Oil Light?? This is strange... April 07, 2007, 06:08:18 PM Drove home the '82 5.0 T Bird today from sellers house. Very odd stuff. The oil light came on, but the faster I drove down the road, it would flicker, and as I was up to about 75 mph, it was nearly out. Drop back down to 55 or so, and the light was on rather brightly. Keep in mind I drove it 35 miles home! Anyhow, I noticed that if I put it in drive, and not OD, the rpm would make the light go out. I also found that is I rapidly let off the gas completely, it would go out. In town, when I would pull up to a stop light, it would glow bright, but hammer it, and it would go out, and then back off real fast, it would go out?Having it survive the 35 mile trip and not lunching the motor tells me that the pump may be on the way out, or the sender it fubar.In park, the light will go on, but I give it half throttle and it will go out.So, the pump? Or sending unit?? Quote Selected
Oil Light?? This is strange... Reply #1 – April 07, 2007, 06:13:30 PM Did you check your oil level?If so,how is it? Quote Selected
Oil Light?? This is strange... Reply #2 – April 07, 2007, 06:14:00 PM Try the oil light switch (sending uint) first. It's cheaper & easier to replace. That or hook up an oil pressure gauge to find out what pressure you're really pushing. Quote Selected
Oil Light?? This is strange... Reply #3 – April 07, 2007, 06:14:17 PM Oil level was barely above the full line, Quote Selected
Oil Light?? This is strange... Reply #4 – April 08, 2007, 04:07:24 AM usually every so often i get a check oil light in my 5.0 and i usually give it half a quart (or less, maybe a 3rd) and mine goes out. i'd give it a nice full oil change and then see how it works out. Quote Selected
Oil Light?? This is strange... Reply #5 – April 08, 2007, 10:54:04 AM Another thing to check is to make sure the little connector is tight. If it is loose it could shake around and cause a light to flicker. Had it happen to me. Replaced it with a new one form the parts store. Quote Selected
Oil Light?? This is strange... Reply #6 – April 08, 2007, 10:56:44 PM Install a mechanical oil pressure gauge to be sure of proper oil pressure and then replace the sensor. I just had the same thing happen to my daughters S10. Oil pressure gauge was showing very low. Installed mechanical gauge and there was 30 psi difference between the factory gauge and my mechanical gauge. I replaced the sensor and gauge was accurate again.Bill Quote Selected
Oil Light?? This is strange... Reply #7 – April 09, 2007, 09:59:48 AM Quote from: MrBill88Tbird;138962Install a mechanical oil pressure gauge to be sure of proper oil pressure and then replace the sensor. I just had the same thing happen to my daughters S10. Oil pressure gauge was showing very low. Installed mechanical gauge and there was 30 psi difference between the factory gauge and my mechanical gauge. I replaced the sensor and gauge was accurate again.BillWhat Mr Bill said... Always verify pressure with a external gage...Now MR Bill... Sensors operate the computer systems, ABS etc... SENDERS operate gages... Quote Selected
Oil Light?? This is strange... Reply #8 – April 09, 2007, 11:24:10 AM Low RPM's=lower oil pressureHigher RPM's= higher oil pressureLow oil level=low oil pressureYou have a low oil level hence when your rpm's were low you have low oil pressure and walah your oil light come on. You kick it and you rpm's rise and so does the oil pressure and you light goes out. What does this all mean? PUT SOME STINKING OIL IN YOUR CAR!!! Quote Selected
Oil Light?? This is strange... Reply #9 – April 09, 2007, 02:39:01 PM Quote from: misteramx;138823Oil level was barely above the full line,Quote from: Slinky;139017Low RPM's=lower oil pressureHigher RPM's= higher oil pressureLow oil level=low oil pressureYou have a low oil level hence when your rpm's were low you have low oil pressure and walah your oil light come on. You kick it and you rpm's rise and so does the oil pressure and you light goes out. What does this all mean? PUT SOME STINKING OIL IN YOUR CAR!!!If the oil is above the full line how is it low? :confused: Quote Selected
Oil Light?? This is strange... Reply #10 – April 09, 2007, 09:04:50 PM Well, I did one better, I did do a complete oil change with new filter today. Although the problem isn't as prounounced as before, when I come to a stop now, the oil light will flicker then go solid. Pull away from the intersection and all is fine and now cruising appears to be fine at a steady rate. I can put it in park, and increase idle by about 300-500 rpm and the light will go out.Next step is the sending unit, but somehow, I'm not as convinced it's that. Hmmmm.....Speaking of...WHERE is the oil pressure sending unit on the block, I have an oil gauge and adapter that I'd like to throw in there before going any futher... Quote Selected
