Bought a 71' Dart Custom about a month ago. Runs pretty nice. So I took it on a 240 mile round trip last week. Before I left I checked the oil. It was a quart low. I filled it with oil. Made the run up I-5 to Portland and back. At the frst traffic light in town the oil light came on. Two and a half qurts low. There are no leaks, so it's a thirsty burnin' beast. Anyway. light went off until today. Took a little moe than halh a quart this time. But the light still glows at idle or low speed driving. What gives? Poor oil pressure?

Matty

It could be one of four things. Low idle speed, bad sending unit, worn oil pump, or worn bearings. If I remember right, the light comes on around 5-7psi. One of the best things you can do is get a mechanical oil pressure guage, even if it is a cheap-o one. That way you can always moniter your oil pressure. You can also keep your oil light (which is good) if you use a T fitting at the pump. You will also know for sure if your pump is bad. For reference, I have 20psi at idle hot, and 45-50psi at crusing speeds. If its the bearings causing low pressure, it means it time to replace them as the clearences have gotten to loose to keep good oil pressure.
Two and a half quarts is alot of oil for a 240 mile drive! You sure your rear main seal isn't shot, blowing oil out the bottem of the engine and on the under side of your car? Is there any blue smoke comming out of your exhaust pipe? How about your breather cap, is it blowing oil into the air cleaner housing? The former two indicate bad rings. Had that problem with the original engine in my Satellite.

I think he means latter two. The gauge idea is a very good one, and I would add a wet/dry compression test to that to see where your rings (and I guess valves) are. However I doubt valve guides are your problem as there isnt nearly enough oil going through your top end to consume that amount of oil in such a short trip. In any case, if you don't have a serious external leak you are looking at a rebuild most likely. Don't forget to scrupulously examine your intake system to make sure that no dust is bypassing your air filter through a cracked cleaner housing, torn filter or missing air horn gasket. Maybe the previous owner ran it without a filter at all. And yes dust will do that kind of damage to an engine in a hurry.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Probably a bad oil pump.

Mitch

Thanks everbody! Some real good advice and food for thought. Anyway the light quit glowing soon after my original post. My guess is that it just took a bit of running for the oil th travel through. I will however continue to investigate the high consumtion. Regardless, it really is a fine running slant. Never had one before, glad I do now!

Matty

That wouldnt be it; it is possible that the relief valve was stuck open but there would have to be a lot of varnish and sludge present to hold the valve open with such a strong spring. Maybe your switch is grounding. But I would be concerned with the consumption, thats a lot. Check for puddles under the car and blue exhaust smoke and tell us what you find

_________________
I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.