Biscuit

You'll never have a reliable baseline for comparison if you keep switching brands everytime you change your oil. IOW, the oil analysis information is basically worthless.

JKlad

Quick update here. Have done a good few thousand miles here now since putting in the 15W40 including a long road trip so I checked the oil level & pulled the PCV line to check for excess oil contamination. Hasn't used a drop (according to the dipstick; wont know for sure until I drain the sump at the next change & measure how much comes out) and the PCV line is still bone dry instead of dripping with oil, so the thicker oil has stopped being sucked up into the intake.

So in summary, just the results I had anticipated when I made the change to 15W40. Motor still runs smooth & quiet with all the former ticks & rattles disappearing completely and is generally much happier running this viscocity given the hot climate I am in. It's a shame I didn't run a series of oil analysis tests when still on the thin stuff so I could know scientifically what differences in engine wear the 15W40 makes.

Ryan0260

That's great information. Keep us posted on how it does. I'm switching to thicker oil when my consumption test is up

MacBeJeepin

So are you suggesting we start switching to 15w40??

Would it hurt the engines in N America right now (since we are headed toward cold weather)?

JKlad

Nah, in the northern US states in winter you'd want to stick to an oil with a 0 or 5 winter rating like the 5w20 Chrysler specifies.

The reason I changed to a higher-viscocity oil is that I am in a hot coastal climate (summer temps of 100-110F, dead-of-winter temps rarely if ever approaching freezing) and the thin oil that Chrysler specifies was leading to higher oil vapourization and consumption through the PCV system and inadequate protection at higher operating temperatures. Other manufacturers here where I am specify 15W40 for motors of similar design to the Crysler 3.8L iron block pushrod V6, with 5W30 specified as the winter fill for alpine areas only.

In fact, every other vehicle I've ever owned (and those I haven't owned but happened to look at the owners manual) has specified different weights of oil for different operating temperatures (my Mercedes specifies no fewer than 5 different weights depending on ambient operating temperatures). Chrysler just seems to have a "one size fits all" attitude to it's specified oil fill for it's vehicles which is heavily weighted towards thinner (low viscocity) oils purely for mileage reasons (in the federally mandated 36hr engine bench test, motors running the thin 5W20 get slightly better mileage so Chrysler specifies this weight in order to help them achieve their CAFE consumption targets for the fleet).

FLRubi

Subscribing to thread. Live in North FL and interested if switching to different grade would improve engine performance.

Goofas7070

I changed my oil this morning since the "change oil" signal flashed yesterday @ 21,145 miles. I used 6 delicious quarts of regular Castrol 10w-30 instead of the normal 5w-20. My engine is finally quiet! No more engine clatter with acceleration going up hill. Why did I not do this before? I have been trying all different types of gas to see if it would help when all along it has been that water-like 5w-20 oil.

SKULL_FACE

I use to have a Nissan Xterra, everytime I changed the oil, the engine was much responsive. a month later not even 500 miles after the oil and filter change, the performance went down. I have not noticed this on our Wranglers' but it does exists on some vehicles. Later I learned from a Nissan Mechanic that the engine I had in the Xterra , was a high Compression engine that broke down the oil very quickly. The new oil would be jet black within a month. Did not keep it long enough to say if it had issues later on. Should have switched to a quality synthetic oil.

I myself am switching from 5w-20 to 5w-30 weight. Currently using Mobil 1 Advanced Synthetic oil and a Napa Gold Oil Filter made by WIX, since switching to a Synthetic oil 8 months ago, I have seen a major difference on how my engine sounds better , longer time before dry starts,etc.

I do have one question though,, What is the true meaning of the first number ex: 5w labeled on motor oil. I thought it was the weight of the oil's viscosity referred to when the engine is first started, then the last 2 digits meant "IE: 20 or 30" took over when the oil is warmed up form idiling and now is reaching the higher end of the oil's operating characteristics under varying conditions,, temperature, towing, long idle, large hills, etc. Is this correct in a non technical way? lol.

Thanks,
*** SKULL_FACE ***

ronjenx

That's the way I understand it.

5W-20:
It behaves like 5 weight when cold, and like 20 weight when hot.

SKULL_FACE

Thank you, much appreciated.