Stress cracks in fan

Post by **paintwgn** » Thu Nov 07, 2002 6:06 am

Just noticed stress cracks on the hub of the original radiator fan. Any history of fan blades coming off? Already bought a new one from Holman Infinity in Maple Shade, NJ- haven't installed it yet. Also, just had the guides done at 108,000 mi. by neighboorhood shop. Old guides showed no signs of delaminating. Now when engine first starts the cam chain makes a little noise until the tensioner fills with oil. Only lasts 2 or 3 seconds when parked overnight. Somehow the oil-activated tensioner is not holding the oil (Mobil 1 10w-30). Is this a serious problem? Otherwise my old Q is in mint condition and probably the nicest '91 in the Philly area.

Post by **landtodd** » Thu Nov 07, 2002 6:06 am

I remember reading Dennis saying he's seen it happen. If the fan comes apart, the most likely damage is to your $400 radiator. I just replaced my fan, too, because it had multiple cracks most of the way through the body. The new one was under $60 from Scottsdale.

(Anyone thinking about doing it -- this is easy D-I-Y. Anyone who wants to charge you more than 1 hour labor is pulling your leg.)

Did you replace the tensioners when the guides were done?

Post by **fxjackso** » Thu Nov 07, 2002 6:06 am

A pleasant side effect of a new fan is that it will be much quieter since the cracks seem to throw it out of balance. An easy diy, I agree.

Post by **DougQ45** » Thu Nov 07, 2002 6:06 am

Also having the same 2 to 3 second chain noise problem after replacing the guides. When I compressed the passenger side tensioner, I heard the "squishing" noise of the oil being compressed. Pushed the tensioner far enough in to secure the little metal catch on the tensioner. Did not replace the tensioner with a new one. Should the tensioner be replaced??

Post by **911/Q45** » Thu Nov 07, 2002 6:06 am

I replaced my guides and not the tensioners and haven't had the problem. You did release the little hook, didn't you?

Post by **DougQ45** » Thu Nov 07, 2002 6:06 am

I'll let you know Monday when I open it back up. Was thinking the same thing.

Post by **DAEDALUS** » Thu Nov 07, 2002 6:06 am

Just to confirm, by 'open it back up' you mean the oil check cover, right? Nice to see we finally found a REAL benefit to the plate.

Post by **DougQ45** » Thu Nov 07, 2002 6:06 am

Yeah---for starters. Was also thinking about the whole front cover too. Remember all that slop in the oil pump chain???---it has me very worried. When I did the silver 1990 I replaced the oil chain and tensioner guide. Now that I have done it a few times, it is not as intimidating.

Post by **DAEDALUS** » Thu Nov 07, 2002 6:06 am

You mean the slop that was there before the guide was adjusted? You're thinking the chain stretched and is at risk of breaking? I've never heard of a broken oil chain. Hopefully Prof Mike or Q45Tech can tell us if this is much of a risk.

Post by **landtodd** » Thu Nov 07, 2002 6:06 am

Dennis has said in the past that the strangely delicate oil chain works harder than the robust cam chains, and should be replaced as a matter of course in the chain-guide job. He has also suggested replacing the oil pump itself if you have the cover off and have more than 150K miles on it. If longevity is your goal, these suggestions seem reasonable to me!

Post by **Q45tech** » Thu Nov 07, 2002 6:06 am

The tensioners should ALWAYS be replaced as the varnish caused by not changing the oil every 90 days] inside can never be cleaned. In fact this [varnish] can be a problem on even later model engines delaying the pump up and corresponding chain tightening. The internal spring in the tensioners gets weak or fails!Our cheapo guide service incluses new tensioners and oil chain and a new oil guide.

Post by **getatu** » Thu Nov 07, 2002 6:06 am

change it as soon as possible notice a small crack in mine paid it no mine three month later on the high way blades sheared off cut into the radiator cut the atf hose fitting tranny fluid every where...a 85 dollar fix ended up costing me 500

Post by **Q45tech** » Thu Nov 07, 2002 6:06 am

If it had been metal it might have come through the hood....or at least presented you with an expensive dent.

Members must remember the fan can turn 20-25-30% faster than on typical V8 American cars due to the 6900 rpm redline on our performance engine. Then there is the case of the locked [failed] viscous unit.

Stress cracks in fan

Stress cracks in fan

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