545svk

Hi, what oil (brand and rating) should be best for my car in 30 plus degree Celsius?

Thanks

LT Texan

I used Valvoline Racing conventional 20w-50 this last summer. Lots of zinc for flat tappets. No drama.

James Bailey

Doug Hillary of Airlie Beach did extensive long term testing with oil analysis and was very pleased with..."Mobil's Delvac 1 5w-40 Heavy Duty (HDEO) commercial diesel "mixed fleet" oil used in my ‘89 S4 over the last several years... "
The only real study with multiple analysis over the years. Basically proved that the recommended long term oil change intervals was just fine !! Good read if you look him up.

Fogey1

Here are some threads, Doug Hillary's at the bottom.


Budget Oils.
https://rennlist.com/forums/928-foru...et-oils-2.html

here is a posted pdf by andrew with alot of cool facts to help make decisions
https://rennlist.com/forums/6374650-post26.html

Mark, what's the name or number on the new Amsoil with the high zinc content?
This thread makes me wonder if the naysayers on the following broken cam thread have changed their minds.
https://rennlist.com/forums/928-foru...pidemic-2.html

My three rules of buying oil:
1. Pick a good name brand synthetic
2. Buy a viscosity that fits your driving and climate
3. Stay away from all oil with a CF-4 rating
CF-4 is the "new" environmentally friendly rating with low ZDDP numbers to protect catalytic converters.
Do a search for ZDDP in every forum, there are many threads on this.
Or read this:
http://www.cam-shield.com/acatalog/FAQ.html

Quote: Originally Posted by Mrmerlin
You really could use Dino for that matter, as long as it has the correct ingredients and its changed every 3000 miles

+1 There are some good dyno oils out there, like this:
http://www.le-inc.com/products.jsp?productID=258

take an oil sample and send it in*:
http://www.blackstone-labs.com/standard_analysis.html



More than you ever wanted to know about oil - Here are links to Doug Hillary's oil dissertations:

Oil Condition Report No 12
https://rennlist.com/forums/928-foru...t-no-12-a.html

Oil Condition Report No 11
https://rennlist.com/forums/928-foru...t-no-11-a.html

Oil Condition No 10 (Multi-page thread 1 2 3 4)
https://rennlist.com/forums/928-foru...t-no-10-a.html

Used oil analysis - thrust bearing wear
https://rennlist.com/forums/928-foru...ring-wear.html

Oil condition report No 9 - '89 S4 (Multi-page thread 1 2 3)
https://rennlist.com/forums/928-foru...o-9-89-s4.html

Engine oil used when racing
https://rennlist.com/forums/928-foru...en-racing.html

Oil Condition Report No 8 - Delvac 1 5w-40 (Multi-page thread 1 2)
https://rennlist.com/forums/928-foru...1-5w-40-a.html

Oil Condition Report No 7
https://rennlist.com/forums/928-foru...rt-no-7-a.html

Oil condition report No 6
https://rennlist.com/forums/928-foru...rt-no-6-a.html

PS Fluid
https://rennlist.com/forums/928-foru...-ps-fluid.html

Racing engine oils - "short list" (Multi-page thread 1 2 3)
https://rennlist.com/forums/928-foru...hort-list.html

Oil Condition Report No 5
https://rennlist.com/forums/928-foru...rt-no-5-a.html

Oil Condition Report No 4 (Multi-page thread 1 2)
https://rennlist.com/forums/928-foru...rt-no-4-a.html

Oil Condition Report No 3 (Multi-page thread 1 2)
https://rennlist.com/forums/928-foru...rt-no-3-a.html

Oil Condition Report No 2
https://rennlist.com/forums/928-foru...rt-no-2-a.html

Oil condition report
https://rennlist.com/forums/928-foru...on-report.html

ENGINE OIL SAMPLING - 928S4 - M2842-81K
https://rennlist.com/forums/928-foru...m2842-81k.html

bronto

I had low pressure issues in summer Fresno heat, and Royal Purple 20-50w helped a lot.

redpathtribe

Drive a lot of the year here in Phoenix, Arizona area in 40 plus degrees Celsius using Mobil 1 15-50. Daily driver with no oil issues.

82Porsche928

I use the Mobil 1 15-50 as well in Las Vegas. Also 40+ degrees in summer. Never a problem!

Alan

I used Mobil 1 15W50 for several years - my GTS didn't really like it, high oil consumption (very frothy), high oil temps, low oil pressure when hot in high ambeints. I have been using AMSoil 20W50 Zrod and it is really much better - maintains oil pressure when hot much better.

Alan

Chalkboss

I just started using Amsoil ZRod 20-50 too after a few stints with Mobil 15-50. Quite expensive but I want to try it out in the Central Valley heat. It does hold pressure better than Mobil when the engine gets "hot", although I have yet to try it out in summer temps >100F.

82Porsche928

When I do my oil change in late march maybe I'll give this a try.. What intervals do you change it in? I do mine late march and late September now...

JET951

The oil viscosity chart in you're owners manual printed by Porsche shows ( multi grade section )shows from minus 10 deg cel to unlimited high ambient temps = 15w-50 or 20w-50 oil viscosities

The reason for this is simple}
Once you get the oil operating temp in the Australian heat on a 5w-40 oil viscosity , meaning around 95 deg cel oil temp and above , all you will get is the oil pressure insufficient warning lights blazing away at idle because the oil pressure is just that ( too low ) , which in turn places the con-rod bearings ( 2 & 6 on a 928 & no 2 on a 944/944S2/951/968 at severe risk at high to max RPM ( even on the street)

But on a 20w-50 with decent levels of ZDDP ( AW ) which most if not all 20w-50 oils are allowed to have then lack of oil pressure hot is never an issue

But then again it says that in the owners manual by the people who built it

That's why we never have any issue with oil pressure or destroyed con-rod bearings , in the above Porsche models mentioned( and that includes a lot of track Porche club track events) , but after working on Porsche's since 1977 ( 37 Years )one would would expect "in the field" experience to show results in regards to what works ( 20w-50 ) & what doesn't= ( 5w-40 )

Now if we were talking about a completely different ambient temp range , say from minus 25 deg cel to a Max ambient temp range of + 10 deg cel , so in other words ( minus 20 to around 0 deg cel on average ) then in these conditions only I would use a 5w-40 engine oil with high ZDDP( say a racing 5w-40 to get the ZDDP ) , but not a primary diesel oil( Like Delvac) , because primary diesel oils foam too easily in a engine that revs or can rev out to more than double that of a big rig diesel engine

Its all very simple stuff

Victa

I use a cheap shell helix 20/50. My secret is to change it when it needs it. Even the most expensive oils don't last in high temperature situations. I stopped thinking of oil as a time or distance replacement thing, rather how it was lasting. I drive my car daily in traffic then on the open road. I recently replaced the cam cover gaskets. Everything looked nice and tidy, no sludge. That's my story. I hope it's the right one in the long run.

JET951

Simple , straightfoward & common sence Victa

ltbordo

multi grade oils come with the familiar "blank W blank format" The first number is sometimes known as the fluidity number and is the viscosity at cold temperatures. Think of this number telling you how well the oil "flows" when cold. The higher the number, the better it flows when cold. The second number is sometimes refereed to as the viscosity number and indicates how thick the oil stays when hot with the higher the number indicating it stays thicker when hot. A 20W-50 oil therefore will give wider temperature range protection that a 5w-30 oil. BTW, the W stands for winter.

john

WallyP

"The higher the number, the better it flows when cold."

The lower the number, the better it flows when cold. 5W is thinner than 20W...