I have a 1999 GP/GT that has just recently started rattling on the top end.. (134K) Funny how it started just 4 days after I changed the oil, but anyway.. I went back with a Delco filter and Castrol 10w30 oil as always.. I did change filters to a wix (post rattle) and put a half a quart of the that Magic Mystery Oil in it and it quieted it down some (not nearly as bad sounding at cold start now) but rattle is still there.. From what I understand oil "pump" and Lifters rarely fail on these cars.. Any suggestions on how I can determine or find out what this is??
What I have done is what's said above, I pull the oil filler neck off and watch as the car is running from a cold start and I don't see any oil movement on the top end leading me back to my original thinking (low oil pressure or lifters bad, or blockage somewhere..). I can get to the oil pressure sending unit and take it out and hook a manual gauge to it and see what the true pressure is since the light won't come on until pressure is like 4 - 6 psi.. Now after I drive the car for about 10 minutes, all sound goes away and the power is back to normal... Points more to lifters...
I hope this thread makes sense and if you have any questions please let me know or suggestions I will try and respond back the outcome!!! If I have to tear into the motor I would like to do a top swap while I'm at it but if I don't have to then... (still will just later!!) )
