I accidently bought 5w 20 synthetic oil instead of 10w 30 that I meant to buy. The first bottle on the shelf said 10w 30 but the rest were 5w 20. I was in a rush and never noticed that the oil was wrong until after putting it in and noticing it on the empty bottles. So what should I do now? Should I replace it right away or will I be fine for a while? I just don't feel like throwing away that much money away...synthetic isn't too cheap. The low oil pressure light is blinking but it was blinking before the oil change too (oil was very black and very thin - bought the car at an auction) My car is a 99 2.8 manual w/120k. What viscosity do you guys recommend I put in at this mileage?
I also have another issue...My tachometer is'nt working. It wasn't working...then it worked for once and at next startup wasn't working again. Now it never works...What would you guys do first? What steps to troubleshoot this problem?

 

your tach problem is the RPM speed sensor, not a big deal to replace...if you have a light BLINKING on your dash, you shouldn't be driving the car at all...if it's just lit up, you're ok...if it is blinking, you need to scan your car for codes and post them up here so we can help you...the 5w20 is pretty light, especially for a 2.8 with that many miles...i have 150 on my 2.8 and i run 20w50...i used to run the recommended 0w40, and i was burning a quart of oil every other month or so..since i switched to 20w50 (two oil changes ago), i don't burn any more oil...i'd run at least 10w40 in your car....it's really up to you whether to leave it in there or not...most people would leave it....but most people on this forum would probably change it out.

 

i am not an oil expert but 5w-20 should be ok but if you mixed it with a bottle of 10w-30 that would be a prob. sort of like mixing oil and water they realy dont mix and stay seperated leaving a gap of questionability

since you have a cell on for low oil pressure get that checked out. go to autozone or pepboys they will do it free. it might just be a sensor or your oil pump went.

the tach seems like a wire got fraied and finaly broke compleatly in half. i would take out the cluster and see if any wires are cut to start with.

 

I did scan the car for codes with a VAG-COM. There were no codes whatsoever about anything oil related. There is no check engine light. How exactly do I check the RPM Speed sensor? Whereis it located? Where can I get it? And I did mix the oil - put 5w-20 and one bottle of 10w-30. What do I do now?

 

I'd drain 2 quarts of the 5W-20 oil and leave the filter on. Get 2 quarts of the same brand of synthetic oil, 20W-50. Add it to the crankcase and you will be fine. Save the 5W-20 and do the same thing, next oil change.

I disagree with those who say "never mix different viscosities". I DO agree with those who say "never mix different brands (i.e.: Castrol & Quaker State). I mixed viscosities a dozen times on my '91 Passat...which had 237k miles and 175-180psi compression in every cylinder when I sold it.

--Larry

 

If there is that slight question in your mind, spend the money and change it again. Probably can't hurt to flush out that motor again.

Just my opinion.

 

As needed, add a higher viscosity synthetic oil, same brand, as needed.

 

drain some and fill w 10/40 . 2 quarts maybe.my car calls for 5/30 and i know it does not like thicker oils like 10/40 straight as it feels boggy when it is cold and stuggles a bit until warm.i dont understand how bentframe can run 20/50 and not feel it forcing its way cold through the engine

 

well i live in california so temperatures here are never too extreme...you can feel it for maybe the first minute of driving, then it's warm enough to run like any other oil

 

me too,i'm in socal and you are in norcal where it is colder