Where is my oil going?!

[Stylo07]

It makes a difference. This is the most likely path, and because it gets burned, it goes along with your other no-leaks observation.

But again, wouldn’t there be some smoke? I promise I’m not in denial about possible bad valve stem seals! If it needs them, it’ll get them.

 

[Stylo07]

On mine yes....but only upon start up and only after having sat overnight. A slight 'puff' of smoke then gone very quickly.

Oil will seep past the Valve Stem Seals overnight and IF enough.... will produce a small puff of smoke at start up. During driving however, no. No smoke, it was just burning off completely enough in the cylinders.

I was at 316K on my engine when I replaced the seals. An engine with lesser miles might not leak as much.....but assuredly they are leaking some if original.

All of mine were rock hard and only the clearance between them and valve stem was providing any attenuation of oil seepage.

At this point, I’m thinking it’s probably a combo of leaking and using oil. Perhaps it’s time to pull the engine…

 

[LongDuck]

Catalytic converters are remarkably effective at staying hot enough to burn up hydrocarbons and various combustion gases with their platinum cores. You may not be seeing any smoke at all, because the cats are working effectively to burn it all up, but this would certainly show in emissions testing- if you have that in your area.

I own a 1st Gen Mazda Rx7 that INJECTS engine oil into the intake path to lubricate the apex seals (*there's no other easy way...), and it drinks less oil than you mention on this 80. With my 80 OEM short block and head work just 2 years ago, including new valve stem seals, oil consumption dropped to nil. Same oil, same driving conditions, same driver.

I'd say do the valve stem seals and monitor oil use. You should be pleasantly surprised.

 

[Stylo07]

Catalytic converters are remarkably effective at staying hot enough to burn up hydrocarbons and various combustion gases with their platinum cores. You may not be seeing any smoke at all, because the cats are working effectively to burn it all up, but this would certainly show in emissions testing- if you have that in your area.

I own a 1st Gen Mazda Rx7 that INJECTS engine oil into the intake path to lubricate the apex seals (*there's no other easy way...), and it drinks less oil than you mention on this 80. With my 80 OEM short block and head work just 2 years ago, including new valve stem seals, oil consumption dropped to nil. Same oil, same driving conditions, same driver.

I'd say do the valve stem seals and monitor oil use. You should be pleasantly surprised.

Great point about the cats. I figured my oil usage was too much for the cats to disguise completely, but perhaps not. Thanks for the info.

 

[BILT4ME]

Catalytic converters are remarkably effective at staying hot enough to burn up hydrocarbons and various combustion gases with their platinum cores. You may not be seeing any smoke at all, because the cats are working effectively to burn it all up, but this would certainly show in emissions testing- if you have that in your area.

I own a 1st Gen Mazda Rx7 that INJECTS engine oil into the intake path to lubricate the apex seals (*there's no other easy way...), and it drinks less oil than you mention on this 80. With my 80 OEM short block and head work just 2 years ago, including new valve stem seals, oil consumption dropped to nil. Same oil, same driving conditions, same driver.

I'd say do the valve stem seals and monitor oil use. You should be pleasantly surprised.

^^^ What he said...

 

[manofthewoods]

At this point, I’m thinking it’s probably a combo of leaking and using oil. Perhaps it’s time to pull the engine…

I will say, every single seal is on its last legs, or more likely, dead. When I re-did mine, the oil level sensor seal had turned into hard plastic, I couldn't believe it. I had to chip it away to remove it.
Pulling the engine isn't difficult, and makes every tough job child's play.
That's what I'd do.

 

[Stylo07]

I will say, every single seal is on its last legs, or more likely, dead. When I re-did mine, the oil level sensor seal had turned into hard plastic, I couldn't believe it. I had to chip it away to remove it.
Pulling the engine isn't difficult, and makes every tough job child's play.
That's what I'd do.

Makes a lot of sense. It IS a 30-year-old engine.

How many of you have found that you have worn rings, too?

 

[manofthewoods]

speaking only of my case. Mine had 372k miles. Cylinders were still in spec. No damage to any rings, pistons, valves. didn't burn or use oil. Did leak a little; mostly rear main seal. But, every seal was on the way O U T!
Lucky for me the PO babied the vehicle with frequent oil changes, etc. But, as mentioned above 25 plus years, IS a long time to ask for rubber to continue to do its job under the conditions we throw at them.

 

[Malleus]

That I have not done, but I know it would be telling. If that were the case, wouldn’t there be blue smoke coming out the tailpipe?

Mine didn't, and the intakes were coated with oil.

 

[robnicko]

might be worth changing the oil to a higher grade as a test?
Not sure about ambient temps that you experience however ive always run mineral 20w60 in mine and even when the valve stem seals were hard as rocks the oil consumption was minimal at time of HG failure, less than 1lt per 10000 kms.
How do the spark plugs look?
I'll probably cop backlash but I think full synthetics are too light for these engines unless fully rebuilt and used from day 1

 

[Rusty Marlin]

How do you know yours is a leak (legitimately asking)? Perhaps that’s the case with mine… Thanks for the info!

