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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: gmcthunder on May 14, 2014, 08:08:13 am
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In recent days, my engine has been running hotter than normal (210) at about (225-235) and sometimes even going into the red on my gauge. I noticed yesterday, that I had a puddle of fluid under my truck near the front of the engine. Looked to be coming out of where the radiator hose goes into the front of the engine (water pump???) I am assuming that my water pump is probably bad and needs replaced. Also, the fluid was very rusty, which I don't think is uncommon for a 29 year old truck. Any advice on what to replace (water pump, thermostat, radiator, etc.) would be appreciated. Thanks in advance.
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Assuming this is a sbc v8, There are two main radiator hoses. The upper hose runs from the top-driver's side of the radiator to the thermostat housing(dome shaped thing with a pipe connecting to the hose and possibly some sensors w/ electrical connectors) that is attached to the top of the engine on the intake manifold (right in front of your carburetor), the thermostat is under this. The lower hose runs from the bottom-passenger's side of the radiator to the water pump(attached to the front of the engine behind your belts/pully's.
Hoses can begin to leak when they are old. Look for cracks or bulging in the hose where it attached to the thermostat housing/water pump. also squeeze the hose here and in the middle to see if it feels softer near the connections.
A bad water pump will usually leak from a small "weep hole" on the bottom of the water pump. With a bad water pump, the engine will warm-up normally but then begin to overheat rather quickly.
A bad thermostat will cause overheating or long warm-up times (depending on if it's stuck closed or open). A bad thermostat by itself will not leak, but the gasket between the thermostat housing and the intake manifold can start leaking.
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I had near the same problem with my 86 K10. Every time it got hot it would start leaking and various hoses. Replaced everything i could think of with no change. WP, Theromostat, hoses. Finally i decided to replace the radiator and bang its never ran hot again. $125 at local parts store in stock.
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Thanks timthescarrd. I will look into the different things that you have talked about. parisherj I figured it may be something like that. I planned on putting a new radiator, wp, hoses and thermostat anyways while I have everything else out of the way. Thanks.
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is the rad look all gummed up? could flush it. but check the weep hole, like stated when it gets hot it builds up more pressure than normal usually the rad cap should open and let the pressure off.
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I did notice that by the rad cap I saw antifreeze dripping down the radiator.
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by the overflow vent or leaking pass the cap?
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I believe the cap but not 100% certain.
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if your cap isnt holding pressure your coolant will boil at a lower temp 212°(water)-223°(50/50) you gain 3°per psi of your rad cap. our caps are about 15psi so this would add 45° to each temp 257°(water)-268°(50/50). if your cap is leaking it will allow the coolant to boil and boiling fluid isn’t very good at transferring heat. and you are leaking coolant which will reduce the amount of cooling your coolant can do