Duramax Themostat ?

Discussion in 'Mechanic and Repair' started by bob, Oct 9, 2009.

  1. bob

    bob LawnSite Platinum Member
    from DE
    Messages: 4,260

    I think my 02 Duramax, needs the thermostats replaced. It's been running cooler than normal. How involved is this job? Are there any links to explain how this is done?
  2. loafycleetus

    loafycleetus LawnSite Member
    Messages: 36

    This job is a bit involved but not too bad. The hardest part is unbolting the coolant pipe from the valve cover and fishing the pipe out from under the ac lines. Make sure that you pull the coolant line that runs to the turbo. There are four longer bolts that hold the housing down, you will find two t-stats, the front has a valve that blocks the bypass and the rear has the bleed holes, it has been awhile so if I am wrong, sorry! Just take a note when you take it apart. I have never taken the pipe out of the thermostat housing if iw was not leaking, just remove it as a entire piece. If you do take the pipe apart, get a NEW o-ring and lube it up good with vaseline. You must be sure that the o-ring doesn't roll. The LB7 is easier than the newer ones, less junk in the way of the valve cover bolts that hold the pipe. Hope this helps, it seems involved but does not take more than 30-45 mins. If I had to guess, the rubber seals in the t-stats are cracked, seen it a ton of times.

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