I am driving a 1996 4 dr. Chev Lumina with the 3.1L V6 and only 70k miles. The markings on the engine say 3100 SFI. I had noticed it was loosing coolant and at times running a little warm. I would add coolant and it would be okay. Then I checked the oil and it was down 1/2 qt. so I added 1/2 qt, I notice on the filler cap a light brown sludge that looked like chocolate mayonase. I have read many with the GM 3.1 V6 have had a problem with the intake manifold warping and allowing water anf oil to mix causing sludge. Is that the correct statement of the problem with these V6's? I also understand that Dorman had a 'solution' to fix these engines. It was an imprvoed gasket kit, I believe. I bought the Haynes Repair manual for this year and have been reading it to see if I want to do this procedure. I have some questions: Do you need to first remove the alternator to remove the int mani.? Do you need to remove the UPPER int man. only or remove both the upper and lower intake man to correct the problem. Any tips on the problem and the best solution, please let me know. Haynes can be vague and even leave big gaps in the step by step.