well. Mine has been whining like a goodun for nearly 3x years now as I've only covered 3-5000 miles .Sometimes the bearing friction is sufficient to make the belt slip and squeal but it hasn't done that for several months now .[]

can't help with the quacking noise though........[][][][]

word of warning to those considering re-tightening their belts ....I wouldn't []
Re-tightened belts are the biggest cause of failed water pump and alternator bearings. Most belts are over-tightened in my experience presumably in the mistakened belief that they will loosen in the first thousand miles or so to the correct tension.

I recently had a major service on my Transit Campervan and every fluid level was seriously over-filled . Oil , brake fluid, steering fluid everything . It seems you can't trust any garage to do a proper job these days.[&o]

 

[robwright]

The rear window demister will put a massive load on the alternator and will increase alternator squeal. The sound of a squeaking belt is a lot different to the sound of a dodgy bearing though IMHO.

 

[peanut]

ORIGINAL: robwright
The sound of a squeaking belt is a lot different to the sound of a dodgy bearing though IMHO.

yes it is but it is generally friction in the bearing (which produces the whine) that cause the belt to slip (producing a squealing sound ) My car exhibits both sometimes at the same time .

From Oli's description it sounds to me like it could be a dry bearing whine wouldn't you say ?In my experience it is frequently the increased tension from new belts that increases pressure on the alternator bearing causing the whine

 

[zcacogp]

Whoah! I go out for the evening and find that this forum has become William Hill and my S2 is the nag of the day!

So, todays runners, in order:

- PAS Pump. 171,000 miles old (original, if the car's history is to be believed). Fluid was changed a couple of years ago tho', and topped up a month or so back. However it may be an odds-on favourite as the reason I topped it up was because the fluid level was low, which caused the pump to whine. That whine went away with more fluid (and this whine is different), but presents two questions; a) What happened to the fluid and b) did running the pump while low on fluid cause this whine? BUT, if this is the problem, then why does the whine only occur when the car is very cold and why does it go away after 5 minutes or so?

- Belts. Let's be clear, there are four belts in the belt-race; starting from the front of the field (engine), they are Power Steering, Alternator, Balance and Cam. B and C were all changed recently (12 months ago) and tension is fine. PS and A haven't been changed in 6 years, but look fine and the tension looks OK too. (Although PS may be a smidge tight - perhaps I should loosen it a little.)

- Belts (second consideration). Discussing this with a friend last night, he said that belts can be noisier in winter than in summer as the rubber hardens and behaves differently. As they run then the hysteresis of the rubber warms them up and they behave more normally and quieten down.

- Alternator charging. A firm favourite, and backed by Mas and our very own PCGB Technical Rep Mr B Gear (esq). Already been discussed at length and has strong form in previous races.

- Alternator bearing. A bit of an outside candidate, although from the strong Nuts stable and backed by Nick, and apparently has form too. Can alternator bearings be lubricated?

- Belt slip squeal. Never got off the starting line - sounds wrong, feels wrong and just doesn't fit in this race. Nice try, and I'm sure it will do well elsewhere, but not here.

Any early results? Drove the car for 40 minutes last night, and it whined for the first 5 of those (although didn't seem as bad as usual this time.) Left it parked for 2 1/2 hours, then another 40 minute drive home during which time it didn't whine at all.

So, gentlemen, place your bets NOW! (And thanks for all your input. Anyone know how difficult it is to rebuild a PAS pump?)


Oli.

 

[peanut]

Oli I'd be interested to know what you find . My S2 has had the same whine for years . People say it sounds like a jet engine from outside the car ?[]

 

[rcsalmons]

Question - I understand turning electrical things on will increase the electrical load on the alternator but how can that possibly increase noise and mechanical load?

Rich

 

[sulzeruk]

The greater the load, the more power that the alternator has to produce, at higher RPM, this will be fine, at low RPM, there is a lot more drag due to the increased load and lack of revs to supply the load. Scam75 had a noisy bearing in his alternator, cure by changing it. Was squeaking, bearing was dried out and knackered.
Alasdair

 

[bertelli_1]

OP - Firstly I'd suggest squirting a little lubricant on the auxilliary belts, if the noise disappears just change the belts (assuming pulleys are ok).

There seems to be some confusion about battery loads & alternators here! The alternator doesn't work harder for the first 5 minutes to replenish the battery, or provide extra current if the battery is struggling. All it does is supply a steady 13.5v or so under all rpm & loads. The battery recovers very quickly after starting the car (usually the voltage drops to around 9v while cranking).