99 suburban overheating in traffic, Causing clutch to lose pressure?

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by juctenner, Aug 7, 2014.

  1. juctenner

    juctenner New Member

    Hi, guys im an Aussie who purchased a 99 7.3L 2500 suburban in L.A and am in the process of driving it down to Panama, Im currently about half way in San Christobal, Mexico and to say the suburban has had problems would be an understatement.

    Its got 107,000km on the clock and since l.a i have replaced the following:

    The radiator in San Diago

    The tranny rebuilt it La Paz

    Engine seized up and rebuilt in Salina Cruz (have only driven 5 hours since the engine rebuilt and now but made the 5 hour hwy drive with ease)

    and now the the brakes fixed and a new oil leak repaired today

    and gone through about 7 tyres (my fault cause i buy ****ty tyres)

    but why i joined the forum was to ask you all about a problem i cant get my head around, when the car is cold the tranny works fine and all gears seem to work well but when ever i am stuck in traffic the car heats up super quickly and i cant get any power to the wheels, I have no idea why this is happening.

    I have read heaps online but cant find anything specific.

    Could i need a transmission cooler?

    Or the water pump?

    Or could there be something wrong with the fan clutch for the radiator?

    thanks so much for your help, Want the old girl to make it all the way down as i love the car.
  2. crick

    crick New Member

    Do you have a transmission cooler? It would be easy to spot as there would be two metal lines coming into the passenger side of the radiator. Next to the battery.

    Could be that some debris got lodged in there and is preventing the trans fluid from circulating when the transmission heats up. The trans cooler is in the middle of the radiator and you'd have to replace the entire radiator to get a new trans cooler.

    A way to test it would be to figure out which is the return line and unscrew it from the radiator with the car running. If fluid is pumping out then that isn't the problem.
  3. sbower1976

    sbower1976 Member

    when you say it heats up super quick do you mean over heat or just to the 90 deg c and once at normal running temps the transmission won't engage the wheels ?
    If it only heats up when stationary i would be looking at the fan clutch as when driving the air passing through radiator would be enough to keep things cool but when stationary if the fan doesn't engage then you'll heat up. I would check that and also change tranny fluid as the oil you have might be burned out or the wrong spec dextron III , but i was in the shop the other day and saw castrol did ATF Transmax 3 fully synthetic and noted on the back that it was specifically designed for GM

    Hope that helps mate , Im Scottish in Norway by the way with the all famous chevy reliability , picked mine up 3 days ago and the list is massive already with 215,000 km on the clock

    good luck and let us know how you get on will ya

    ps if its ok whilst on the move i doubt you have a blockage

  4. juctenner

    juctenner New Member

    hey guys thanks for the replies as i want to get it fixed asap. There are 2 metal lines going into the passenger side of the radiator one at the top and one at the bottom. Does this mean i already have a transmission cooler when we got the new radiator in san diago i remember the shop telling us that the radiator has 2 oil coolers i dont know if this make a difference?

    I think the temperature gauge is cooked on the car as it never moved above zero, but you can feel the heat inside the car and when you are in the passenger seat if you touch the steel part above your feet sometimes it is to hot to touch and that is after only 15 mins driving in traffic.

    I want to get this fixed asap so thanks heaps for your reply as the next stop is Guatemala and i think parts are going to be near impossible to find there!
  5. sbower1976

    sbower1976 Member

    i would be looking at the fan clutch mate
  6. Paladin

    Paladin Active Member 2 Years 100 Posts

    You said you had the radiator replaced. Perhaps they did not bleed it properly and there is still air trapped in the cooling system preventing the coolant from circulating properly.

    Remove the cap from the coolant recovery tank, start the engine and turn on the cab heater setting the fan speed to full. Once the truck reaches operating temperature, let it idle for about 10-15 minutes. This should remove any trapped air in the system.
  7. juctenner

    juctenner New Member

    This could be right as when they rebuilt the engine they took the radiator off again. So do you mean take the pressurised cap off the top of the radiator and let the car run? or take the non pressurised cap off the overflow and let it run?

    Thanks for your reply.

    The fan clutch still doesn't spin freely this means its still ok right? it takes a bit to push it and it will never spin on its own. Or can there still be a problem with it?
  8. Paladin

    Paladin Active Member 2 Years 100 Posts

    If you do have a radiator cap, remove that before running the engine. Make sure to to keep the coolant at the proper level.

    As for the fan clutch, the fact that it does not spin freely is a good sign. A free spinning fan will not turn fast enough to keep the engine cool. Oddly the fact that your vehicle is overheating in traffic is indicative of a "loose" fan which you do not seem to have.

    My bet is on air in the system.
  9. juctenner

    juctenner New Member

    Well turns out the transmission was repaid by a scammer and its gone to **** again. I ran the car to get air out of the system then went to take it to a mechanic to be checked out turns out no mechanics are open in san christobal on sunday so i decided to drive the 45km to the closest larger town with mechanics open and also wanted to test the car on the open road and the transmission started slipping about 10km into the drive on the first decent hill and i was lucky the rest of the way was a roll. As soon as i got into the town and the first army checkpoint i could get no power to the wheels. I tried to get a tow truck at this point but they also are not open on a sunday and the army wouldn't let me leave my car there. After the car cooled down a bit i got it to a decent mechanic and could not have gone any further. There was only a kid working though and have to wait till tomorrow to know the extent of the damage.

  10. sbower1976

    sbower1976 Member

    Unlucky mate :( sorry to hear the bad news

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