420A Oil Weight

[crazyboy81]

I'm sorry I have been searching everywhere but I can't get the answer I need. I am ready to change my oil after replacing my valve cover gasket, as well as miles driven. My motor has almost 160k miles on it but the guy I got it from rebuilt it after blowing the head about 5k miles before I bought it. He claims to have port and polished the head, rebuilt the block, new timing, etc. My climate gets close to 20-80F in winter and 75-95 in summer. What freaking oil weight should I be running? I've been using castrol syntec 10w40. And adding normal 10w40 from time to time due to the oil leak. Who's got the good answer?

 

[talon1616]

10w30

 

[ilco187]

with colder weather you want thinner oil. 5w30 or 10w30

 

[tazndrew04]

just go with a 5w 30 and youll be good than go with a 10w30 in the spring. since your not turboed you dont have to worry about the thicker oil

 

[Absit]

Why has no one said "fix your oil leak" yet?

 

[crazyboy81]

Why has no one said "fix your oil leak" yet?

Because it was my valve cover gasket leaking oil.

The guy who rebuilt it didn't put a spec of RTV anywhere.

 

[VelocitàPaola]

Because it was my valve cover gasket leaking oil.

The guy who rebuilt it didn't put a spec of RTV anywhere.

Don't go crazy with the RTV when you get around to fixing the leak. Just apply it where the caps meet the head. See here for a detailed guide:

2GNT.com - Valve_Cover_Gasket_Replacement

I use 10W30 Mobil Clean 5000 (it's a conventional oil, not synthetic) year round, but I live in Florida. Then again, I'd still probably use 10W30 year round if I lived in the north.

 

[BoostFrenzy]

A lot of you guys are wrong.

It doesn't matter if you live in Arizona or the North Pole, you should be using a zero weight with whatever your engine likes to run for the second weight. Such as a 0W-30 or a 0W-20. Everyone says a zero weight cold rating it too low but it actually makes your engine last longer from less wear when cold.

 

[VelocitàPaola]

Well... the idea of multi-grade oils is that a single type of oil can be used in a variety of temperatures (hence the "W", for the oil's "winter" viscosity). So you're right that it shouldn't matter where you live as long as you're using the appropriate oil.

And I'll agree that 5W-30 or 5W-20 is probably sufficient for many cars, but our cars' engines just weren't machined precisely enough to warrant the 0W-xx oils that many newer cars use. I'm not sure why you think a more viscous oil will cause greater engine wear -- if anything, the opposite is true. Of course, there are other drawbacks to using a heavier oil than what you need.

For what it's worth, Mitsubishi recommends 5W-30.

 

[TSi Kid]

For what it's worth, Mitsubishi recommends 5W-30.

Can't beat OEM

 

[BoostFrenzy]

What most people don't realize is that the numbers on the can doesn't mean it's actual viscosity. The numbers on the can mean "grade". An engine is designed to run with an oil viscosity of 10 at approximately an oil temperature of 212 degrees Fahrenheit. The thing is though, is that viscosity is dependent on temperature.

For example:
A straight 30 "grade" oil will be perfect at an operating oil temperature of 212* by having a viscosity of 10. But the downside to that is that when you walk outside to your car on a nice spring day (say 75*F) after it's been sitting all night, that straight grade 30 oil now has a viscosity of 100. So you would be running your motor during warm up with an oil viscosity that is 10 times what that engine wants to run at. This equals bad.

This is where multi-grade oils come in. You can run something along the lines of a 10w-30 grade oil (Which I know for a fact a lot of guys run). Then you get the same viscosity of 10 at 212*F but on that 75*F day, you have a start up viscosity of 75. But, this still equals bad.

So the reason I recommend the zero "winter" grade is because now at that same 75*F spring day, that oil is sitting at a viscosity of 40. While yes, this is still 4 times thicker to what an engine wants to run at, it is 60% less thick then a 10 grade oil at start. This causes the engine to turn over easier and causes less wear on the engine. Less power to the starter motor = less energy that the alternator has to fill = less stress on the accessory belts = less stress on the rotation assembly. The oil is able to heat up faster and properly lubricate the engine which reduced metal to metal contact.

