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Hypothetical Question


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Since the other thread got locked for some reason.

 

I stated that I noticed my alt/waterpump belt was loose on my coupe. This was after its emergancy shut off and the smoke cleared from the garage..upon restart after it cooled off good.

I think I already know the answer but just want to make sure... is it possible that it stretched or the adjustment on the tensioner slipped some...caused this and now the water pump is not turning as it should causing the coolant to not circulate fast enough...leading to its over heat?

 

I have 4 days off work soon and I might look into it some more over the holiday

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The lack of the water pump not turning as it should will certainly cause the engine to overheat. I would say the most likely senario is the water pump shaft may have seized up or has something else went wrong with the pulley system, like the idler pulley.

Edited by Cougar
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water pump did not seize..and all new pulleys..plus the car has a modified bracket to allow for an XT6 alt instead of the EA81.And I am going to disagree with you on the idler pully..just walked out an checked. belt from crank to water pump to alt loose.pulley is fine...I can also turn the water pump by hand right now.I am still thinking the belt went loose ( which the belts are brand new on the car along with the water pump).

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Yes, a loose drive belt for the waterpump can cause an engine to overheat.

 

On these little engines of ours, there's not much "belt wrap" around the pulley on the waterpump to begin with, a loose belt is not a good thing.

 

I wouldn't rule out a sticky T-stat yet either. I've had that happen to me more than once with a "new" T-stat.

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Yes, I Agree with the Sticky Thermostat Idea... Also a Damaged Hose Could be There... Some time Ago, the 5/8" Hose that Comes from the Water Pump to the Heather, in my EA82 Wagon, had a Tiny Hole, very minimal but when Water / Coolant Reached Hig Temps, it comes out like Vapor, from that Damaged Hose... Maybe Somethin` similar is Happening there too... Also you must Search for a Damaged Ball Bearin` from Belt`s Tensioners...

 

Just a Li`l Question: Why the Other Thread got Locked?

 

Good Luck with Your Coupe!

Edited by Loyale 2.7 Turbo
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Since you found the items I suspected possibly may have caused the belt to come loose are ok then perhaps something else may have caused the trouble, maybe the power steering pump. Or perhaps the belt was loose from the beginning. In your first post about this, in the original thread, you stated that you heard a loud whining sound. I suspect the sound may have been from either the loose belt trying to drive the pulleys or it was from one of the devices the belt is driving. The only thing I can think of to find out if there is still a problem is to tighten the belt and see what happens. If the noise comes back try to pin down the source of it. If it doesn't return then the belt was most likely just loose to begin with.

 

On a different thought about this, if the thermostat did get stuck perhaps the pump wasn't getting any coolant, which acts as a lubricant for the shaft, and the noise came from there.

Edited by Cougar
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On a different thought about this, if the thermostat did get stuck perhaps the pump wasn't getting any coolant, which acts as a lubricant for the shaft, and the noise came from there.

 

That would make sence if the noise then stopped when the car was shut off...but like I stated in the closed thread somewhere..the whining went on for a good minute AFTER the car was shut off...which was explained to be the pressure being released from the overflow caused by the boilover

Edited by Bucky92
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That would make sence if the noise then stopped when the car was shut off...but like I stated in the closed thread somewhere..the whining went on for a good minute AFTER the car was shut off...which was explained to be the pressure being released from the overflow caused by the boilover

 

Ok, that wasn't clear to me in your first post. When I read it, it sounded to me that the whine stopped with the engine shutoff. So since the engine was shut off the sounds you heard weren't really any mechanical sounds, just sounds due to the high pressure of the coolant.

 

I guess my first thought of the stuck thermostat is what I have to go with and it appears others think that may be the case also.

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Have you checked the intake manifold gaskets? Perhaps one is leaking - they are notorious for being difficult to install and for non-OEM gasket failures.

 

You are probably right about the water pump. If you can spin it by hand with the belt still on then the belt was not tight enough. Belts do stretch and perhaps it wasn't all that tight to begin with.

 

Start by removing the manifold and inspecting the gaskets there.

 

GD

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Have you checked the intake manifold gaskets? Perhaps one is leaking - they are notorious for being difficult to install and for non-OEM gasket failures.

 

You are probably right about the water pump. If you can spin it by hand with the belt still on then the belt was not tight enough. Belts do stretch and perhaps it wasn't all that tight to begin with.

 

Start by removing the manifold and inspecting the gaskets there.

 

GD

 

Yeah when I first started working on subarus I was told by a subaru tech that those belts should be "Hummin' tight!"

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As far as "loose belt" issues go. You need about 7/16" (1/2" max) deflection of the belt between it's two longest runs, (being the upper side of the alt to crank pulley on my '86 EA-81 engine ,no AC, no PS). Any less than that, and you can stress the bearings/seals of components, any more and you're not turning things that need turning like they need to be. Plain and simple.... Loose belts slip, over-tight belts put un-needed stress on things.

 

The new belt may have been just a tad wide at first, then,,, with the running of the engine, it wore enough to fit the pulley groove as it really should, thus giving you a "loose belt" condition.

 

I would re-tension the belt, top off the coolant and fire that mother up:headbang:Keep an eye on things as far as temps and what not, but I believe it to be okay. Still have the possibility of an iffy T-stat, but probally was just the loose belt.

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