20w50 seems really thick for these engines. Unless you aren't getting good oil pressure with 10w40 then that stuff is probably not flowing well at startup and actually increasing wear inside the engine. If your oil pressure is that bad its probably time for a rebuild anyway. A good compromise is the 5w40 synthetics I mentioned before. You'll get good flow at startup, thicker oil for oil pressure, and its synthetic so you'll have longer oil change intervals. You'll make mother nature happier with those and probably find less wear on the engine and better gas mileage.

 

I think this link will help you out:

http://www.vtr.org/maintain/oil-overview.html

 

Are you using the same filter as you did before? A good filter and bad oil will turn brown just as fast as good oil and a bad filter.

I started using synthetic at 190,000 miles. My motor got quieter and at high RPMs it seems happier with it. I seem to have a bit of seepage at the valve cover gasket. Not a leak, just a seep. Its an old motor with old gaskets. It should be allowed to seep a little if it wants. I'm not worried about it.

FWIW I put in Costal full synth 5w-30 from Auto Zone. $3.49 per quart. I use Purolator filters from Pep Boys. That combination is good for 5000 miles between changes and the oil is still somewhat gold in color, not black like dino oil and nasty ass Fram filters did for me at 2500 miles. I do add a quart at around 3000-3500 miles between changes. Like I said its a high mileage motor at 201000 now.

 

It gets really hot here 90-95F and I'm going to try 15-40 Mobil 1 with a TRD filter.

I tow a Jet Ski that is around 100 lbs toughn weigth and about 1200 lbs.

Is that OK???

 

If you never plan to drive in cold weather at initial startup then 15w40 might be ok. Seems like 5w40 or 10w40 will flow better at startup.

The first # is the viscosity when cold. In the case of 5w40 its 5 which is very thin. Should flow very well. A 15w oil or 20w oil is already quite thick and won't flow the same for the crucial first few seconds after startup.

The second # is the oil's weight once it is at its operating temp which is different than the engine normal operating temp. The oil will thicken as it heats up due to viscosity modifiers added to the oil. The thicker oil stays put against cylinder walls and on camshafts better thus protecting them.

To max out the life of your oil, and subsequently the engine, do NOT idle your car to warm it up. The oil will not flow well in the engine. Drive slowly and don't gun the engine. During these warmup minutes the oil viscosity is adjusting as the engine heats up and excess moisture is being burned off. Letting the engine idle excessively after startup is the biggest thing you can do to increase wear.

 

I didn't know that...

I'd always accepted the common practice of letting an engine warm up to operating temperature at idle. This is bad?

Ryd

 

Idling is not good for the engine. If we are talking extremely low temperatures then yes idling may be good but as a rule of thumb you shouldn't do it. You don't make enough oil pressure at idle to get oil to the top of the engine where your camshafts and valvetrain are. Drive slow for the first block or two. Idling the engine in the driveway also doesn't put the engine under load which is necesary to get oil circulating faster.

 

Does this "idle is bad" rule apply for warm engines as well or is it most important for start-up? Taxis idle all the time...

 

Once the engine and the oil are up to temperature than there is no further wear. What is increased is emissions and fuel waste. The ambulances and fire trucks at work are all diesel and we idle them for long periods of time. Ever notice that at truckstops or on the side of the roads the truckers have their engines running while they rest? Some engines take a long time to warm up and they waste more fuel for the first few minutes than if the vehicle was just left idling. The benefit of power for the microwave and TV is obvious as well as having A/C.

 

And idling helps the huge turbo's in the big rigs cool down properly. I guess its their version of a Turbo timer.

 

I started using Mobil 1 in my 4Runner when it had 90k on it, and I have no idea what the previous owned used. My mechanic told me as long as you have a tight engine; no leaks, and good compression, it's okay to start using synthetic.

 

I don't agree with this method of looking at the cleanliness of oil-- because the types of oil and bases that compose these oils are different. It's like comparing Miller to Sam Adams to Guiness-- which beer is cleaner? Miller because it looks lighter and cleaner? Just thought I would point this out-- not trying to be a jerk, but the logic is a little flawed.

Someone else stated that a certain synthetic is paraffin based. Correct me if I'm wrong, but if it's a synthetic, then how can it have a dino oil base? Doesn't make sense to me.

 

CHANGING TO SYNTHETIC IS FINE UNLESS YOU HAVE ANY SORT OF LEAK OR SEAL DAMAGE. HAVE YOUR VEHICLE CHECKED OUT FIRST BY A CERTIFIED MASTER TECH.

 

I'll chime in. I just changed from dino to synthetic at 202,000 miles. I now have 208,000 with not a single problem. I know its only 6,000 miles, but i've only had the truck for a month.

 

Doing burnouts with 202K miles? Good choice in changing to synthetic!

 

FWIW: i switched my 93 to mobil 1 10w30 at 108k-ish and now, at 119k, i'm dealing with a pretty good leak: from the rear main seal or cylinder end plugs.

i believe the potential for the leak was there already, though. and now the smaller particles of synth are just sneaking out. it looks cleaner inside the oil fill cap and the engine is sure quiet and smooth now.

also, my oil pressure drops significantly as the engine warms. i think mobil 1 10w30 is pretty thin for a 30. i will be doing a flush and switching back to dino. will see how that works.

 

At 220,000 now with no leaks... but on the third set of tires.

 

A great link on motor oils, oil filters & gear oils.

http://theoildrop.server101.com/cgi/ultimatebb.cgi

 

I was going to make the same suggestion. Info on all of the questions in this thread come up daily on that board...

 

and i should have mentioned that the flush i'm going to do is with Auto-RX: which i'm using due to the crazy # of excellent reviews i've seen on the "BITOG" forum and thru independent web searches.

gotta switch back to dino oil to stop leaks, though, which i'm not crazy about. but, based on the opinions of people on the board with a helluvalot more oil skills than yours truly, i guess i'm tilting at windmills.

if i have a good experience, i'll be sure to post results here.