1) No smoke on cold start, so no vave guide leakage (had that on my old Camry, so I definitely know what that blue cloud rolling across the yard in the morning looks like)
2) When driving another car behind it, there's no smoke out-put even when throttle is hammered down.
3) Visual leaks at valve cover gasket, rear of engine (could be rear main seal or arch seal of pan), There's a leak on the front of the engine (could be front main seal or oil pump cover gasket or both) The entire underside of the engine is oil wet, but it's wind blown and doesn't drip on the drive.

 

[HARDGEAR]

Hi friends,

I’ve thoroughly searched here and on the internet, and I remain perplexed with where my oil is going.

- 1994 FZJ80
- 194k miles
- Uses one quart of oil every ~800 miles
- HG replaced by Toyota as PM at approximately 125k miles. Valve guides not done at that time. Never been done.
- No smoke on cold start
- No smoke on warm start
- No smoke when taking off fully warmed up after idling for a while
- No smoke under full throttle acceleration, including transmission kick down and up shift
- No smoke under steady load
- Timing cover oil leak — 1-2 drops on the ground/week
- PCV valve, hose and grommet just changed; old valve was fine
- Throttle body is clean
- Use Amsoil 10w 40 synthetic and Toyota 90915-20004 filter
- Plugs look good
- Valve cover hasn’t been off since HG change; doesn’t leak, miraculously
- Original cats, still seem fine
- Runs great, always has during the 11.5 years I’ve owned it
- Whatever it needs, it gets

I’m sure I’m missing some information that’s helpful to form an opinion, so please let me know what I’m missing. I don’t want to replace rings or valve stem seals if they’re not the root cause. Thank you all for your thoughts, questions, suggestions.

Have the spark plug gaskets been replaced with Oem?

 

[mudgudgeon]

My friend and fellow 80 owner followed me for quite a while yesterday while I created all the scenarios I could think of that make an engine that’s burning oil smoke. He said he saw nothing. I’ll try it at night, too, the next time I get a chance. Thank you for the tip.

Let the car coast down a long hill, punch the throttle at the bottom.
If it puffs smoke when you punch it, most likely valve seals.

My money is on valve seals anyway. Given the age and heat/cold cycles, they'll be rock hard and doing nothing.

I was also using quite a bit of oil before changing valve seals

 

[mudgudgeon]

At this point, I’m thinking it’s probably a combo of leaking and using oil. Perhaps it’s time to pull the engine…

I would not pull the engine just due to the oil use you are seeing.

 

[Stylo07]

1) No smoke on cold start, so no vave guide leakage (had that on my old Camry, so I definitely know what that blue cloud rolling across the yard in the morning looks like)
2) When driving another car behind it, there's no smoke out-put even when throttle is hammered down.
3) Visual leaks at valve cover gasket, rear of engine (could be rear main seal or arch seal of pan), There's a leak on the front of the engine (could be front main seal or oil pump cover gasket or both) The entire underside of the engine is oil wet, but it's wind blown and doesn't drip on the drive.

That sounds pretty much exactly like my scenario. Mine is leaking more than I thought — the oil pan is wet.

I’m familiar with the Camry valve stem seal smoke, as well. My ‘95 with the 5S-FE 2.2L farted every morning.

 

[Stylo07]

Have the spark plug gaskets been replaced with Oem?

View attachment 3259431

Yes, but it’s been awhile, and they could probably stand to be replaced again. Thanks for the thought!

 

[Stylo07]

Let the car coast down a long hill, punch the throttle at the bottom.
If it puffs smoke when you punch it, most likely valve seals.

My money is on valve seals anyway. Given the age and heat/cold cycles, they'll be rock hard and doing nothing.

I was also using quite a bit of oil before changing valve seals

Good idea — I’ll try that. Thanks!

 

[Stylo07]

I would not pull the engine just due to the oil use you are seeing.

No? It seems like it would make replacing the common leak sources and valve stem seals easier. I know the valve stem seals can be replaced in-situ, but if other jobs need to be done… I’m curious to hear your perspective.

 

[mudgudgeon]

No? It seems like it would make replacing the common leak sources and valve stem seals easier. I know the valve stem seals can be replaced in-situ, but if other jobs need to be done… I’m curious to hear your perspective.

Are you set up to pull the engine?

Allow 2 days to disconnect and pull the engine. Allow the same to drop it back in.
If you've got solid help, or done lots of engine in/out you can probably do it quicker. For the shade tree guy, there's a lot to disconnect, clean, organise, fix and replace/reinstall.

I'd do a thorough degrease, assess what leaks you actually have to deal with.
A lot of the common leaks are repairable in the vehicle.
If you want to do FR & RR crank seals, than you have no choice.

Pulling the engine out to fix a distributor o-ring leak fits with MUD level CDO* though






*OCD with the letters in alphabetical order as they SHOULD BE!

 

[flintknapper]

Pulling the engine out to fix a distributor o-ring leak fits with MUD level CDO* though

Naw, just double O-Ring it like I did mine, then no need to pull the engine.

No more leaks to deal with.