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Old 03-24-2004, 10:01 PM
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Low Oil Pressure on Buick 3.8L V-6

I have just rebuilt my buick 3.8L engine and it seems to be running pretty good now. I got the carb tuned after much trouble, but now I have a new problem. I searched and didn't find anything on this specific motor, and not sure if I can take advice on another motor since this one seems to be quite unique.

On cold startup, oil pressure is between 30 and 50 psi at idle. After driving for a little while (5-15 minutes) I noticed a low oil pressure at idle (around 12.5 psi). At about 1200-1500 RPM, all is good again. When this first happened, I thought the oil might be thin from the engine break-in, so I went ahead and changed the oil and filter. Same thing happened after the oil change.

The first time this happened, I immediately stopped and checked the oil level which turned out being fine. When I started it up after sitting for about 5 minutes, there was white smoke from the exhaust only on start-up. Should I switch oil, or do you think I have another problem? (using 10w30 now)

TravisT

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Old 03-24-2004, 10:18 PM
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Low oil pressure is common for a 231 v-6, actually 12-13 lbs hot idle is good. These motors are famous for the oil idiot light blinking at idle hot. The factory even has low pressure switches to keep the light off.
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Old 03-25-2004, 08:52 PM
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Thanks for the reply, Bob. This seems like it could be very bad, even if it is normal. Is there any way to fix this? I already have a high volume pump with the medium pressure spring installed.
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Old 03-25-2004, 09:08 PM
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It is really not a problem, as long as the engine has normal pressure at off idle speeds. The cure is to get a new front cover and modify the oil passages.
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Old 03-26-2004, 04:55 AM
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Is there anywhere that shows you how to do this?
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Old 03-26-2004, 04:57 AM
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Travis my question to you is did you take the oil pump, clean it out and pack it full of petroleum jelly? If not you could have an air pocket in the pump.
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Old 03-26-2004, 05:51 AM
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Kenne-Bell used to have the diagrams for the modification. Try one of the Buick sites. www.buickstreet.com or www.v8buick.com
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Old 03-27-2004, 11:20 PM
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Some good tips & pics here too:

http://www.buickperformance.com/page1.htm
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Old 03-31-2004, 10:12 AM
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I did not pack the gears with petroleum jelly, but I did prime the pump with an oil pump primer. I would imagine that it isn't quite the same thing, but I have also heard people say that isn't really necessary. The gears were cleaned out, and again the pressure is good on a cold startup, but after the water temp reaches 180 and stays for a few minutes, the idle pressure drops. I will check out the websites and see what I can find.

Also, does anyone have any recommendation on which t-stat I should use? I am running a 180 now, and it doesn't overheat, but it is not very hot here yet. Should I switch it out for a 160?

TravisT
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