[TibetanT]

First and foremost, Markmarcela5101 you might like to start a new thread for yourself since this is someone else's posting from a few years back.

But, then again...no worries, since we all can gain some knowledge from what was said prior to your problem.

If this is all that was done, then you may have other problems!
Why? Because when the oil mixes with the coolant and then enters the engine (oil) compartment you can have problems with your bearings. Specifically, your Rod Bearings.

So, what you can/should do now is as follows: (Just my opinion)
1) drain your oil
2) drain your coolant completely
3) put a small amount of detergent inside your coolant system and fill with water so you can flush all the oil out of the coolant system. I do this with the bottom hose off so I can watch it drain which helps.
4) you can run a hose with clean water through for awhile, to ensure all the oil is cleaned out and the soap is gone too.

Next, fill with proper coolant (use the type that is okay for aluminum radiators).
Remove the oil filter, and replace with a new Mahle Oil filter (purchase here on Pelican Parts).
Fill with the proper oil grade for your area.

As above stated by member DJNOLOAN...make sure you replace the crush washer on the OPRV and tighten to specifications.

After the coolant system is filled with proper coolant, run the car with the heater on full blast and burp the system. In other words, run the car and remove the air from the coolant system as noted in the Factory Manuals (if you have them), Clarks Garage website, or Haynes Manual for the 944.

Hope this helps and keep us posted on your progress.

Good luck!