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73-87 Chevy _ GMC Trucks => Suburbans => Topic started by: paintinx on September 17, 2016, 01:21:43 am
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good morning :)
i am currently changing all hoses of the water/cooling system at my suburban79.
but I caNt find a description for the two screws at the special part I have tagged
on the picture.
how many NM or LBS should I use?
the same question I have for the fuel (gas) filter on my carburator.
there is only a nut - so I guess there are no special NM/LBS counts.
thx in advance and have a noce weekend :) stephan
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The fuel filter for the carb can just be snug tight with a wrench, you don't want to tighten it alot, it will damage the fittings. As for the 2 screws (bolts) for the item in your picture, (called a water neck or thermostat housing) I don't remember the exact torque but I think it's like 25 LBS, maybe even less, but you could do 20 or 25 and it would be fine. Pretty sure it's no more than 30, there's no requirement for that part to have any more than that much torque on it.
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You really dont need much pressure at all. To be honest hand tight with wrench and then another 1/4 turn would be just fine.
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The OEM water outlets were manufactured from aluminum. GM decreased the specified torque for the water outlet bolts in stages from 30 ft-lbs in 1979 to 21 ft-lbs by 1987, because they discovered that the aluminum housings had a tendency to crack and the higher torque initially used was unnecessary to produce adequate crush on the gasket. To keep from cracking the water outlet during installation, make sure the thermostat is properly seated in its groove then tighten the two 3/8" bolts alternately in three equal stages to a final torque of 20-25 ft-lbs. Note that the water outlet is not a critical attachment. It is more important to have equal torque on the two bolts than to focus on an exact final value.
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Thx!!!