1997 fzj80 120k mile engine oil recommendations? (1 Viewer)

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Hkfan7

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I wanted to see what everyone else is using and why?...no leaks, uses a quart between oil changes . Ive gone back and forth between full synthetic and the blend.
I've heard stories of full synthetic giving leak problems on occasion, I have not experienced any, even thought of just using regular oil blend at this point, also what viscosity is recommended with age and miles. thanks in advance guys.
 
When my 96 model FZJ80 had 120,000 miles, like the OP's, it barely used a quart every 4-5,000 miles (Mobil 1, 5W-30), but once it hit double that mileage the oil consumption began to shoot up rapidly (most likely due to worn valve stem seals). Heavier viscosity oils slowed that down somewhat.

IME synthetic oil doesn't leak anymore than conventional oils if everything is sealed properly, but with a 25+year old engine you should expect to start seeing some leaks.

Based on repeated engine oil analysis I've seen (on my 96 FZJ80) that the engine may do a bit better (less wear metals) with a slightly heavier weight than the US owners manual calls for ie: 10W-30, 10W-40, or 15W-40 depending on your local air temps, time of year, usage, etc.

One way to get real data is to send your used engine oil off for Engine Oil Analysis and base your choice of oil and oil viscosity on those results

 
Shell rotella 5/40 is what I have been using for years! With 335k I don’t burn much oil at all.
 
I have always used mobile 1, Delvac 1 in the 5w40 flavor in 1fz powered stuff. It’s what I have always had on hand for the duramax’s in family fleet, and a good 40w is speced for the 1fz in the rest of the world (other than ultra cold temps sub -20F iirc).

Never have had an issue
 
I'm a Rotella T6 5-40 user...mainly bc of the NC temp fluctuations and gives my oil pressure gauge a slightly higher reading.
 
When my 96 model FZJ80 had 120,000 miles, like the OP's, it barely used a quart every 4-5,000 miles (Mobil 1, 5W-30), but once it hit double that mileage the oil consumption began to shoot up rapidly (most likely due to worn valve stem seals). Heavier viscosity oils slowed that down somewhat.

IME synthetic oil doesn't leak anymore than conventional oils if everything is sealed properly, but with a 25+year old engine you should expect to start seeing some leaks.

Based on repeated engine oil analysis I've seen (on my 96 FZJ80) that the engine may do a bit better (less wear metals) with a slightly heavier weight than the US owners manual calls for ie: 10W-30, 10W-40, or 15W-40 depending on your local air temps, time of year, usage, etc.

One way to get real data is to send your used engine oil off for Engine Oil Analysis and base your choice of oil and oil viscosity on those results

Thanks Kernal,
It not being my daily driver, parked in the same spot all the time.. I have never seen a oil spot. I was really surprised when I checked the oil, after using it for work a few days. I've never known it to use that much oil between oil changes. I'm going to keep a better eye on the mileage and oil usage. For now, I think I'm going to replace the pcv valve I hear that sometimes can be the culprit.
 
Brand new 1000 mile motor, I use 0w-40 LiquiMoly or Mobile 1
 
Pennzoil high milage 5-30.
 
Nothing wrong with the Supertec stuff out of wally world. I run the standard dino version when i am going to be closer to home and then switch to the synthetic when i have a big raod trip planned. My pil analysis from blackstone have always been good.
 
  • Full synthetic 5W-30
  • Zero oil consumption on 19K mile young, all new OEM 1FZ-FE long block (happy happy, joy joy)
  • 5K intervals
  • If your engine is leaking stuff or burning oil, it's less the oil and mostly, if not all, due to the fact that it's a quarter century old aka "old pig" per above
 
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It’s that time of year for this thread again!

But really, being an oil nerd I still find it interesting. If it’s leaking, it’s leaking. Thicker oil might help a bit. Most people I talk to are running 40 weight oil in a 1FZ, because as noted in FAQ worldwide 40 weight is usually recommended. (US CAFE/EPA standards require thinner oils that are more resource conserving) your 1FZ can run a wide variety depending on operating temperature range.

My flavor is Mobil 1 High Mileage 10W-40, but used to run Delo 15W-40 for awhile.
 

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