Currently, I am running a 0w-40 grade oil in my 4g63 and my engine is as happy as a clam. I may even submit some of it for an oil analysis.

 

[VelocitàPaola]

Less power to the starter motor = less energy that the alternator has to fill = less stress on the accessory belts

This is about the only thing you wrote that marginally makes sense to me. I still don't buy that more viscous oils cause the engine to wear any faster.

The numbers on the container are SAE oil viscosity gradings -- a direct measure of its viscosity, or in the case of multi-grade oils, a measure of its viscosity at multiple temperatures.

Really, I don't mean to offend you, but "what the engine wants to run at" and "this equals bad" aren't sound arguments. I don't doubt that your engine is running fine on 0W-40 oil, but that doesn't mean it's ideal.

Nonetheless, we're getting pretty far off-topic. Everyone seems to have their own opinion on which type of oil is best anyway, so the best advice for the OP is simply "Mitsubishi recommends 5W-30."

 

[red_devil]

You live in florida, it really isnt that big of a decision. Fix your oil leak and run the oil your owners manual says to run, its that easy. These oil threads are becoming repetitive.

 

[crazyboy81]

Yeah I fixed the leak before I posted this thread. I did the job properly, so far no leaks. I went ahead and bought Mobil1 5w30 Synthetic, I was looking into 0w30 as it was "eco friendly better for gas mileage" but I don't like to test much until I know from others it's ok.

 

[LD25Delta9]

To add to the discussion, there are numerous cases of people switching from a 5w30 conventional to a 5w30 synthetic and a leak magically popping up. This has to do with the conditioners in the oils and the way they affect different seals. This is also loosely related to why you are supposed to use conventional or mineral oil for engine break in.

IMO, 10w30 Royal Purple XRP every 2000mi.

 

[crazyboy81]

To add to the discussion, there are numerous cases of people switching from a 5w30 conventional to a 5w30 synthetic and a leak magically popping up. This has to do with the conditioners in the oils and the way they affect different seals. This is also loosely related to why you are supposed to use conventional or mineral oil for engine break in.

IMO, 10w30 Royal Purple XRP every 2000mi.

I've been running synthetic since I had it. It had conventional oil for a few thousand miles after rebuild.

Also, why would you change that uber expensive oil every 2k miles??

 

[VelocitàPaola]

Like I said, oil type and oil change intervals seem to be a very personal choice.

3,000 mile myth - Wikipedia, the free encyclopedia

 

[crazyboy81]

Synthetic doesn't have a bunch of oil conditioners in it. It's synthetic and outperforming compared to conventional because the man made oil molecules are all the same size. That's why it flows and lubricates better than conventional. Conventional oil's molecules are of different sizes. And high mileage conventional oil most likely is full of additives.

I hate the word conventional.... typing it sucks .

 

[JusMX141]

My 420A has gotten Mobil 1 since I bought it in 2002. If I didn't use Mobil 1, my next choice would be 10W30 Rotella in the winter months and 15W40 Rotella in the summer. Diesel oils not only keep your engine cleaner but also have a higher ZDDP content....especially the older (non-CJ4) diesel oils.

 

[krackit]

my garage always uses 5w30. oem reccommended. seems safe to me. and im in canada, so that's extreme colds and extreme heats.

 

[LD25Delta9]

Why would you change that uber expensive oil every 2k miles??

I'm permanently imbedded into RP's schfincter.

No, seriously though, like Paul said, it's just preference. I will say, though, that every oil change I can still see through my oil and it's still purple. My valvetrain is spotless.

On another note, after looking at a thread floating around here and with as often as I change my oil, I'm looking into the Brad Penn product line. More specifically the 20w50. It's got a really high Zinc and Phosphorus content and is about 1/3 the cost.

 

[bling5tatus]

I've been using 20w50 for years and years. No cold start/warmup issues due to the thick weight and never damaged a bearing either. Everytime I've looked at my caps they look great.