Looking for some help. I have 2000 Chevy Monte Carlo SS with the 3.8 liter V6 Series II engine.

For a little history this car has about 180,000 miles. I bought the car as a project for 16 year old son. I had the water pump fail and leaking coolant on the ground so I installed a new water pump on and the car worked perfectly for about a month. One day the check coolant level light came on and when I opened the radiator cap I discovered a significant amount of frothy oil in the radiator. No other symptoms.

I proceed to replace both the upper and lower intake gaskets and used the metal gaskets on the lower and replaced the power steering pump and belt tension idler arm and coolant tubes. I also put on a new plenum and replaced the old vacuum line that started to crack.. I flushed the coolant six times and used blue devil flush to help remove any oil. Note: the oil pressure would also increase when increasing acceleration to about 3/4th from 1/2 on the oil pressure gage. For ****s and grins I also used the Blue Devil head gasket sealer using the amount recommended by Blue Devil. The frothy oil in radiator reappeared during the test drive so I took it to the shop.

The shop flushed the coolant system and they thought that maybe it was just old oil in the coolant from the prior leak as it remain clear after flushing for long period with Dawn dish soap. They kept the vehicle in the shop over the weekend and they they discovered a small amount of raw oil in the radiator which he showed me. The mechanic has a lot of experience with the GM 3.8 and said the he did not believe it was the head gasket as there is no coolant in the oil and no compression loss. He said the only way for this to happen is at the oil adapter gasket, timing chain cover gasket or the rear main cover gasket. He gave me an estimate of $1000 to replace the timing chain gasket and $2000 to replace the rear engine cover gasket. This engine does not have an oil cooler. He could not guarantee that it would fix the problem but knew I am pretty handy and that I could do these repairs myself as I only paid $3,000 for the car. He suggest to first try changing the oil adapter gasket as the first step.

I then proceeded to replaced the oil filter adapter gasket, installed a new oil pressure sensor and flushed the coolant system but the frothy oil has returned upon the test drive. The engine still purrs but the oil pressure fluctuates as described previously. Also still no coolant in the oil.

My next step is to change the timing cover gasket as i can do this without removing the transmission.

My question to the group is, is there other things i can try before removing the timing chain cover and install a new timing chain gasket? Anything I should go back and double check? I have enough head gasket sealer to repeat this but doubt that it will help.

Thanks in advance for any suggestions.