Oil line I've got a small leak in an oil line that appears to be linked to the radiator. It is located on the right side near the bottom radiator and can be easily seen from the bottom of the vehicle. It's about 7" long. My question is: I can't find it at an auto parts store, do I have to go to the dealer or can it be made using oil line and fittings? Hope my description of the location makes sense. Lenny

Get the coolant pressure tested, its definitely leaking coolant. You will need to get the coolant running line.

Pressure test will help you to know from where exactly coolant/refrigerant is getting leaked.

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For complete step by step troubleshooting i suggest you to go through the help link mentioned below :----
Click the link below: -----

COOLANT LEAK ISSUES, COOLANT LEAK PROBLEMS, COOLANT SENSOR, LOW COOLANT,
http://alltypesofpartsreplacing.blogspot.com/2012/12/coolant-leak-issues-coolant-leak.html

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These will help.
Thanks.

You are leaking transmission fluid from either the fluid cooling lines that run from transmission to a separate reservoir in the radiator, or leaking from the reservoir itself. Hopefully, it's only the lines and may just need tightening to stop the leak.
There are two lines to the radiator's reservoir. One brings fluid from transmission to the reservoir, and a return line back into the transmission. Probably located on driver's side of the radiator, one will be near top of radiator, and one near the bottom. Small copper or steel lines that may also turn into rubber lines. Clean the area well with rags to locate the leak. Will probably need to have the car running to make it leak, while looking for it. You could also take a wrench and try tightening the fittings at the radiator, and tighten any rubber hose clamps that you see. If it's not the lines or hoses that are leaking, then the radiator may need to be pulled off for repairs or replacement. But 9 times out of ten, it is a leak from one of the lines.
When fixed, don't forget to check your transmission fluid level. Or keep adding till it is fixed.

Check the bottom side of the water pump for wetness, as well as the lower radiator hose. The water pump if leaking, will run the coolant down the front of the motor,and can appear to be coming from the top of the oil pan. It is nearly impossible for the top of the oil pan to leak coolant.

Radiators with plastic top and bottom tanks have a limited life and if they leak it is usually terminal and will probably need to be replaced. Any radiator shop can pressure test your system. Replacement is not a huge job but radiators have become relatively expensive.

The passenger right side of the car doesn't have any flanges for cooling system, if that's correct then your radiator has a leak or puncture.

The driver side of vehicle has both the in and out flanges for the radiator. Very common to see leak at the drain valve leaking (not closed tightly). In the same area would be bottom flange of radiator which the composite flange is degrading and causing the leak.

The middle part of the bottom engine compartment is where your oil/coolant cooler assembly just above the oil filter. A loose oil filter could be the cause 95% of the time and 5% would be a bad o-ring from the oil cooler to the oil filter flange.

Hmm I don't recall 4.0 having oil coolers be way to be sure is to buy a coolant pressure tester fill the sytem (with water don't waste new coolant) and pressurize it. The most common coolant leaks on 4.0 engine that I see r from the rad and the water pump.

it's on the bottom of the motor, towards the back on the passenger side. It has a small clip of wires and one screw holding it on. You may want to pull it up on ramps- if it'll run- otherwise, get under the Rodeo, it's up a little higher than the oil pan, and to the passenger side. (it's right on top of the two lines that run to the bottom of the radiator.) You will need a 10mm socket to remove it. I have added a few pics showing the location (i just completed this task myself)

Most likely it is your ATF container is leaking were the two hoses on the bottom connect to it. Also there is an o-ring on the cap that can be replaced. Replace the hose clamps at the bottom with quality claps with rounded over edges. Try this part number at Bavarian Autosport, CL 16-25. Here is the BMW part number for the o-ring: 32411128333. The o-ring on the oil filter cover comes with and is replaced with the filter.

Oil leaks can come from any where. Search for information on tracer dyes on-line. If its from the radiator area and the oil appears red its transmission oil. In most cars there is an area in the radiator for cooling the transmission oil. Try replacing tightning but not over-tightning the clamps in the two small hoses connected to the radiator.