Oil Burn in FZJ80s - consensus? (1 Viewer)

[metaditch]

I found a ton of posts around here on oil burn, it'd be really helpful to get a fresh consensus.

Is oil burn something that you can deal with by topping off every so often, and leaving it at that? Let's say it's something like 0.5 quart / 1000 miles.

Does oil burn lead to other problems, or make the cause worsen faster, if left unrepaired?

Does it indicate that a head gasket failure is upcoming? If yes, does the rate of burn correspond with how soon?

Any other thoughts? Thanks in advance.

 

[ppc]

All depends on the reason for oil consumption. Typically on the 1FZ it's caused by worn valve guides/seals. Damage can be done to O2 sensors and catalytic converters. If it is from bad piston rings or scuffed pistons etc. then your potentially damaging the block and other internals and the failure could be catastrophic.

There is nothing a fresh consensus is going to change what has been posted in the past.

 

[Tools R Us]

... Let's say it's something like 0.5 quart / 1000 miles.
...

That is not something I would worry about.

 

[maxamillion2345]

15w40

 

[jpoole]

Your rate of burn isn't too bad but it could be a lot lower. If your valve stem seals are original and haven't been refreshed then they are a leading candidate for where your oil is going. Of course there are lots of ways for your oil level to drop from leaking to burning to getting pushed into your coolant, etc.

As a point of reference, I've yet to need to add oil to my 250k mile FZ between oil changes. Before I started driving my FZ I fixed the major leaks and did the HG/Valve stem seals. I've done oil changes at around 6k miles since doing all of the work and the level was stable/high during both runs. Oil is Shell Rotella 15w40.

In my opinion/experience the best thing about doing the HG as preventative maintenance is the chance to replace the valve stem seals and fix other leak sources, etc. while in there. It's nice knowing I'm not fouling the new spark plugs, O2 sensors, etc. with the excess oil consumption that my rig may have seen (I didn't drive it enough before working on it to know though).

 

[toastyjosh]

You did not tell us what oil weight you are running?? That being said because your in SD I would switch to 15w40 next change.

 

[Joe Link]

I’ve had right around the same rate of burn as you with 256k on the clock. I think I’ll try switching to heavier oil next change.

 

[bhsdriller]

I wish mine only consumed that much

 

[RFB]

i travel a lot 20K in 2019 alone in the 80 and she does not burn any oil whatsoever, I run mobil 1 and swap it out every 5K so that might be why I also get the large OEM filter from @beno until I ran out, now I run tandard oem filters 330K 120K on new head and supercharged. hope that helps.

 

[BILT4ME]

You can top off your oil due to consumption / leakage for many years, or until your emissions police deem it needs to be repaired (catalytic converters, not passing smog)

Excessive, long-term oil consumption will decrease the effectiveness of the catalytic converters and can affect the O2 sensors.

The first thing some here have told you is go to a heavier weight oil.

Interestingly enough, I made a mistake at my last oil change and poured in 10W-30 instead of my normal 5W-30 (as stated on my 710 cap). During this past oil change cycle, my truck decided to start using oil, and I had to pour in 1-1/2 quarts over the course of my oil change cycle, whereas I normally add ZERO. My oil change cycle is 7000 miles on a regular Quaker State dino oil.

Due to the higher viscosity, my engine decided it was going to leak more and burn a little oil due to the heavier weight oil. I have put on another 2000 miles on my latest oil change and my leaking and burning has stopped again, because I used the proper 5W-30.

Y'all can take it for what it's worth, but my HG was done by the PO at 146K (I bought it with 196K). They also rebuilt the head with all new seals at that time. I now have 282K on it and I have excellent oil pressure and I have not had to add oil to the engine during ANY time other than when I used the wrong weight of oil. I repaired the majority of all oil leaks (Dizzy O-Ring, VC, Spark plug tube seals, oil pump cover, front main) about 62K miles ago, so it stays fairly dry.

My Blackstone analysis on the oils that I do every other oil change have remained constant and ahead of any wear issues. Everything there is very good. Mine is a DD and I put on 15-18K per year.

 

[MoCoNative]

I probably need beat with a rubber hose, but my 80 is the wifes rig, so I end up adding a couple quarts whenever I get in it and the oil light is on. Damn thing burns oil like crazy. On a 5K mile interval I may add 4 quarts or more. It does alot of short hops, so I know that does not help, although its 6 miles into town, so when she does go to town it gets up to temp. It is leaking enough to keep it wet under the front crank seal/power steering pump area. Rear main also seems to be seeping along with wetness at the distributor. I replaced the leaking valve cover and plug seals awhile ago now. I suspect the valve seals may be the main culprit. Engine runs strong and does not smoke except a tad on a cold start in the morning I notice a little smoke as she leaves for the bus stop.

Truck has 175000 miles on it now, we bought it at 132K. It was evident it has burned oil for a long time, as the previous owner turned it over with most his junk in it, and three quarts of oil stashed next to the battery. He had written down the oil changes on the underside of the hood and noted the oil weight, he was using 10W-40 in the end.

A quart or two in 1000 miles was expected, the faster it is driven, like on a long highway trip seemed to eat up more. I was using Rotella T5 10-40 synthetic, as it came in gallon bottles for the diesel guys and is cheap.

I have a T100 with 261K miles, hardly uses any oil at all. I have owned it for over 10 years and got it at 118K miles. Under the valve covers and such it is very tarnished and was the day I bought it. I thought running Mobil 1 5W-30 in it would help clean it out, still dark stained when you look in the filler cap, never cleaned out. I have run this truck clear out to 10K on oil changes, when I drain it I will still have 3.5 to 4 quarts of oil left. I replaced the valve cover gaskets on it 2 years ago, aside from that seepage it has no oil leaks.

What I don't understand is the valve stem seals are the same part on the 1FZ and 5VZ engines from what I can tell. How can one do fine all this time and the other seems to be an issue for multiple people including myself. I thought I would change things up on the 80 this last oil change and sprung for the "High Mileage" Mobil 1 5w-30 and changed the oil on it week before last before heading out on a 1700 mile round trip to Arizona. Drove 85+ most the way when I could, normally it would have guzzled the oil, but consumption was uncharacteristically low. Maybe there is something to the Mobil 1, I know it has done very well in my pickup, guess I will try it for awhile longer in the 80. Also did pretty good on fuel consumption, got between 14.5 to 16 MPG, this is a stock rig, lower elevation really helped on power compared to NW Colorado.

 

[studawg]

Just adding this in here, dont go by the oil light. They are known to get dirty and send false signals. Mine will come on at idle sometimes and I know the level is perfect.