Forum Discussion

BurbMan's avatar
BurbMan
Explorer II
Dec 07, 2013

4L80E Cooler Lines

Confirmed that the radiator is leaking due to a crack in the plastic tank on the drivers side. New radiator ordered, and looking at what else I should replace as part of the job. The engine oil cooler lines are fine but the transmission cooler lines are leaking at all the crimps. This truck (in signature)actually has 2 trans coolers, one in the radiator and another external cooler that sites in front of the a/c condenser. So the cooler lines go from the trans to the rad, the rad to the external cooler, and then back to the trans, 3 lines altogether.

Anyone offer any pointers/advice on changing these lines? I just had a Jasper rebuilt trans installed in Sept and asked them to check the cooler lines and thought for sure they would replace them but they didn't. They did say they flushed the lines and coolers prior to installing the new trans.

Are these lines hard to get out of the transmission?

This is the line coming out of the top of the radiator, this is typical of every place hose is crimped to hard line on all 3 lines. Should I replace them or leave them?

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  • mustangglp's avatar
    mustangglp
    Explorer
    Dec 08, 2013
    Next to where I work they have a fleet of Chevy van and they all have a oil spot on the ground under the front bumper must have the same problem?
  • Heavy_Metal_Doc's avatar
    Heavy_Metal_Doc
    Explorer
    Dec 08, 2013
    I would just use replacement hose assemblies -- I would not go cutting crimps and all that hassle. They are o-ring sealed in the boss of the trans / radiator at each end.
    The plastic ring at the end of the hard line has slots in it where the retainer clip locks the tip of the hard line into place. If you have to, you can use a little pick and maybe some needle nose pliers to get the retainer clip backed out, but I prefer to use the quick release tools for these lines. You put it over the tube and push in toward the boss. It has tiny little teeth that push the clip back to allow the tube to be pulled out.
    A kit that covers all GM lines only costs about 20 bucks and is available at teh same place you will get the new hose assemblies.
    Here's a link :
    http://www.tooltopia.com/otc-tools-6611.aspx
  • BurbMan's avatar
    BurbMan
    Explorer II
    Dec 08, 2013
    Geo, thanks for the tip, I may go that route, it eliminates having to fool with them at the trans.
  • kevden's avatar
    kevden
    Explorer
    Dec 08, 2013
    GeoBoy wrote:
    BurbMan, I just installed a large transmission cooler this summer and I took a die grinder with a abrasive wheel and cut the crimps and removed the hose. the metal fittings have a barb and you can get new rubber line, 5/16, and use hose clamps to secure. Put 7500 miles on and no leaks.
    Good luck.


    I did the same thing to mine last year. I would feel much better with an adapter (are any made?) to connect some braided hose . If one of the rubber hoses fail you are stranded and will probably need a new trans.
  • GeoBoy's avatar
    GeoBoy
    Explorer
    Dec 07, 2013
    BurbMan, I just installed a large transmission cooler this summer and I took a die grinder with a abrasive wheel and cut the crimps and removed the hose. the metal fittings have a barb and you can get new rubber line, 5/16, and use hose clamps to secure. Put 7500 miles on and no leaks.
    Good luck.
  • B_O__Plenty's avatar
    B_O__Plenty
    Explorer II
    Dec 07, 2013
    Very common complaint on a lot of GM products for several years. It was easier and more profitable for GM to leave these bad crimps as they were vs. coming up with a better design that wouldn't cause problems. Falls into the same category as their fuel pumps, intake manifold leaks, alternators and so on. Change them out with a new set and expect the same failure in a few years. I USED to drive nothing but GM products..

    B.O.
  • BurbMan's avatar
    BurbMan
    Explorer II
    Dec 07, 2013
    Any info on how the line come out of the trans and whether they are hard to remove would be appreciated.

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