M1009 Oil Cooler Lines And Leaks

[RickTheEngineer]

Hello everyone, hope all is well. Got a question regarding the stock TH400 oil cooler lines on my M1009. I am getting down to where my transmission is leaking (losing 500ml per 3-4 weeks). I think that my oil cooler lines are suspect. The reason why I say this is because I am seeing some wetness near the driver side wheel well on the frame as well as wetness on the hose where the steel fitting is on the rubber hose in that area. (This line leads into the radiator, so I'd imagine this is the oil cooler line?) I found some part numbers (NAPA)... BK 8232229 (upper) BK 8232235 (lower). Here is what I don't get though, these lines aren't the kind that go all the way to the radiator are they? Or are there more lines that I need to buy to do a complete repair? Most of the trans oil that is leaking can be found on the passenger side frame kind of close to the starter. Any thoughts? Or part numbers? I apologize for my lack of knowledge on the topic. (The year is 1985 by the way!)

 

[Barrman]

There are two different coolers in the radiator. The solid metal lines for the transmission on the passenger side and the rubber/aluminum lines from the back of the engine up the drivers side inner fender and across the radiator for the engine oil cooler.

Onviously, one leaks red and the other leaks black. What do you have?

 

[RickTheEngineer]

Oh man! I had no idea! That might explain why the parts that I looked up never matched up haha... But I think the engine oil cooler line might have a small leak then, because the wetness is hard to identify the color since the leak is pretty slow overall, but it is enough to make a drip, but undoubtedly I am losing tranny fluid on the passenger side, and by a significant amount too. I didn't see wetness on the portion of the tranny cooler line that connects to the radiator per se, but its mostly hidden under the truck. Do we need pics?

 

[GM72K10]

http://www.plews-edelmann.com/assets/1/7/coolerlines_tl-003.pdf

These guys have most everything either way. Transcooler lines are part number CTT-8146

 

[RickTheEngineer]

Hello all, I know I am returning to an older thread, but I don't want to spam up the CUCV forum with the same problem until at the least I uncover more details on the problem I am having. I have had a few problems come up that I had to take care of leaving me without much time to work on the CUCV. Here is what I found. Tranny cooler lines are soaked there the bellhousing area is and where it mates to the engine. Starter is wet, the the passenger leaf spring is wet too. It is actually running down the chassis almost to the rear axle. The lines don't seem rusty or anything and I seriously wonder if they are actually the problem. Do you all think that could be it? Dipstick tube is clean. I just cant imagine any seals that would go bad that would cause the fluid to travel where it has been going. Is it a high pressure line or something? Because if it is, I feel like its almost "spraying" if you will. Not sure though.

 

[Christianfishn]

are you loosing oil at all? if your oil levelseems to be decreasing check the oil cooler line which runs from the passenger side side near the oil filter forward near the fender then into the radiator. the line is known for problems. The line transitions from hard line to rubber and the junction there is known for leaking, i had to repair mine.

As for the loss of ATF fluid i am not endirely sure what would fling fluid as youndescribe from that location.

 

[RickTheEngineer]

I should have clarified on the title that I meant ATF cooler line, but yup, that's what I am losing. I will see if I can post a pic up on what it looks like, because I am a little confused not gonna lie. Its soaking the bell housing, but I don't think its a seal. Plus the passenger spring is wet so Im a little confused.

 

[cucvrus]

I am thinking maybe the cup seal that the transmission dipstick fits into. Easy fix.

 

[RickTheEngineer]

Here are some pics to help the cause!

 

[CUCVM1009]

The best way to find the leak:

Wash all the dirt, grease and lubricant away. Take a good cleaning solvent. (I am using "motorcycle-cleaner")
Let the truck time for drying.
Then drive a few miles, and watch where it´s come from!

Good luck!

 

[cucvrus]

Here are some pics to help the cause!

It seems you have many of the normal leaks on a 30 + year old truck. The transfer case is leaking at the shifter seal. The transmission is leaking at the 4 bolt governor cover and the pan gasket. I think you may have a rear main seal leaking on the engine. These are all normal issues with a vehicle of this vintage. All are repairable. The most difficult because of access will be the shift linkage to the transfer case. I have removed my transfer cases and sent them to a transmission shop for new seals on occasion. But only if they annoyed me and I was unable to stop the leaking. The rear main seal is real straight forward and a very dirty messy job. As soon s you fix them leaks I am sure others will start somewhere else. General Motors rust proofing system.

 

[Hennek]

I'm sorry for replying to an old thread but I'd rather continue here than ask for help elsewhere. I would like help clarifying what Barrman had said about the metal trans cooler lines being on the passenger side and and rubber/metal lines on the driver's side are engine oil. From what I gathered from the TM, I'm seeing it as the opposite. Am I reading the TM wrong on this one? I've attached some pics of what the manual says and I've attached photos of the vehicle. The metal lines are definitely on the passenger side as are the rubber/metal lines are on the driver's side, I just want to know what lines contain what fluid. I guess I'd find out when removing the lines anyways but im happy to take advice beforehand! I plan on installing a fan-less trans cooler I recently got to help with my occasional towing trips. I know there are other threads for that as well which I have read through. But if it doesn't get anyone in trouble and they have any advice on that project I'd also be happy to hear it. Thanks in advance.

 

[nyoffroad]

In your top pic on the left hand side is 2 rubber lines that screw into 2 aluminum lines, those are the engine oil cooler lines and they go across the radiator to the passenger side. If you decide to replace them be careful as the steel to aluminum causes corrosion and it's not hard to rip the threads out of the al. nut.

 

[Hennek]

In your top pic on the left hand side is 2 rubber lines that screw into 2 aluminum lines, those are the engine oil cooler lines and they go across the radiator to the passenger side. If you decide to replace them be careful as the steel to aluminum causes corrosion and it's not hard to rip the threads out of the al. nut.

Thanks for getting back to me on this. It was late last night when I was working and after reading your post I had some clarity. The top pic with the rubber to metal lines run across the radiator like you said and the pictures taken on the right side of the vehicle are of the same lines, is just where they thread into the cooler/radiator housing. I believe I found the transmission cooler lines. They are on the left side as the manual says, they are above and below the rubber/metal lines as seen in that top photo. I don't plan on touching the engine oil lines until I absolutely have to. I know they leak a bit around the fitting but I'm going to let it rest for now. My goal is to only have to modify one of the trans lines to install that cooler. Thank you again

 

[StantheLawMan]

Sorry to reply to an old thread--I am looking to purchase a replacement oil cooler for my M1009. My lines are fine and do not leak. Is there a "go to" replacement or do any of you have any suggestions for the best product. I do have a newly installed Banks Turbo Kit (that I managed to get together and it works fantastic), so I want to make sure that my oil is sufficiently cooled as I know the turbo adds some heat in this respect. Thanks in advance for your response.

 

[Sharecropper]

The OEM oil cooler is housed in the passenger side of the OEM radiator, so in order to "replace" it you would have to replace the entire radiator. I believe what you may be thinking of is to add an auxiliary oil cooler to work in conjunction with the OEM cooler. There are many threads on SS regarding these, so please search. I'm sure you will find what you need with responses from other SS members.