Chevy & GMC Vans

Ahhh, the wonderful GM leaking oil cooler lines. I have replaced so many oil lines I could easily fill the back of my astro with all of them. Many were under waranty. One of the dealerships I was at stocked about 5 pairs of each model.

The crimp is usually the problem. In a pinch you can cut off the aluminum crimp and place two hose clamps, just slightly separated, to fix the problem. You could even run it forever that way as it would probably be less likely to leak than new lines! They don't last any longer than the originals you know. I have wondered if aftermarket lines might be better, they are now available for some applications.

In the old days we did this on A/C hoses for repairs, even on the high side lines. Conversion vans still use this method on their custom made A/C hoses, and you can get replacement A/C fittings to put on the hoses at the auto parts store. For the A/C lines you can get a double clamp that has a positioning "tang" on it so you get it in the right place. You can just use two clamps though. If it works for long term (I have literally seen this last for many years) on an almost 300psi high side A/C hose containing a substance that can leak a million times easier than engine oil, it should work fine for the cooler lines.

1. Remove the Crimp.
2. Remove the hose.
3. Measure where the barbs are on the aluminum line.
4. Replace the hose back onto the line.
5. Measure to place your hose clamps on the hose in the right place.
6. Leak test and drive.

One of mine is just starting to get a bit of oil seepage and I will probably do this to solve the problem. Of course I most likely would never do this on a customer car unless it is a necessary situation. I probably won't get to it for a while (look at the in progress list on my sig).

So... Here's a quick sketch for anyone interested.

Cut on the dotted lines in the first drawing.



Do this very carefully as you don't want to cut the hose or the tubing. You need to leave the head of the crimp that the hose butts up against. Replace the missing crimp with 2 hose clamps (worm gear, band style, etc. not spring type).

You can use a cut off wheel on a die grinder, but if you do BE VERY CAREFUL. It is easiest to remove the line from the vehicle and clamp it in a vice. A dremel with a cut off wheel or hacksaw is probably the most controllable cutting tool.

As always YMMV
Hope this helps someone.

Moderators - Feel free to move to Cooling if it would be better placed there, and go ahead and sticky if you feel it's helpful enough.

Thanks DV
Mine are very bad at the moment. I will be taking it into the shop this Friday to repair them and your suggestion and illustration really helped me to decide which way to go. I will be replacing both rubber lines, but will be incorporating your ideas about the hose clamps and removing the Crimps because that's where the problem really lies anyways (In the Crimping). I can't see spending over $200.00 for something that is in perfectly good shape (Aluminum Tubings and Proper Fittings). Would you know what size and grade the hose is? I'm sure i can find out soon enough but just thought if you knew off the top of your head it would be appreciated, Thanks. Again thanks for the illustration and comments.

Unfortunately I am not sure what size the hose is. If I get a chance and am under the van working on something else in the next few days I'll pass on the size if I figure it out. I want to say it is 1/2" but that could very likely be incorrect. You do need to use oil rated high pressure hose. Standard fuel line, or even the higher pressure fuel injection hose will not cut it. Basically you need the same thing as what is used for trans cooler hose.

Let us know how it turns out as I have only done this a couple of times to customer vehicles and just as a temporary fix. I did repair the trans cooler lines on my '92 transport about 4 years ago this way and have had no problems. Like I said above... my logic says if it works for refrigerant lines that approach 300 psi and are tiny molecules compared to the boulder size molecules of engine oil I don't see why it shouldn't work.

You would think after 4 decades of using this hose crimping system and having it leak on everything from refrigerant lines, to oil and trans fluid lines, to coolant GM would have come up with a better solution. Evidently the better solution costs more to implement than the lines they have to replace under warranty. The bean counters help us again!

Just so that everyone knows... There are aftermarket cooler lines available and they aren't that expensive. For example on my '02 the lines come as a pair and are about $60. I just wanted to give other options as well, since they can leak 6mos. after putting new ones on and it's hard to spend that money again when they haven't even lost that new hose smell yet

Hi Dv
$60.00?? Do Tell please, maybe I can get something up here in after market for it. I haven't found anything yet though, and I'm not spending that kind of money ($200.00 +) on something that's been proven time again to be faulty. I will continue with what I mentioned above if I can't find anything reasonable. Thanks.

They are made by Dorman/Motormite. The P/N is 625105. I can get them locally for $60-70 depending on which parts house. One of the places is called Advance Auto Parts. You can look at their listing online through partsamerica.com. I don't know if they ship to Canada or not. Of course the price I gave is in U.S. $ so the exchange rate might make it a bit higher up there. I haven't tried any of the aftermarket cooler lines yet to see if they have better crimps that don't leak over time or not, but I doubt that they do or GM would be using the same better crimping system as the Dorman parts are cheaper than OEM even with my shop discount on the OEM.