Oil Light?? This is strange... Reply #11 – April 10, 2007, 11:22:23 AM Low oil level does not equal low oil pressure. It’s not gravity pressure or something it’s going through a pump, if the oil was too low then the pump is sucking air then there is NO oil pressure not LOW oil pressure. If there is enough that the pump is not sucking air then there is enough. As pointed out by 88sportcoupe “oil is above the full line how is it low?” it’s not low. Oil pressure is created by the pump forcing the oil through the motor. A fresh motor will have High (60 lb) of pressure. As the bearings ware this pressure will drop, seen older cars with 30-40 psi? The space the oil is being pushed through is larger = less pressure to push it through. Oil weight will make a difference also. He did an oil change and it improved= the Oil in it was worn and thin = less pressure. Bring the R’s up and the pump is pumping faster throwing a larger quantity of thin oil into the large space, pressure increases, light goes out. Change the oil again and go to real heavy oil, I bet your problem will be even less pr0nounced. How many miles are on this bird? I’m guessing it’s about time for a rebuild, some new bearings at least. Heavy oil wont FIX it, just make it less obvious. Quote Selected
Oil Light?? This is strange... Reply #12 – April 10, 2007, 01:51:12 PM Jim,That's the real kicker....this car has a whopping 77K original miles. Really. It was literally a little old lady car, I got the car from her son who brought it back after she passed away. Granny owned since 1983. Vinyl roof is still MINT! But, those miles doesn't mean granny didn't abuse it, like never change the oil, ran it hot, ect, ect.I am suspecting bearings at this point. I don't think rings or valve guides because there is no smoke from the exhaust.I had thought about the thicker oil too, and I'll try that, any suggestions? 20/50 maybe? Wonder if there is any oil additives that will help. Either that or I can up the idle another 300 rpm and forget about it:)I'd like to be able to get it through the summer on the cheap, so I'm open to suggestions. Unless someon has a good running 302 laying around:) Quote Selected
Oil Light?? This is strange... Reply #13 – April 10, 2007, 02:17:54 PM Your right, it could have been abused so that could explain bearing ware. Rings and valves wouldn’t cause a low oil pressure situation. Worn/defective oil pump would. As for oil additive’s I have no experience with them. Have “heard” (ßRead Hearsay) horror stories (gumming everything up) but that’s about it. As for 20/50 if this is indeed the problem 20/50 should prove the theory out, but like I said not “solve” the problem. (make the light go out but won’t fix the bearings) And actually with the oil you have in it is most likely still oiling things, flowing, just not under pressure. As for a good running 302, yea I actually do have one, came out of that 1984 Mark I stripped. Unknown miles. But is also in Washington State so kind of out of reach. I pulled it because it ran so strong (would throw that LSC sidewise easy enough) I hated to s it. I want to go HO so I’m looking for another motor for my bird. You want to drive to Vancouver for it I’ll let ya have it for $100. Intake has been removed but is still here with that “other” type of FI on it (looks like a carb, what they call that Throttle Body FI?) I think if it was me I would just give it the 300r’s and start looking for another motor to start building. Quote Selected
Oil Light?? This is strange... Reply #14 – April 10, 2007, 02:44:10 PM QuoteSpeaking of...WHERE is the oil pressure sending unit on the block, I have an oil gauge and adapter that I'd like to throw in there before going any futher...If it's like the 1983-88 cars, the sending unit (technically a switch for cars with warning lights) is on the block right above the oil filter and to the left, if you're looking at the driver's side of the engine. It should be directly screwed into the block; you should see a small harness going to it. That's the bad boy. For cars with sending units for an oil gauge there was a 5" long extender pipe that screwed into the block, then the unit was screwed into the end of the extender. You may need to do that for the gauge you plan to install.Just FYI...I had this same problem with the original motor in my old '88 Blue Max V8. I tried heavier oil and the situation did slightly improve, but it never got better. Turned out the bearings were shot due to oil starvation. Apparently at some point before I bought the car, a stuttering/hesitation problem developed and some stump-jumper cracked into the block and tried to find the source. He/she didn't succeed but upon replacement of parts, they didn't tighten everything down according to specs. Oil poured from every corner of the motor, very slowly, probably over several years. I don't think the previous owners checked the oil between oil changes (but they did have it changed every 3,000 miles). That's where the starvation occurred. Eventually it killed the bearings. ed motor couldn't generate good heat in the winter, but it sure got good fuel economy. Anyway...that could be the same situation you're in. But definitely check the oil pressure from your gauge, and if it's acceptable, change the sending unit (switch). It can't hurt. If the pressure is indeed low, you're looking at a failing oil pump, or the need for a rebuild, or both. I hate to see sub-100K motors needing a rebuild...but it does happen. Sounds like this one may not have had an easy life. Quote Selected
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