I noticed a transmission fluid leak on the fron passenger side of my car. It seems to be coming from the oil line going from the radiator to the transmission oil cooler. I hope it is not the return line since I would have ordered the wrong part. I have a couple of questions:
- why is the transmission oil line going first into the side of the radiator and then into a seperate cooler?
- It looks like I will have to remove the upper main water hose to get to the line. Does the engine cooling system have a drain somewhere? I would probably have coolant all over my garage just opening the hose...
- When tightening the hose back up to the oil cooler and especially the radiator, how easy is it to brake the plastic fitting on the radiator? I can just imagine the cost of that puppy. Any special trick or procedure? How tight does it need to be?
Thanks,
Sab. <img src="graemlins/yltype.gif" border="0" alt="[typing]" />

 

Never mind about the cooling hose. Got it off already.
Looks like the housing for the two electric fans has to come off in order for me to get to the nut of the oil line. This seems to be more involved as I initially thought (as always).
Quite a huge nut there. 30mm? I guess I'll be going to Home Depot.
regards,
Sab. <img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

 

Hi,

Been there done that...Don't know why it runs up the side of the rad other than to make it "easier" to get the fluid up to the top...and provides some temp equalization...

There is a coolant drain on the bottom of the rad, but don't know how successful you will be draining some and putting the plug back in...

You will need to remove the upper rad hose. It is a real B#$#@# to get at that upper line for sure.

You will need to counter hold it as I remember having to hold one nut on the rad and then turn the tranny cooler nut being very careful not to strip the one in the rad.

Much easier if you can remove the cooling fans (on an S4) but that is a pain in itself.

I was able to snug it up just tight enough, but watch it for a few days after you do it. Also, disconnect the battery as you will be working really close to the jumper terminals and if you slip.....sparks everywhere..

<img src="graemlins/oops.gif" border="0" alt="[oops]" />

Don't forget to check the tranny fluid level once you are finished and top up if necessary..

Good Luck
Tom
midlman@seanet.com 87S4 AT
[quote]Originally posted by Sab:
<strong>I noticed a transmission fluid leak on the fron passenger side of my car. It seems to be coming from the oil line going from the radiator to the transmission oil cooler. I hope it is not the return line since I would have ordered the wrong part. I have a couple of questions:
- why is the transmission oil line going first into the side of the radiator and then into a seperate cooler?
- It looks like I will have to remove the upper main water hose to get to the line. Does the engine cooling system have a drain somewhere? I would probably have coolant all over my garage just opening the hose...
- When tightening the hose back up to the oil cooler and especially the radiator, how easy is it to brake the plastic fitting on the radiator? I can just imagine the cost of that puppy. Any special trick or procedure? How tight does it need to be?
Thanks,
Sab. <img src="graemlins/yltype.gif" border="0" alt="[typing]" /> </strong><hr></blockquote>

 

The radiator has an internal transmission fluid water cooler within the radiator. Once cooled it’s pumped to the air transmission fluid cooler, than back into the transmission. The two coolers are connected in series.


Use two wrenches when removing any line or pressure hose, one to pull the other to hold

Steve C
The Great White
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

Easier said then done...
It just won't come loose (the large nut on the radiator)!
regards,
Sab. <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />

 

Don’t turn the radiator nut, hold it; turn the line nut.



Steve C
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

I finally got it off and the new one back in. Just have to tighten it all up now and put the fans back in place. What a piece of work to get that little hose in there...
Thanks for your help Steve.
regards,
Sab. <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

 

Steve, or anyone else,

I noticed that one of my trans cooling lines at a point roughly below the passenger coil, has a factory bend in it on the metal part. That bend appears to have a slight crease, which in my opinion could limit flow to thru the line. It looks like a factory bend, but I'm wondering if this is normal for that hose. I considered replacing it, but am not sure if the new one would also have the crease at the bend.

Anyone else notice this?
Greg

 

Hello Greg,

I beleive you are referring to the exact hose I just changed. I am not sure what you mean by "crease" (it's my poor technical english... in German I would probably know...), that hose makes a pretty sharp 180 degree turn coming out of the back or the radiator going to the tranny oil cooler. Its a sharp but smooth bend. If that is the hose you are questioning, I can send you a picture of my old one.
cheers,
Sab. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

Hi Sab,

I just looked at my line again. It's not the one you did. Sorry for the confusion. I posted before from memory of the line's location (bad idea).

The car has to be jacked up to see it. My line in question is the lower radiator line and the crease is in the line almost exactly where it passes the air cond. compressor along the body of the car on it's way to the trans. There is a shallow turn there, but the more I look at it, the more abnormal it appears. Almost like something hit it.

I'm chasing a trans problem and will be doing pressure checks this week, I would not want a restrictive line to cause incorrect pressure readings.

Thanks for your help. How's the other stuff with your engine shop going?

Greg

 

Greg,
The fluid from the radiator is not control fluid, its lube and cooled trans fluid. It will not affect working pressure.
BTW, you should change the modulator, the diaphragm fail with age. M. B dealer, tell them the color of the modulator. If the line is crimped, change it.

Steve C
The Great White
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

 

Hi Steve, I'm going to add to my slipping trhread when the pressure gauge I ordered comes in this week and I can post pressures. I have re-chcked vacuum, modulator leakage and TV cable adjustment. I figured pressures would help you assit me more than anything so I can't wait to fill you in.

I'll get a modulator in the mean time. Funny you mention it, I have been thinking of replacing the modulator as a preventative measure. You have convinced me. Also, I will look into replacing the crimped line.

Greg