Hope this helps Matrixx.

Thanks DV for the details, much appreciated . I will let you know what happens either way.

First the hose is 1/2" ID and I removed the old leaking flex lengths which are approx 12" long. If you have 2.5ft you have more than enough for both lengths. I use high pressure hydralic hose (has a metal sheth in it as well) other pressure lines in have seen used are AIR hose and typically redish orange. I don't recomend it since it will not like the oil or pressure at that tempurature.

Getting the colars off is the real hard part. In my AWD could not be done without damaging the aluminum pipe. I had the remove the upper coupling to cut it back and reconnect since it sprung a leak. When testing it. Give it some time and move it a bit. Their may be a bypass in the Oil filter automatically. since after we tested it. All was ok, then when done and cleaned up I was about the drive away. Oil was spraying everywhere. Right by the clamp, why did it not leak before when up in the are a nd running for minutes?? The top pipe is easy to remove once you pull the clip (careful if you loose it, it can pop and fly, the air will be blue rated!!). No room for a dremal tool or any such device. Tried that all. We used a very long drill bit and cut away at the collar but if you hit the pipe. The have to cut it back as we did later or an oil spray for sure.

Hi tripplec
Thanks for the tips as well. I have already resigned myself to the fact that I will be removing the whole unit first before modifying it. I have 2wd and I believe it's a bit easier than awd. I let you know what happens.

Matrixx, don't forget to take lots of pictures. I am pretty sure this is something I will have to do sometime, and pictures would be great.

I had the privilege of doing this job yesterday on my '99 AWD. It just hit 103,000 miles, so I guess it was time.
I was unable to remove the assembly complete, so I used my electricians BX cutters to take the top crimp off the top line as it rested on the front dif where it was hung up.
I used 1/2" Parker 200 psi hose, I hope it is oil friendly. I also used Ideal all stainless hose clamps, one turned each way, spaced like the crimps. I did notice that the pipes lacked real "barbs", having only a small flare at the end, and grooves in the middle, The lines were way easier to install in three parts. I attached the hose to the top pipes, put them in, put in the pipe that goes on the filter adapter, with new 9/16" rubber/metal seals from Advance Auto, then put the hoses on the bottom pipes. No leaks, knock on wood, cross fingers, sacrifice a virgin, etc. I did lose one clip, and had to buy an assortment for $12 at Auto Zone, ouch.

It sucked, but wasn't that bad IF they don't start leaking again.

Thanks for confirming the size Tripp.

If the leak is right at the crimp you probably don't need to replace the hose itself, just replace the crimp per se.

I don't recommend doing this with the lines still in the vehicle, cutting the crimps off successfully, especially if reusing the hose section, is kind of intricate.

If you don't want to deal with the clips at the rad connection you can simply unscrew the fitting from the rad, make sure to use 2 wrenches and it would be good to replace the o-ring then. GM says that the clips are one use only and must be replaced after removed.... you decide. I do always replace the seal washers on the newer style oil filter adapter connection. We used to replace just these as they would be the source of a leak sometimes.

Do make sure the hose you use is oil rated! Often air hose is listed as oil resistant or such but they are referring to the outer shield. Air hose will most likely not take the temps either. 1/2" trans cooler hose should work perfect. I don't know about the hydraulic hose... I would think it would be difficult to get it to seal with just the hose clamps due to the inner wire braid.

Glad to see you guys getting your hands dirty. Keep us posted.

Well It's been awhile, but did replace the Lines with the "Dorman" 625-105 unit. it cost a bit more than $60.00 up here but It was Much cheaper than OEM buy about $140.00. I paid $120.00 for the lines plus taxes at NAPA. I couldn't find it at any other place. And sorry folks for no pics, I will be taking pictures of everything I do from now on though, I have a Sony Cyber Shot so hopefully that will be good enough. The best way to remove the lines (for me Personally) was to Yank them out through the bottom. And to install the lines was to feed them through the top. It takes a bit of manipulating but I found it to be the best way, i tried from the bottom first and man that was a real pain (for me anyways) hehe. Now to clean the motor off, what a mess those lines make when they do leak.

As for my repair, I'm getting some drips on the lower connections, which were the ones I did on the van. The upper ones that I tightened off the van aren't leaking. I tightened the clamps just a little, which was all they would allow, and I'll watch them. It is a real pain to reach on the AWD, and hard to install even if you don't have them in one piece. I'm going to see if I can find different hose, the Parker stuff must not be the ticket...I dunno.

ps, I just hit 112,000