Oil pressure question

runawayabc123 · Feb 27, 2008

Well, this is a '91 3.8L V6 (Thunderbird), stock and NOT super charged.

This morning going to work, the oil pressure light was flickering on and off after the car warmed up. (Long nervous ride after I was already half way there.)

This afternoon, no light at all (other than on startup of course).

Some history: I changed the sending unit last Falling trying to chase down an oil leak (which was power steering). About the same time I ran a coat hang in the pan looking for sludge and found nothing and ran a quart of trans fluid with the oil to clean things up.

What do you think this is?

I have a few options: bad oil filter, bad sending unit, bad oil pump, gunk in the oil pan/screen in the oil pan, bad connection to the dash.

Also, does anyone know what the oil pressure is suppose to be?

Thanks for any help.

BarnStang · Feb 27, 2008

It could be low on oil causing the light to flicker? Or faulty sender and or faulty sender wire connetion. Not sure what preasure a 91 T-bird would have.
ALso, just want to make sure you know you posted in the Classic Tech forum?

runawayabc123 · Feb 27, 2008

Yeah, I was thinking about posting in the Fox fourm, but I spend my time here and trust you guys more. Oil isn't low. That was the first thing I checked. I also drove a couple more times tonight and no light.

On a more topic related question, the oil pressure gague (not light) on a 65GT/66 289, what pressures does its range roughly translate too? (And I guess, what should it be?)

Tim65GT · Feb 28, 2008

Just get a 0-80 or 0-100 PSI mechanical gage for $15-20. Hook it up temporarily in order to compare the actual pressure, as to the conditions when the light comes on.

Around 10 PSI at idle when engine is warmed up should be good with 10 PSI increase for each 1000 RPM.
10 PSI at 1000
20 PSI at 2000
30 PSI at 3000
ect...

Most oil pressure switches close and turn on the light around 5 PSI

Maybe put your old switch back in and see what happens.

You can use it on your Stang too.

Rusty67 · Feb 28, 2008

AllData has the oil pressure spec at 2500 RPM 40-60 PSI.

Maybe this attachment will help you:

runawayabc123 · Feb 28, 2008

Perfect! Thanks. I will give this a try on Saturday and report back. Still no light. I am also going to change the oil just in case it is something floating around in the pan.

runawayabc123 · Mar 1, 2008

Ok, I went to test the oil pressure and I was unable to hook up the pressure checker due to the power steering pump being in the way. I can get a socket down there, but not a wrench. My dad suggested something like this (a distributer wrench?) http://www.sears.com/shc/s/p_10153_...hanics+Tools&sName=Automotive+Specialty+Tools but it has an opening on one of the sides to slide past a stud or a hose (going to stay the oil pressure gage). It is closer to a crows foot wrench with a handle, but 6 points with one side missing. (What tool is this?)

Does anyone know where I could buy something like this on a Sunday?

Autozone has this: http://www.autozone.com/selectedZip...ail/initialR,NONAPP824/shopping/selectZip.htm and I think I will get that unless some has a better suggestion.

Rusty67 · Mar 2, 2008

Just take the power steering pump off. The pump doesn't need to be on for the engine to run.

runawayabc123 · Mar 2, 2008

Well, I tried the distributer wrench from autozone, that didn't work, it had too long of a swing and hit the powersteering bracket.

So, I got the crows feet from sears and that worked. (But it causes a little rounding on the fittings.)

I did the above oil pressure test, and the dash light passed.

The oil pressure gauge said the oil pressure was good to a little high.

So, I put in a new sending unit (the second one from auto zone and the last if it doesn't work either). And everything seems ok for now.

Oil pressure question

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