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Old 06-25-2006, 10:01 AM
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74fj40 74fj40 is offline
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Join Date: Oct 2005
Location: Highlands Ranch, CO
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Couple of questions -
-about heater hose routing - does it matter which way the coolant flows through the heater core?
-how does the fan clutch work? I know that the clutch is filled with silicone and that when a certain temp is reached the little thermostat at the front forces the silicone, and tightens the fan onto the metal rod it's mounted on - but, the fan always seems to turn, regardless of the temperature - does it just go faster when it engages?
-what to do about a broken heat riser and missing flap?

Originally Posted by treerootCO
  • missing o-ring on top of the thermostat 2Fs have them, not sure about F
    o-ring is there
  • too much antifreeze
  • too lean
    possible, but don't think so
  • too rich
    possible, but don't think so
  • too far advanced
    possible, but don't think so
  • too far retarded
    possible, but don't think so
  • thermostat not opening or opening too soon
    I tested it yesterday in a pan of boiling water with a thermometer - it's fine
  • cavitation
    not sure how to test for this
  • blown headgasket
    brand new oem installed correctly yesterday
  • wrong headgasket
    possible, but don't think so
  • timing is 180 off
    possible, but don't think so
  • oiling problem
    possible, but don't think so
  • bad sender or wrong sender
    brand new with new temp guage same issue with mechanical temp guage sender, which was also new
  • no fan shroud
    fan shroud installed
  • kinked hose
  • scale/blockage
    brand new radiator, head cleaned by machine shop, block inspected and cleaned
  • defective water pump
    brand new, older pump had same issues
  • loose fan belt
  • wrong or defective cam
    correct cam, possible that it's defective, but don't think so
  • miss adjusted valves
    valves adjusted by mechanic when preparing for emissions test
  • vacuum leaks
    possible, but don't think so
  • bad brake booster
    possible, but don't think so - new updated booster from a 4 runner, no leaks
  • choke not opening
    possible, but don't think so - carb inspected by mechanic
  • blocked radiator internal or external
    possible, but don't think so - new radiator
  • any kind of friction internally
  • heater hoses routed incorrectly
    see question at top
  • too much compression
    possible - will check
  • low oil level
  • cracked block/head
  • fan not close enough to radiator some years had spacers
    fan is about 3/4" from radiator
  • lead foot
    yep - but, heats up before we actually drive it
  • assembly lube in oil
    we've changed oil 5 times since rebuild
  • miss adjusted float level
    adjusted by mechanic
  • defective fan clutch
  • defective radiator cap
    new and overheating happenned with older cap too
  • restricted exhaust including that little flapper that usually is broken
    possible - heat riser is broken - flap missing
  • cracked intake manifold
    not yet
  • warped intake/exhaust manifolds or bad gasket
    new gasket, don't believe there are any leaks

1997 Honda civic DX( all stock DD)
1972 Toyota FJ40(4" lift, FJ60 axles, FJ60 4speed with split case, 35's, Detroit locker rear, Lockright front, Marlin Highsteer, 105"WB, Saginaw with GM tilt column, soon to have: 30spline longfields, inners/outters, toybox.
1967 Porsche 912(100% stock)

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