sbmellen

So, during my drive from Show Low, AZ and Phoenix, AZ today, I noticed my oil temperature in excess of 250°F, probably by 5 to 10°F during hard climbs through the Salt River Canyon (ambient air temp at approximately 103°F in the canyon).

And for the first time EVAR, from what I've noticed, I saw my coolant temperature indicator go ABOVE top dead center (while driving), maybe a little bit.

All coolant levels are fine, coolant is approximately 4 months old, oil is about a month and a half old, 15W-50 Mobil 1.

When I got back into the Phoenix Valley, (108°F+ ambient air temp) oil temp was always at about 250°F (not an abnormal temp for me under long-distance driving in the summer).

Anyone think a secondary oil cooler is warranted?

Car is a 1998.5 A4 2.8 liter V6 with Quattro. Mileage is 92,250 or thereabouts.

TristanP

Another oil cooler is never a bad idea, I suppose.

sbmellen

In these temps? Wouldn't a thinner oil offer <i>less</i> protection than a thicker weight, given the temperature stresses?

Also, are there standard oil cooler applications for the B5 A4 2.8 out there? Or is everything a custom job?

Audi Junkie

+250f is no big deal. Try a double jumbo Mann filter and a thinner oil with esters.

Audi Junkie

The thin oil won't get as hot, therefore remaining thicker, get it?

sbmellen

Everyone (including here on B5 A4 forum) has recommended the heaviest weight oil for my V6, given the extreme conditions here in AZ.

You say the opposite.

Does not ***-pute.

Silver Streakin'

normal

JA4T

I have used it in Cali on my A4 for 8+ years. It works well in high temps. I would never put that low weight crap in my car unless I was in some "colder than a well diggers ***" weather! Keep with what you have.
J

Audi Junkie

I'm speaking in gerneral terms because I am just an amatauer Triboligist. In a system (an I-C-E in this instance), there is an ideal lubricating viscosity and the "system" tends to seek that viscosity through heat dissipation/retention and other ways. Say an ideal visc is a low 30 wt, 10cSt, the system will tend to retain heat until the once-thick-at-startup oil thins till an ideal visc/temp equilbrium is reached. This is demonstrated by the fact the engine runs at basicly the same temp with different lubes, incremental differences are not registered. That is until the equlibrim is out of balance, beyond a threshold that the oil runs hotter to "keep" thin and when you add the variable of high ambient temps, it goes out-of-wack....because it has ALREADY been producing excessive heat through Visc Seeking and internal friction from pumping losses. (Law of Entropy, greater pumping energy=greater heat energy) Try a 70 weight like Kendall Nitro 70 and see if it runs cooler, it WILL NOT. Forget temps for a sec, what are you trying to accomplish? Just keep the temp needle low? No, low engine wear is the target. Compare wear metals in suspension in used motor oil, light oils perform better then thick ones probally due to the fact 90% of wear is from start-up and warm-up, the 1st 15 min of driving. So, if your Engineer friends like high wear, low MPG, power loss and high oil temps, difficlut cold starts and regular stater changes, go with the "Ultimate" oil: Mobil 1 15w-50...you know, the one they don't even sell in Europe.

BTW- Factory-Fill is 0w-30 in 1.8t, 15w-50 is inappropriate for turbos and not recommended in the manual. I call it "tractor oil".

Audi Junkie

Here's a good starting point.<ul><li><a href="http://www.castrol.com/castrol/genericarticle.do?categoryId=82916482&amp;contentI d=6005377">http://www.castrol.com/castrol/genericarticle.do?categoryId=82916482&amp;contentI d=6005377</a</li></ul>