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7.3 over heating

Discussion in 'Truck & Equipment Repair' started by DOGHOUSE, Mar 3, 2006.

  1. DOGHOUSE

    DOGHOUSE Member
    from Alaska
    Messages: 36

    Hey Guys, Just Today Found That My Upper Radiator Hose Was Collapsed And Then After A Minute Or So Went Back To Shape. I Thought It Was Just A Bad Hose So I Replaced It. A Couple Hours Later Traveling Up The Same Hill The Truck Was Starting To Over Heat Again. What I Have Is A 1992 F-250 With A 7.3 Diesel. All This Trouble Is Starting Me To Think It May Be The Thermostat. If Any Of You 7.3 Drivers Know Where It Is And How Much Trouble It Is To Get To Could You Please Let Me Know. I Think It's Behind The Alternater And Power Steering Pump To The Bottom Left Of The Intake, ( Major Work To Get To ).

    Thanks Guys,

    Dave
     
  2. douglasl330

    douglasl330 Senior Member
    Messages: 356

    Yep you know the spot! Uum could it be that the waterpump is on it's way out? I have heard of the top hose collapsing but I cant remember why!!! I think it was just from old hoses,but can't remember! There are a couple of great diesel forums also you may want to shoot a line to!--best of luck
     
  3. justme-

    justme- 2000 Club Member
    Messages: 2,138

    top hose collapses from vacuum. coolent gets hot and expands, overflows into the overflow res. When the engine cools the coolent shrinks causing vacuum in the system which is supposed to draw the coolent back in the system from the res. If it can;t return the vacuum in the system now created will collapse the hoses, the majorly reduced amount of coolent is not enought to cool the engine and the vacuum constricts the coolent flow so you overheat.

    something is blocking the flow back from the res- check the rad cap and the flow tube to the res and the res container all for contaminates. something could be blocking the hose when the engine sucks the coolent back and gets blown clear when it adds to the res. Change the rad cap- it's cheap insurance and unless you have a pressure tester you can;t test it anyway. If the spring is going or the gasket is going it can block the flow too.
     
  4. douglasl330

    douglasl330 Senior Member
    Messages: 356

    Hey doghouse--I remembered something--I know the older trucks also ran an internal spring like tHing in the top hose from keep it from collapseing. Obviously your truck doesn't have one. see if one from a 6.9 at the parts store will fit your truck and if it has the internal wire in it.--Then follow just me's suggestions he is pointing you in the right direction. Because there is a cause for it to be collapseing which you need to find.
     
  5. MickiRig1

    MickiRig1 PlowSite Veteran
    Messages: 3,617

    Is your fan clutch working? I would go with the thermostat being the problem.
    Buy a good one too heavy duty if they have them. Have them look it up at the counter so you get the right one.
    Clean and flush the whole system when you replace it.
     
  6. DOGHOUSE

    DOGHOUSE Member
    from Alaska
    Messages: 36

    Thanks

    Well I Found The Problem. Took The Old Thermo Out And Replaced It With A 165 ( Came With A 195 Which Didn't Leave Alot Of Cooling Range ) And Tested It In Boiling Water On The Stove. It Never Opened And So Far Problem Solved. I've Driven Up That Hill Like 6 Times Since And The Gauge Has Stayed In The Midrange. Thanks For The Help Alot Of Good Things To Look For.

    Dave