I installed the 2003 Cts engine in my catera, runs great but, low oil pressure at idle, i dont know why, i checked the sensor seems ok, pressure is great when cold.. i am using Mobile 1 full synthetic 10w30 and i added lucas to thicken it up and it helped a little , could it be the filter? i heard something about getting the wrong type filters for these cars or something would cause this, i am using a mobile 1 filter on it, thanks

Congrats on your successful installation! Way to go!

The low OP could be so many things. How many miles on the new engine? Was its OP checked prior?

First thing I would do is monitor the OP with a mechanical OP gauge. Objective would be to rule out any possible incompatibility with the Cat systems.

If a mechanical gauge, external to and separate from the Cat, says you have low OP . . . . . . well . . . . . . . it's not a good day; because it would have been easier to cure such a low OP problem before you installed the engine. Had you been aware, I mean.

But I would not be concerned until the pressure is checked mechanically, with a separate gauge. Prior to that, my guess is some sort of sensor incompatibility. After all, techincally, in a Catera it's a "foreign" engine.

Good luck!

The engine has 50k on it, runs perfect, only time the oil pressure is low as when its all warmed up and i come like to a light and the idle gets low and so does the oil pressure..

The engine has 50k on it, runs perfect, only time the oil pressure is low as when its all warmed up and i come like to a light and the idle gets low and so does the oil pressure..
Understood. And that's useful information.

I continue to think possibly a sensor incompatibility. Also be CERTAIN your idle speed is at spec for your NEW engine. This speed might be different than the stock Cat idle speed.

My gut feel (strictly seat-of-the-pants):

You are facing an annoyance, not a catastrophe.

But regardless, and considering all your work and effort to get this far, you will be smart to chase the situation down and get a handle on it.

Good luck!!:) (more)

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OK, just thinking out loud here . . . nothing for certain because I do not know this with certainty . . . . but just talking . . . .

The OP sensor is a transducer of some nature. There are many different types of transducers, and even transducers of the same type can be designed with different calibrations.

You can get a feel for the situation, in general (only), I mean, here:

http://www.vdc-corp.com/components/press/archives/96/pr96-34.html

and here:

http://www.sensotec.com/pressure_sensor_appnotes1.shtml

That's not Catera-specific stuff, it's just on background. But one thing I take away from the reading is the variety which exists.

So, still just talking, one thing I might try in your situation is to substitute a standard Catera OP sensor into your new engine. This on chance the 2003 CTS engine might use a sensor calibrated differently, or one which employs a different sensor technology.

Our Cat engines were made in Europe, in England. I honestly do not know where the CTS engines were/are made; of course the car itself is made in the USA. But I do know your 2003 CTS engine was made at a different TIME than when Cat engines were being manufactured. This is by definition.

Bottom line, for whatever reason, the CTS sensor might have been updated or changed as compared with its Catera counterpart.

Again, nothing for sure. Just trying to throw out some ideas.

On the OTHER side of the above proposition, there is this:

http://autorepair.about.com/cs/troubleshooting/l/bl_obd_5.htm

Note how carefully the computer is monitoring the OP sensor. Look at P0520 through P0523.

It could be said that if your new sensor is wrong, the computer would ALREADY have noticed!

So again, nothing for certain. Just kicking around some ideas. You are on the scene and you will have to decide how to proceed.