A4orce84

So was cruisin to my friends house in "my" 1990 Audi 100 for the summer, and it was in the upper 90's temp. wise and I had the A/C on full blast. I was doing a little highway driving, and then the last few miles were on some streets. As soon as I pulled away from the first light my oil pressure light blinked at me for 2-3 min, but I couldnt stop in the middle of the road, so I kept going because I was really close to my friends' house. It kept blinking and beeping at me and showing the light in the Auto-Check System display. Just the same logo as the engine oil temp and engine oil pressure gauges. I checked the owners manual and it says that the engine oil pressure light comes on when the engine oil pressure is low. Unfortunately by the time I figured all this out it was already pretty dark, and there was not enough light to read the dip stick. So i risked it the 15 miles back home. The whole drive back I was kind of cautious the first half but no light came on, so I was driving it semi-hard to see if I could reproduce the warning. But nothing, it didn't come back at all. I'm still going to check the dipstick and will most likely top off the oil tomorrow, but still any ideas? Fluke in the system? Just wanted to run it by you guys, and see what you might think. Thanks.

--Asif

XcellR8edAudi

oil pressure issues are not to be ignored or neglected. check to amke sure your oil is full, check to see if your oil pump could possibly be failing or dead, as well as check to make sure your oil/pressure sensors aren't leaking and are in good working shape, also consider installing an aftermaket oil psi gauge to keep an eye on it, even if the guage has to just be sitting on your dash, better than wrecking your motor. good luck, and let us know what you come up with.

A4orce84

AIM or MSN? I'd like to talk about this further with someone who is familiar with the problem. Thanks.

--Asif

CARSNPLANES

Extreme hot engine temps (what was your temp gage reading?) will thin the oil, sometimes so much so that it will make the oil pressure sensor think it has no or low pressure. The A/C can definately bring the eng temps up. Does your electric fan turn on to the proper speed when you select A/C? How about using a higher viscosity oil or better yet, install a direct reading oil pressure gage for checking.

rooster 2

Suggest using 20-50W motor oil in the summer

rajan_bhirud

Highly recommend oil pressure gauge. Let it sit on the dash. It comes in 0 to 100 PSI dial.
Also use Valvoline Maxlife 20W-50. I am using it in NJ and very happy with its results.
None of my ancestors are connected with Valvoline and I do not work for them.
By the way does anyone know what should be the oil pressure in numbers when engine is hot and idling and speeding at say 70 mph? Thanks.

A4orce84

I have Castrol 10W-30 right now, but I guess that is too light for the uppder 90's / Full A/C ?

A4orce84

Well Guys,

Was able to check the dipstick today, oil level is good. 3/4 of the entire hash were covered, and this is after a 10 min cruise, so I'm pretty sure everything is pretty constant. Some of you saying the oil pressure light could have come on because of a lightweight oil. I currently am using Castrol 10W-30 in my Audi 100, and I thought that would be enough for the summer? I guess not, some of you suggested goign with a heavier oil such as 20W-50....any one agree? Or any other suggestions, I'm most likely, now that I know that the oil level is in good shape (plenty of oil), will see if the light comes back, and if it does will top off with a heavier oil. Or should I do a complete oil change? I guess maybe its a little hotter than last year, but I don't ever remember having this problem ever before. But then again I'm not in my home state so I dunno...

--Asif

XcellR8edAudi

do a full change with 20w-50 and install an oil psi gauge.

A4orce84

my dad's Audi. And in about a month I'll be back at home, alot cooler temp wise. So I'll probably do the change, but I don't think the gauge is really necessary. This is probably the car's last trip out of it's homestate for such an extended period of time.

--Asif