Oil leak from the oil cooler sensor

There are several possible sources for an oil leak in a vehicle. Some common sources of oil leaks include:
Oil pan gasket: The oil pan gasket seals the oil pan to the engine block. If the gasket becomes worn or damaged, it can allow oil to leak out.
Valve cover gasket: The valve cover gasket seals the top of the engine and helps prevent oil from leaking out. If the gasket becomes worn or damaged, it can allow oil to leak out.
Oil filter adapter: The oil filter adapter connects the oil filter to the engine block. If the adapter gasket becomes worn or damaged, it can allow oil to leak out.
Oil cooler lines: If your vehicle has an oil cooler, the oil cooler lines can develop leaks over time.
Engine oil cooler hose: The engine oil cooler hose connects the oil cooler to the engine. If the hose becomes damaged or develops a leak, it can allow oil to escape.
To determine the source of the oil leak, it will be necessary to visually inspect the engine and related components. It may also be helpful to use a dye or UV light to help identify the source of the leak. If you are unable to locate the source of the leak or are not comfortable attempting to fix it yourself, it is recommended to have the vehicle inspected by a professional mechanic.

Bingo correct when engine gets a few miles up the seals go hard.Allows oil to seep into water.Bad design.Barinas.Astras.Have fun.

i had the same problem and it was a cracked oil cooler and all i done was by pass the oil cooler take one hose off the lower radiator hose and the hose take off the oil cooler and the one off the oil cooler put it back on th lower radiator hose and the one that u took off the lower radiator put it back on the oil cooleer

that's because it's easy. it's like a radiator, disconnect hoses, replace unit, re-connect hoses

INSTALL OIL COOLER
-clean the oil cooler contact surface on the oil cooled mounting
-install a new O-ring to the oil cooler.
-temporarily install the oil cooler with the nut
-apply a light coat of engine oi on the threads and under the head of the relief vale
-install the plate washer and union bolt. torque 78Nm (800kgfcm, 58 ft lbs.)
-tighten the nut,torque 8.8Nm (90kgfcm, 78 inch lbs.)
-connect the 2 water bypass hoses to the oil cooler.

HOPE THIS CAN HELP.

There is a very easy way to check the oil cooler for leaks.

Do this with the engine cool and be prepared to catch some coolant in a pan.

Remove the 2 coolant hoses from the oil cooler and attach them together using a 5/8 inch straight heater hose connector. You are bypassing the oil cooler temporarily. Wipe the oil cooler clean so you can clearly see any leaks develop.

Now run the engine and watch the oil cooler pipes (the ones you just removed the hoses from) carefully. If you begin to see oil seeping from the cooler pipes you've found your problem.

This might take a while to see so be patient and let the car run for at least 15 mins or more.

Don't worry about the cooler being disconnected while the car is running, but I do recommend reconnecting the cooler if you have to drive it even if you find it to be leaking.

If it is found to be leaking, you will need to replace the part and have your coolant flushed out properly to remove as much of the oil as possible from the system. Also change the engine oil at the same time, it is possible that coolant has gotten into the oil although it may not be obvious.

Good luck.

Oil cooler lines that lead to your radiator or to a cooler mounted in front of radiator.The hoses are quick couplers with o-rings so there is no way to tighten. I don't know why they would leek so often but they usualy go bad where the rubber line gets crimped to the steel line.Not sure if you can get a different oil filter block without the oil cooler line hook ups.This way you can eliminate the cooler lines,or remove the quick couplers at both ends of where your cooler lines hook up and just run hydraulic hoses in place of your coller lines.Where i live you can get hydraulic hoses made at hundreds of places but may not be so redily avalible where you are.

its more than likely either your head gasket or intake gasket. You either have the 3.4 or 3.8 engine and they are well known for these to leak.

It does sound like an engine oil cooler failure. The cooler on this is the big lump of metal under the oil filter housing. It fits down into the block and has several hoses and sensors. The normal way to check for a leak is to pull it out and pressure test it. You may however be able to drain your coolant, then look for a short piece of hose between your oil cooler and EGR cooler. This hose will twist about 90Deg and then you can slide it back toward the EGR cooler. Make sure you have plenty of engine oil and start the engine with this hose off. If you have a bad enough oil leak the oil may be pumped out here. This may also be a craked head or a front cover problem, but most of the time those will put coolant in the oil.