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(Post Link) post #1 of 3 Old 12-03-09 Thread Starter
Status: Finished the 166 overhaul (whimper!)
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Hmmm How do you know if....

Hi guys a tech question of course for my QV -
I have done quite a bit - have scrounged enough to buy one of alfissimo's boots for the airbox (hallelujah!) - and now....
When she's cold, the engine positivly whines...and when shes's toasty, its almost silent apart from a happy V6 growl. Which means - and this is where I am not sure and need some sage advice from you all:

1) The hydralic idler is full of s**t, and needs to be replaced. Alfa can do it for NZ$200 for the part, and I am not sure of labour, but if I combine it with an oil change, not so bad.

2) Its the belt itself - though : I have sprayed anti-slip spray liberally on the belt as the engine was running, and the power is way up ( ), but....the sound got WORSE, though it got better at toast temperature. Incidentally, the water pump appears to be doing a better job of keeping the car cool, a result of the gluey stuff perhaps ? comments please....There was an Alfa Tech bulletin covering my car, and so far there has been no belt reaplcement.

3) The water pump has had it !

So - I have listened to the water pump while the engines been revved by a mate with ye olde screwdriver, but it seemed ok....I hope, Alfa Auckland's gonna take a look on saturday morning.

Is there any way of telling if it well and truly is the water pump bearing ? Is there any way of being certain that its the idler bearing ? clues to me have been that the sound is quite muted when standing above the engine, and it seems to be bouncing out from under the car, which is a hopeful sign...but I could be DEAD WRONG, and so would appreciate ANY and ALL advice, from the sage to the flippant, and I hope get some consensus.....

I love this car, its a total MF to drive, and since the belt spray and new brakes a hoot thanks to power and brakes together...apart from the unprintable screech.....

Thanks all.
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Re: How do you know if....

Not quite sure I've got a grasp of the problem, but here goes:!

First of all, is it the 12 or 24 valve engine?

Secondly, what sort of auxillary belt(s) does it have to drive the aircon, power steering and water pumps (and alternator)?

Some early 12 valves had separate single V belts and later ones had a ribbed "poly-V" belt. Not sure what the 24 valves had.

I don't think the hydraulic cam belt tensioner can make a noise due to anything hydraulic. The bearing in it could make a noise though if it was on it's way out. If it were my car, I'd take off the auxillary belt(s) with the engine cold and then start it up to see if the noise has gone. It won't do any harm for a few minutes. If the noise goes, you'll know it was either the water pump, power stering pump, alternator, aircon pump, or an idler / tensioner pulley. If it doesn't, you'll know it's something to do with the cam belt side of things. You could also check the water pump for play whilst there's no belt tension on it. On my old 12 valve, it made more of a grumbling noise than a whine when it went and there was very obvious, visible play in the bearing (and it was leaking!) so it was pretty obvious!
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(Post Link) post #3 of 3 Old 24-03-09 Thread Starter
Status: Finished the 166 overhaul (whimper!)
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Re: How do you know if....

Well after all that....Ishii-san at Kauri Auto's replaced both cam belt, which will give me 100,000 kms or 10 years joy, and the worst of the thumping is gone. Got an OEM waterpump for very little, about $150. And then...oil change as well, also new filter, and then...the V-belt I had bought was the wrong one ! wail ! Old one is still there...the 166 V-belt has 7 nothces, but the 164 (same engine!) has an 8 notched belt. Whats that about ? does anyone know if they both fit ?

But though its not so bad. resprayed the belt, now going to try ye olde soap trick , see if it works, experiment tomorrow morning, I am getting pro at removing that mudguard shield now.

After the new cam belt (Ishii-san kept the wheels and crank locked while doing the change), there is something really cool out of the engine bay - a rasp ! its acutally rasping as it comes onto the cam. And its not a bad rasp - the temps not going wild, there's no detonation, if anything its running really this an effect of the new cambelt perhaps ? the cams are not out of kilter either .... they are in fact running very sweetly.

This rasp reminds me of the sound made from a well tuned V-8, and perhaps its the same thing - everything is running really well !

replacing the fluids also involved dropping Red-line Water-wetter into the system, to prevent the bearing from going bad again. But it has an wonderful effect - the car does not get as hot as it used to, which might also be responsible for the rasp - better cooling at rpm, which them means that compression improves ever so slightly. there is a 30% improvement in cooling over all ! this stuffis magic - drain your beast and give it a try, it seems to help a lot, and it certainly does not hurt. If its good enough for A1 GP and NASCARs, it can't be bad.
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