shredder

To start off, i have a 96 A4 2.8 12V auto. I have already searched the threads and it seems like the most common oil used is the M1 5-40. i live in texas where the temperature is always around 90-110 degrees. the M1 10-30 isn't working right for my motor, the oil temp runs around 250 while driving around normally. i tried castrol gtx 20-50 and the oil temp was running much lower, about 225. so my question, what would be a fully sythetic to run with the extremely hot temps around this part?

moribundman

1. Is the oil temperature gauge working accurately? If you are concerned, double-check oil temps with an external temp gauge. If you can confirm high oil temperatures, check your coolant system.

2. 250 F seems high unless you are driving the car very hard or towing a boat up the mountain. ;-) I drive in over 100 F summer heat and oil temperature does not exceed 220 F when driving at highway speeds or even at idle.

3. The thicker the oil the more resistance to flow it will put up (inreased oil pressure). Increased flow means improved heat shedding. That means oil temperatures are generally LOWER with a thinner oil than a thicker oil.

4. 5W-40, 10W-40, 15W-40, 5W-50 or 15W-50 should work just fine in your application. You may want to try <a href="http://www.redlineoil.com/products_motoroil.asp?pvID=53&prodID=45&subcatID=1 4">Red Line 10W-40</a> or 15W-50. I would not use their 20W-50 in a street-driven engine, because it's total overkill.

5. I can't speak for the M1 10W-30, which does not meet the High Temperature/High Shear requirements of the 12v engine. Many folks run this oil successfully, but maybe not at your ambient temps.

shredder

Thank you very much! I'll try checking the actual oil temp with an accurate guage. The temp readings I quoted are when I'm just highway cruising with the AC on, so I figured it should be lower.