REQUEST: Aftermarket oil gauge in Montana

[bchaffin72]

While I am an old hand at installing aftermarket mechanical gauges in classic cars, I am not sure on later model stuff. Is it possible to install an aftermarket oil pressure gauge in addition to(or instead of) the standard oil can dash light on a 2005 3.5L V6? Does anyone know what's involved?

[Frosty]

All late model cars have sensors that are wired through the ECM and wiring harness of the car. If you remove or replace it with one that is not compatible with the ECM you will throw a trouble code. If you can find an available port on the engine to install a new oil pressure sensor (while leaving the stock one in place to keep the computer happy), I would go old school and get one that works without the need for a computer hook up like the ones you've hooked up on classic muscle cars.

Of course it begs the question, why do you think you need to do that? Don't trust the factory gage?

The best thing to see if you mount another sensor is to get a shop manual for your Montana, either a factory, Chitons and Hayes. You could also probably Google it. You need to know where the oil pressure sensor mounts. If there are 2 possible locations, then you can use the opposite location from the one being used by the stock sensor. An example maybe, it maybe mounted in the cylinder head. I don't know enough about the 3.5L to tell you where it could mount.

Perhaps Chaos could weigh in on this one....

[[ChaosweaveR]]

It's very possible. The LX9 can handle one, I'm unsure of the wiring as I've never added gauges myself, but I know Grand Am guys have done it often, even G6 owners, since the 05-06 G6s have the same engine as you do.

It may be different since you have the Montana. Killerspeed had one, I'll message him on FB and tell him to lend a hand in here. Either way, you can install one, that much I know.

[bchaffin72]

Thanks guys. Why do it? I like having an actual oil pressure gauge, not just a light Personal preference. And the Montana inspires me to do some of these things again. The Caravan didn't, for whatever reason.

I do have a shop manual, but I only bought it yesterday, so I haven't had much time to peruse it yet. Messing up the ECU by changing things was exactly my concern. If I can find a spare port, some way to do it old school, that may very well be the easiest, most risk free way to go.

[killerspeed101]

if your going to install one, make sure its electrical, im not a fan of having oil in the cabin and the wires would be easier, i wouldnt even bother, because u would need to run a T line to have both sending units, or the pcm will freak out and put it in limp mode. plus you would have to get somewhere to put it

[bchaffin72]

Thanks. If I do decide to do so, it would be electrical. I was never a big fan of piping an oil line into the interior myself, even on the old ones. I may, in the end, very well decide not to, but it's a thought right now, so I figured some outside opinions certainly wouldn't hurt.

[Frosty]

Killer - do you know, off the top of your head, if the port for the oil pressure send is in the cylinder head or on the block? If its the cylinder head, then the opposite cylinder head should have a plug that can be removed and a new oil pressure sensor can be installed into (albeit tough to get at being a transverse mounted engine). If it is a block mounted sensor, then something else will have to come up with.

My Lemans has its oil pressure sensor unit next to the oil filter housing adapter. Not sure if the more modern engines kept this arrangement or not.

[bchaffin72]

I don't know about the Montana yet. I'm looking through the manual now. My old 73 Audi had two, one in the filter housing and one at the end of the head, so I was able to keep the wire at the block for the light and run a whole new line for the gauge off the head.

[bchaffin72]

Not sure if there are unused ports in the heads, the manual doesn't have that info. I may have to physically look under the hood in the morning. The manual DOES show that the stock sending unit is next to the oil filter on the block.