I am hoping to get advice and a diagram link from someone like scottjh9, but if you have experience with the STR coolant lines, That’s works too.

I have a leak in one of the coolant lines.

It looks like oil to me, coming from what I believe to be an oil line of some sort.



Removed the air intake system, now you are looking down into the drivers side of the engine compartment. Visible are several hydraulic lines. Two I believe to be transmission coolant lines, others seem to be oil lines.

Zooming in, fluid is visible looking around the bolt.

Dipping a paper towel into the fluid, you get this.


Dealership told me I had a transmission coolant line leak. Sure looks like the bigger darker hydraulic line is an oils line and leaking oil to me.

Any diagrams out there than I can use to identify what I am looking at so I can better diagnose the leak?

If it’s oil, then I can keep an eye on oil levels until I can get it fixed. Not a crisis really.
If it’s a trans cooling line, I can’t do anything to check trans fluid levels or top it off. So the regular loss of transmission fluid would make this a very high priority repair.

Questions or thoughts are welcome, and thank you in advance!

 

hi
where that is looks like engine oil cooler lines
trans oil cooler is built into the r/h side of the radiator, under the maf/air box area
2002-2005 have one oil cooler in the middle, 2005 onwards have one each side
its hard to tell really from the pics, but trans oil is a light brown/clear, looks more like engine oil
can you not tell by the smell of it

oil cooler and lines

 

I have a 2005 STR so it's a bit different. There are some threads out there on repairs to the tranny cooler lines WO replacing them. A couple of them. Good pictures too. Get searching!
IMHO the original design is flawed in that it doesn't have enough flexible hose near the connection to the top of the radiator and so the engine movement eventually causes the the swedged fittings to weep.
The fix involves cutting the metal tubes on the radiator side and inserting much more hose. Compression fittings are used to connect to the metal tubing stubs at a strategic spot so that future access is easiest. A miniature pipe cutter can be put on those tubes and rotated in place. This has worked like a champ for me. Much better than replacing the entire assemblies.

OTOH I also had the same exact issue with the engine oil cooler hoses, both at the same time! Those I decided were too difficult to modify reliably. I have a dual oil cooler set up unlike your single one. So I put new OEM one's in.

 

The easiest way to pinpoint the leak is put the car on ramps or jackstands, pull the underbelly tray off and look with the car running....make sure you start off with a cold engine because some leaks go away as the engine warms up.....as Joe said, the oem tranny fluid is brown in color like fresh engine oil, so a color diagnosis is not the best bet.....i have done my trans lines, but as statsoff said, the oil cooler lines are a different animal.....once you get the leak identified, we can help .....yes it is imperative to find out because of the trans fluid check and fill procedure in case it is tranny fluid ...the zf trans is finicky about being low on fluid

 

Thanks for the responses guys.

A little backstory, not too long ago I replaced the pulley on the AC compressor. It was a long thread with pictures and the use of inspection camera. Everything with that worked out fine, but I kept having this nagging feeling in the back of my mind. I didn’t like jacking up the engine that little bit needed to swap the pulley because I thought it might’ve put some pressure on the oil pan when I did it.

When I started seeing a little drops under the car, they looked like oil. So I assumed that I had done some damage to the oil pan gasket.

This wasn’t a hard fix, and she was due for an oil change anyway. So just a couple days ago I changed the oil pan gasket along with the oil.

The old gasket seemed fine to me when I took it off, but I still replaced it anyway.

I cleaned everything up underneath there and ran the car cold to see if I had oil pan leak. To my dismay the leak was actually coming from the area of the transmission and oil lines as they ascended.

Good news is, no oil pan leak LOL.

As I had just replaced the oil, I assumed that the light brown fluid I was seeing was new oil, therefore I assumed the leak was in an oil line.

After talking with you guys and doing some more research, I’m really beginning to think it’s actually transmission fluid. I’ve also noticed the transmission shifting just a little funny over time and it seems to be getting a little worse as I let things go on.

I am making the assumption that replacing the transmission lines because of an apparent leak is the best course of action.

In the interim I began checking the oil level after the car sits all day while I’m at work. I’ve will be taking pictures of the dipstick, with the first check happening today.

So while I’m looking into replacing the transmission lines, I’ll keep an eye on the oil level too. If I notice the oil is dropping after several days, perhaps we can rethink things.

Meanwhile I found those connections and hydraulic lines linked above and I am feeling that those would probably work.

Thoughts?

 

At the very least, get to a trans shop or an everything shop that knows the transmission fluid check procedure if you have the chance so as to not damage the transmission valve body and internals

 

This leak reminded me of a video I watched a little while ago. In this video a 2003 STR just like mine was taken in for a transmission service across the pond.

