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Oil cooler lines leaking.

Discussion in 'Chevy Trucks' started by 70monte, Dec 17, 2008.

  1. 70monte

    70monte Senior Member
    Messages: 468

    It appears that the oil cooler lines are leaking on my 98 K3500 with the 7.4L. Has anyone had to replace these and if so, how hard of a job is it? Is there anything to watch out for or any tricks to making this repair easier? Does anyone have the GM part# for these lines?

    My power steering cooler lines also run down next to the oil cooler lines so it may be those instead or also. All of these lines are an oily mess and now something is dripping on the carport. It looks like motor oil but I'm not sure. If these are the problem, how hard are they to replace and anyone know the part# for them? Thanks for any help.

    Wayne
     
  2. Spitz

    Spitz Senior Member
    Messages: 192

    Engine oil cooler lines? Trans cooler lines? I know the engine oil cooler lines have always been a replacement part, they leak where teh ferrules are crimped.
     
  3. mercmn91

    mercmn91 Junior Member
    Messages: 11

    I replaced tranny cooler lines in a 95 tahoe with 350. Don't know the part no. but they were not too bad to do. Not that hard at all.
     
  4. MAR4CARS

    MAR4CARS Senior Member
    Messages: 246

    Those engine cooler lines always leak. While replacing those look at the oil filter adapter thats probably leaking as well . the lines attach to the radiator with fittings make sure the new lines have the o rings on them no need to use Teflon tape as the threads do not seal only the o ring does.on the engine side the lines snap into couplers i would replace these couplers as then tend to leak as well.The filter housing is held on by 2 long bolts theres a seal/gasket kit available for the housing.I know the couplers and housing gasket kit is available aftermaket the lines i've always gotten at the dealer and never checked to see if they are available aftermarket.
     
  5. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    My truck has a factory oil cooler from a '91 Sub on it, lines were discontinued. No aftermarket sources either. Took my old lines to a hydraulics shop and had them replace the rubber sections (they were leaking at the crimp), reusing the remainder of the tubing and fittings. No leaks, very reasonably priced. If the replacements are expensive, look into what I did.
     
  6. Spitz

    Spitz Senior Member
    Messages: 192

    Yea, you should be able to cut the ferrules off and even use hose clamps if your in a pinch.. Ps- some tranny lines dont come fabricated, most times we end up making ours out of bulk brake line.
     
  7. Clint S

    Clint S Senior Member
    Messages: 280

    You want to know what my dealer said after my oil cooler lines leaked at 2 years and 18k..... " A little seepage is normal". So I said If you can show me 1 new truck on the lot that has "a little seepage" after we drive it I would be satisfied and not get the repair. They replaced the lines. Guess what they leaked again less than 1 yr later they replaced and now my 3rd set leaked too. I just live with it it is not that much.
     
  8. 70monte

    70monte Senior Member
    Messages: 468

    The oil cooler lines on my 98 K1500 leaked when it was still under warrenty and the dealer replaced them. The ones on the K3500 look like they are leaking pretty bad. There doesn't appear to be any oil leaking from the adapter where the oil filter screws onto but I will have to look closer to be sure.

    Wayne
     
  9. dirtmandan2

    dirtmandan2 Senior Member
    Messages: 275

    I replaced the lower oil cooler line on my chevy today. Got the parts from carquest. the line was about $28 and the new quick disconnect around $8 . The job wasnt terrible, took a couple hours, I removed the oil filter and was just able to get the 1" wrench on it.
     
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Stay away from the GM cooler lines Wayne. They're still scrap and have been for a long time. Dorman makes good quality aftermarket replacements for your specific truck. Run you around $70 or so for the pair.

    Their a little tougher to swap out on the 7.4's but with a little finesse they'll come out. Be gentle with the fittings and O-rings and be positively sure that the retainer clips are fully engaged...otherwise its relatively straight forward.
     
  11. Spitz

    Spitz Senior Member
    Messages: 192

    On the s10 blazers you have to lift the engine slightly for them to clear on some, not much, just have to stretch the engine mount a tad.
     
  12. 70monte

    70monte Senior Member
    Messages: 468

    Thanks for the input. I will go with the Dorman replacements. I'm going to try to wait for a warmer day to tackle this job in case the repair goes longer than anticipated as is usually the case. I assume the new lines come with the new O-rings and clips?

    Wayne
     
  13. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Sure do. At least their supposed to. Have gotten a couple that were missing the retainer clips so be sure to open the box and check before you start.
     
  14. 70monte

    70monte Senior Member
    Messages: 468

    Ok thanks. I picked up the cooler lines today. I went with the Dorman replacements. $60 for both from Carquest. They came in a long plastic bag and the retainers and O rings are there.

    A couple of people have mentioned replacing couplers and quick disconnects during this repair job. Where exactly are these and are they necessary to replace? If the oil filter housing gasket is not leaking, should I just leave it alone or should I also replace it? Thanks again.

    Wayne
     
  15. Clint S

    Clint S Senior Member
    Messages: 280

    http://www.s10forum.com/forum/f107/repair-your-leaking-oil-cooler-lines-343472/

    Here is a way to repair you lines it is on an S 10 but they are similar I think. I do not know if I would do it except if I was in a pinch though.
    Edit This is for the remote filter lines not the cooler lines.
    I would replace the coupler a disconnects too. Just had it done on the HD, but for the tranny lines. Was the best $100 I spent having a shop do it though.
     
    Last edited: Dec 22, 2008
  16. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The quick coupler disconnects are how the lines are attached at each end. Your new lines came with new clips and O-rings which will basically re-new the coupler connections. No need to replace the coupler fittings themselves as they aren't normally an issue on the engine cooler plumbing like they can be on the auto trans cooler plumbing.

    Installing a fresh gasket and O-ring under the oil filter sandwich adapter is a good idea though.
     
  17. 70monte

    70monte Senior Member
    Messages: 468

    Years ago I had a 93 S-10 4x4 with the 4.3L and the remote oil filter that developed leaks on the remote filter lines. I bought new lines to replace them but when I went to remove them, I couldn't get them off because there was too much stuff in the way. I never replaced them and soon after traded the truck off.

    Wayne
     
  18. 70monte

    70monte Senior Member
    Messages: 468

    I just got done looking at the new lines. The ends that go into the oil filter adapter do not have O-rings but has a metal collar on the line. The ends that go into the radiator have O-rings and the threaded fitting. Are you saying that on the radiator side, where the line screws into the radiator, that this is a quick coupler disconnect?

    Since there are not any O-rings on the oil filter adapter end, what keeps this end of the line from leaking? The metal collar that is on the line at this end doesn't look like it has any rubber in it or anything to create a seal.

    Since its been so cold out and I don't have anywhere warm to work on the truck, I haven't looked at the area where the lines hook into the filter adapter. I just want to make sure I have everything before I start this job. I will replace the gasket and O-ring under the oil filter adapter just to be safe. Thanks again.

    Wayne
     
  19. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The fittings at the oil filter adapter end have Viton seals made internal so there's won't be a seal on that end of the line. The radiator ends are O-ring like you described.

    If you desire to replace the filter adapter end fittings (just as preventative measure, although I only do if they previously leaked) make sure you use ONLY genuine GM fittings as the aftermarket fittings are garbage. IIRC the GM p/n for the fitting is 15043741 but be sure to double check as there's two different fittings used in that location throughout the years.
     
  20. 70monte

    70monte Senior Member
    Messages: 468

    B&B, thanks for the info. When it warms up I will check to see if there is anything leaking at the filter adapter end.

    Wayne