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New Engine Using Synthetic Oil/Temp Guage Running High

I found a factory fresh 3.1 motor from a 1994 Cutlass Ciera and had my mechanic drop it into my 1995 Cutlass Supreme. We ran conventional 5W-30 oil for the first 2K miles, then AMSOIL 5W-30. I’m using a quart of oil every 2K miles. In my old motor, I never used more than a half a quart every 3-4K miles. I have 7K miles on the motor now. The oil isn’t on the ground, and I don’t smell any burning. I have noticed that my temp guage runs higher than before (close to the line before red) but never in the red. So, I guess I have two questions:

Why is the car using oil?

Why is the temperature guage running higher than normal|?

I don’t know what has changed, but I doubt it has anything to do with the different type of oil.

More info on my question: I just took a 650 mile trip and used a quart. I e-mailed AMSOIL. They recommended going back to conventional oil until the unusual consumption stops, then resuming use of synthetic oil.

You may want to pull the spark plugs and see if one or more is oily. It’s possible that the engine sat a long time without sufficient cylinder lubrication and scored a cylinder or broke a ring when it was cranked over for the first time.

As a follow-up to this conversation, I had the mechanic take the temp sensor off the old motor and put it on the new one. Now the temp gauge sits in the middle, right where it used to sit.

Depending on what you mean by “fresh”, it sounds like your rings haven’t seated properly or that if it was a rebuild, maybe the cyl walls were not properly cross hatched, etc. I would agree you don’t want to use synthetic until the rings have seated and the engine is broken in. have you checked your plugs to see if one or more cylinders may be burning oil?