Pretty neat video:

You Tube

Points to consider from this:

1. After initial inspection I see no leaks coming from the pan and no visible fluid along the transmission cross member. I will do a more thorough inspection this weekend to include the TCM. So unless the TCM is leaking I see no reason to drop the pan.
2. The filling procedure is to fill it it until it runs out, wait for the drip to stop, run the engine until the trans reaches 40deg C, fill until it runs out, let it run out until it just stops and replace the filler plug.

To be honest; with my workshop, the repair manual, the right parts and an afternoon... I’m confident I could replace the pan, TCM seal and fill the transmission on a Saturday if needed.

My experience with mechanics in my area has not been good, leaving me with the notion that its up to me to become my own “Jaguar Fixer” unless the job exceeds the abilities of my little shop. If I can’t do it, I then move the car literally an hour away into the countryside to the one mechanic I have confidence in. If he can’t do it, I cry and begin putting the car into the hands of the dealership (who are actually terrible, immensely overpriced and take forever).

So... most repairs I conquer screaming,

“YOU! SHALL NOT PASS!!!”

Anyway, off my soap box...



As of right now, it seems reasonable that the prudent course of action would be to top off the trans fluid (with the correct fluid of course). The thing to work out is getting the car both elevated and level so the fill is right. This I can also do.

When topping off, if fluid almost immediately runs out, then the fluid level was good. If it takes more fluid, this reinforces the trans line leak hypothesis. This would in turn be the que to go ahead with the line replacement as discussed in other threads.

Wouldn’t You agree?

This then leads to my question for those who have more hydraulic line experience:

What are your thoughts on the items linked in my earlier post?

(Thanks again for the responses, I do Love a sounding board

 

why does the pan need to be replaced vs just the pan gasket?

I usually smell the fluid as engine oil and trans fluid smell completely different

I have a leak too but mine looks like its at the connection to the radiator cooling fitting. I believe theres an oring seal in there so I will replace that this week end and figure out how to top off the fluid.

 

On the ZF transmssion the pan is made of plastic and also contains a built-in filter that is not available separately...

If I recall correctly, the A/T sump bolts are made of aluminum and also should be replaced at servicing; reportedly they can also be real buggers to get loose from the transmission housing.

 

Sounds like a good plan.....after you get the car raised, make sure you can get the fill plug loose.....they are usually very tight ...i cut back the allen wrench for the plug so it would fit and use a cheater pipe on the other end for leverage....it also makes it easier to have a helper monitoring the trans temp so you can stay under the car

 

Bolts are not aluminum and usually come with the pan/filter kit. Original bolts have too small of a drive socket. There are great after market pan/filter kits.

Find my thread on this as I made a neat fluid filler tool out of an orange juice jug with fittings for compressed air NOT OVER 2 PSI. Makes it a lot less messy. I used an IR laser to measure the temp.
You should replace that sleeve at the same time. That I did a bunch of swearing at though.

 

Wow, i have an ir temp gun and did not think of it.....oh well next time.....chalk it up to experience

 

My trans cooling lines were leaking. It's a common problem... check out my post -> https://www.jaguarforums.com/forum/s...h-tips-215808/

 

So after thinking this through and doing more research, I believe this is the plan for the transmission.

1. Stop the leak and get fluid levels right. I have ordered the parts and have set aside this weekend to replace the leaking hydraulic cooling line (replacing both actually).
2. On the docket for the near future goes a transmission service. This includes: New pan/bolts, new sleeve, new solenoids, new gaskets (bridge seal, tube seals) new foam filter and new fluid.

This, except on the 6HP26 instead of the 6HP21 shown in this BMW.


I will update when I make the coolant line repair, should be this weekend.

 

So after another few hours working in the incredibly difficult to reach area between the idler pulley and the radiator (which I will now call “the void”), I was able to splice in a new section of flexible line for the transmission coolant. As I was on ramps, I floated the rear of the car up and leveled things. Spent an hour with a torch and a hacksaw to cut down an Allen wrench, torched the drain plug for 30 seconds as suggested, and got that Mo&%^<£ Fu&$@^% drain plug out. So tight!



Followed fill procedure.



Chased a few very tiny leaks, cleaned everything up, laid a bed of Pristine paper towels under the front of the car, placed a small section of clean paper towel directly under the splice (within the void lol) and started the car.



25min later she was at 45-50c on the pan and pristine clean paper towels. I only had time to put the car back together and move it to a parking spot. There didn’t seem to be a leak but I couldn’t test drive it. No time and a blizzard left a foot of snow on the ground on that very day. So I have to wait.



About a week later…



After driving the car for a while and checking for any leaks, it appears that everything has worked beautifully. No transmission leak is apparent upon inspection, so I’m calling this a win!

Great write ups referenced one this thread, and a really good one with the technique and parts I used here:

https://www.jaguarforums.com/forum/s...6/#post2169577

If you have a leaking transmission coolant line, you can fix it!