Questions and Answers
Century Engine Knock
Q. Dear Vincent, I read your suggestions about auto repair on line and found them very good and helpful. But now I'm have some problem about my car which I bought recently. I sent it in to a car repair shop, but they didn't found the problem. I wish I can get some useful advice from you. Thank you very much.
I used all my money and bought a 1996 Buick Century in February. Then two week ago I spent $1700.00 fixing the transmission. I was thinking that I was so unlucky that bought a car with a bad transmission then my engine starts knocking. The engine knocked before I had the transmission fixed, but that time the oil is about half quart low and I added some oil (5w-30) then the engine stopped knocking. But recently, the engine started knocking again, and the engine oil is still full. I went to the shop I repaired the transmission, they used a computer to read the error codes, it's:
P0133~Heated Oxygen Sensor Circuit Slow Response Bank 1 Sensor 1.
P0134~(I didn't found what this means)
P0135~Heated Oxygen Sensor Circuit - Bank 1 Sensor 1.
P0401~Insufficient EGR flow.I went to another repair shop and the guy told me the sound is lifter knocking. He checked the oil pressure and relevant stuff, but the engine just looks all right. He also changed the oxygen sensor. But since I've owed a lot of money already, I didn't let him change the EGR valve.
Do you have a wild guess about what the problem might be? Or which part should I check? I'm thinking that maybe the engine oil I used(5w-30) is different from what were in there (the dealer might have 10w-30 added in the engine), will this possibly cause the problem? And will higher octane rated gas or any gas treatment help? I really appreciate for your help.
Sincerely yours,
Yi ZhuangA. P0134 is: O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1). So you had a bad O2 sensor.
Wild guesses are easy to come by and I try to do a little better than that. Not being able to here the type of noise it is, I will have to go with the second mechanic. If it is indeed a lifter noise, then switching to a 10W-30 oil will help keep them from tapping. Changing the fuel or adding gas treatments will not help the noise.
Keep in mind however, that if the lifters are starting to go bad, this will be a temporary fix. But it should buy you time to recoup from the transmission repair before you have to worry about it.
Additional Information provided courtesy of ALLDATA
