Thread: "oil" on transmission cooler line

The rubber part of the transmission cooler line seems to be very oily (or maybe describe it as oil mixed with dirty cover the rubber part of the line). And I can see the oil dirt mixture on the plastic air dam under the line. But when I checked the transmission fluid level, the level is only a tiny bit lower than the full mark so it seems I am not losing fluid(or losing very very very slowly since I am not sure whether they add transmission fluid to the full mark when I changed the fluid 5 month ago). I placed a cardboard under the car overnight and there is nothing on the cardboard. Is it normal to have a oily transmission cooler line? Maybe transmission fluid can seep slowly from the rubber or the fitting? Is it something to worry about?

The car is a 2005 Grand Prix base model. Thank you for your help!

Thank you! Exactly as you said. I think the transmission fluid is seeping from connection between the rubber and metal line. I run the car about 7-8 mile, shift to each position, place the transmission in P and then check the fluid level. The water temperature is half way in the gauge. Maybe I should run a little longer but since the outside temperature is around 60, I guess I am probably checking the fluid level properly. The line has been oily since I bought the car but I haven't seen the oil-dirt on the plastic dam under the line (Maybe I just did not pay attention.) This makes me a little worried. Well, it is good to know they can be seeping for a long time. Maybe I should run to the dealer to check.

Now, I just try to reach there and wipe off the plastic dam with paper towel to see if the oily dirt comes back. I will also put a cardboard under the car to see if there is any dripping.

I checked the parts price online. The line cost 23 and 18 each. Maybe i also need a new fitting. So your estimation of parts price is quite accurate!!

Originally Posted by Fivefingerdeathpunch

Trans fluid needs to be checked with the car running and fully up to temp.



As for the line, its very common for cooler lines to leak at the metal crimp on the rubber line, a new needs must be bought to fix the problem. Many of them are dealer only parts unless one of the local auto parts stores can get one, figure around 40-60 bucks for the part.

If its not dripping yet, I wouldnt bother fixing it, they can seep like that for a long time before it becomes an issue and a new line is needed.

By the way, do you have any idea how much labor hour would it cost to replace the cooler line? It seems like I just need to take off the plastic air dam and screw on the new line. Just wondering about the cost in case I have to replace it.

Originally Posted by Fivefingerdeathpunch

The lines actually only have a clip holding them into the radiator and the transmission, with an o-ring on the inside to make that seal.

But I think they might call for .5 to .7 hours of labor at a shop, but I'd have to look that up to be sure.

Here is a picture of how they connect.

Thanks so much! I think the seeping in my car is in the rubber-metal connection, which is just part of the line. From the connection fitting picture, it seems I only need to replace two lines and O-rings and don't need new fittings. It is great to know that the labor hour are not that high.

Originally Posted by Fivefingerdeathpunch

Trans fluid needs to be checked with the car running and fully up to temp.



As for the line, its very common for cooler lines to leak at the metal crimp on the rubber line, a new needs must be bought to fix the problem. Many of them are dealer only parts unless one of the local auto parts stores can get one, figure around 40-60 bucks for the part.

If its not dripping yet, I wouldnt bother fixing it, they can seep like that for a long time before it becomes an issue and a new line is needed.

I went to two local shops to get their opinions. The pep boy technician thinks it is leaking but it is leaking so slowly that it probably doesn't matter. He said sometimes road dirt can look like that too. He would do a pressure test to confirm the leaking (This is the first time I have heard a pressure test on transmission) but he suggested it is not worth it. I also check with a Tire Plus and the techincian said it is very common. His Chevy truck has the same thing. It is just cooler line sweating from the metal crimp. He said I don't need to worry about it unless it starts dripping. He suggest me to keep an eye on the transmission fluid level. If the level is not dropping and I did not see anything dripping under the car, just don't worry about it.