No guarantees are made
on the results, and anything you do yourself is at your own
Oil, Filters, Flushes
By Jesda Gulati
recommend, for a clean engine, using Mobil 1 0w-40 or 5w-40
(also known as the Truck/SUV formula) all year around. I
experience harsh midwest winters and long humid summers, and
drive hard. Mobil 1 10w-30 was a bit too thin on my Q45 in the summer and sometimes caused a
clattering noise on startup if the car sat for a few days
without being driven.
Mobil 1 is also the most
accessible high-quality synthetic oil, available at any
Wal-Mart, making it extremely handy for getting an oil change
during a road trip. For $30-$35 at any Wal-Mart in the country, you can
have your oil changed, fluids checked, and carpets vacuumed
within minutes. Just be sure to provide Wal-Mart with your own
filter, since they only carry Fram (not recommended).
Wal-Mart's own brand of Supertech filters, made by Champion
Labs, will suffice.
Mobil is now offering Mobil 1 Extended Performance, supposedly
good for 15,000 miles. No matter what motor oil you use, we
recommend AGAINST EXTENDED OIL CHANGE INTERVALS. This
may be a marketing move by Mobil to compete with AMSOIL.
Regular oil changes (2900-5000 miles) are important for keeping
the filter new, the oil level sufficient, and contaminants and
condensation out. For regular motor oil, the Q45 owners manual
suggests a 3,750-mile oil and filter change interval.
Wal-Mart now offers its own brand of full synthetic motor oil
called "Supertech", which has performed admirably in my Q,
though I have no oil analysis data to prove its performance
compared to Mobil 1. Supertech is bottled for Wal-Mart by Quaker
proof of Supertech being bottled by Quaker State.
AMSOIL, Valvoline Synpower, and
Redline are also worthy alternatives to Mobil 1.
Napa Gold, Mobil 1, Bosch Premium, or Nissan oil filters are strongly recommended. Joe
at Infiniti of Scottsdale offers low prices on Mobil 1 and
Nissan filters. Buy a few and keep them handy. If you find
yourself in a tight place and have no access to anything but the
filter selection at Wal-Mart, the higher-end Fram (X2, Double
Guard) products will suffice. Wal-Mart's low-cost Supertech
filters are made by Champion Labs, and are considered
superior to Fram's basic filters.
There are horror stories about Fram's basic filters falling
apart and destroying engines -- avoid them, please.
Before switching to a
1. Run an oil with high levels of detergents, such as Valvoline Durablend,
Valvoline Maxlife, or Mobil 1 5w40 Truck/SUV, to clean out
sludge and deposits before switching. The
reason for this is, most full synthetic oils such as standard Mobil 1 contain
fewer detergents, as they are not as necessary with a cleaner
2. Most Nissan and Infiniti dealers offer a
or Envirolution motor flush for $80-$150, which runs a heated
chemical through your motor and effectively cleans oil
passages. The Gumout flush is NOT
RECOMMENDED and could damage your engine if it is
This is a controversial
subject, but synthetic oils tend to be cleaner, leaving less
sludge and fewer contaminants behind. Most importantly, they
handle extreme temperatures in ways conventional oil
cannot. Corvettes, for example, require Mobil 1 strictly because
it eliminates the need for an oil cooler. No, the operating
temperature is not lower. The synthetic oil is simply better at
handling high temperatures (resistance to foaming). In the winter, they have a lower
pour point, allowing better lubrication during a cold weather
start, which is when the most severe engine wear occurs. To a
smaller degree, they reduce friction and slightly improve fuel
economy, but don't expect your Q45 to magically achieve 30mpg.
What do you use?
The following motor oils and
filters have performed admirably in my 1992 Q45.
6.5 quarts Supertech 5w-30 or 10w-30 ($17) or
Mobil 1 5w-40 full synthetic motor oil ($28)
1 regular Supertech oil filter ($2) or
1 Nissan oil filter or ($10) or
1 Bosch Premium oil filter ($6.50) or
1 Mobil 1 oil filter ($12)
Napa oil filters also appear to be well made.
Changed every 2900-3700 miles.
Why timely oil changes are as important as mileage intervals.
I take numerous short trips and
have many starts throughout the day, along with wide open
throttle runs -- considered a very severe duty cycle.
A thinner/lighter synthetic oil
is suggested for winters where cold startups require easy flow
for proper lubrication. We suggest a synthetic 0w-40/30 or
BobIsTheOilGuy.com regarding oil weights and cold weather:
5w number is completely and totally not comparable to the other
number. the Xw number is derived from a cold cranking simulator
test; the other number is the kinematic viscosity at 212 degrees
F. ANY fluid for the most part thins as it gets hotter and
thickens when it gets cold. Motor oil gets hundreds of times
more viscous when it gets cold compared to when it's hot and at
operating temperature. So, 5w-30 means that the oil passes the
5w cold cranking test (meaning it cranks less than 7,000 Cp at
-30 degrees C) and it has an operating temperature viscosity in
the 30 weight range (9.3Cst to like 12.3 Cst? or something like
Run a synthetic in the winter.
Most Q45 owners prefer to have
someone else change their oil, due to the filter location and
removal process for the underbelly cover.
BE CERTAIN that when you leave the shop, your
underside plastic cover is in place (assuming you had one
when you went in).
Also BE CERTAIN that the oil filter is replaced from
the bottom, NOT from the top, as that could damage the mass
air flow sensor or MAF connector.
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