Notorious Oil Leaks

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alleycat

alleycat

10 Year 15 Year
Joined
Jun 3, 2007
Threads
29
Messages
115
Location
Charleston, South Carolina
Hello all - I have had two 80 Series and just bought a 2000 100 Series. There has obviously been and continues to be an oil leak (valve cover gasket maybe?) and I want to address these leaks and baseline the maintenance. On the 80 Series there were three famous oil leaks that plagued those engines. Are there any typical oil leaks with afflict the 4.7's in the 100 Series as well that I should start looking for?? Thanks and all help appreciated.
 
Hmm, I have 2 100's with a combined 435k miles, and not a drop of oil leaks on either. I'd say "notorious" for NOT leaking oil. Have seen reports of valve cover gaskets going, though I'd guess the vast majority are in the non-leaker category. After a 2F and a 1FZ-FE my driveway and wife appreciate the 4.7...
 
Agreed on notorious for NOT leaking. My 4Runner with the 4.7 did not leak a drop of oil for the 9 years I owned it and the LC100 I have right now is 10 yrs old with not even a weep out of the 4.7. Really amazing.

I see in the service history that my LC did have a PS rack replacement due to leaking, and PS pump as well but the engine and trans are bone dry.
 
I had a rear main replaced once. But I would tend to agree. Many 100s have no leaks. I have an 80 now. Way different story, as you know.


Sent from my iPhone
 
Turns out after reading a lot of post. Seems the screws just get loose and need to be tightened and the leak generally goes away. I changed my gasket and probably did not need to do it. I have already changed my rack other than that no leaks.
 
I've noticed something interesting just lately, on rear oil pan bolt. Not calling it a leak, but a slight seepage. On 01 with 165K, I just saw at the back of oil pan bolts, just one bolt with a drop of oil. On a 01 LX with 214, I see the same seepage just more evidence around same bolt.

This is the LX with 214K miles.
01 LX470 day 3 R&P Porpeller shafts & Spiders 013.webp
I plan On pulling bolt, cleaning and coating with a sealant, as done on the IS300 rear mains (known issue). Then re-torqueing all pan bolts. If returns after cleaning.
 
I'll add more leaks form lack of proper maintenance or neglect:

Power steering return hose tend to leak at reservoir. I believe this is caused be not flushing regularly & cleaning the reservoir screen. Pressure will build as this screen clogs, putting pressure beyond design limits on hose clamp. Once this develops; either move clamp forward 1/2" or re-clamp, new hose may be necessary if condition was aloud to go for long period.

One more area to watch for is seals is where front & rear propeller shafts enter transfer case and rear differential. This is cause by not servicing spider & slip joint at proper PM intervals, or damage to shaft(s). Either will cause unusual vibration in shafts. Same for front differential seal, from damaged (out of balance) front drive shafts.
 
I had a valve cover leak that was minuet and went ahead and replaced the cover. I currently have a seal that has a minor drip but im not losing major oil. I did replace the seal but issue is still there.

2001 w/ 196k
 
bucfl said:
I had a valve cover leak that was minuet and went ahead and replaced the cover. I currently have a seal that has a minor drip but im not losing major oil. I did replace the seal but issue is still there.

2001 w/ 196k
Click to expand...
Which seal?
 
Of my 2 100's one leaks pretty good from the steering rack and the other doesn't leak a drop. The one that doesn't leak was much better maintained and has had the rack replaced.
 
Engine oil leaks, I can't think of any but valve covers and pans might seep eventually. If cam and crank seals are replaced with timing belt, should never leak (cam seals on VVTI might not get changed due to effort involved if I recall). Then just the standard rack and CV leaks.
 
2001LC said:
I've noticed something interesting just lately, on rear oil pan bolt. Not calling it a leak, but a slight seepage. On 01 with 165K, I just saw at the back of oil pan bolts, just one bolt with a drop of oil. On a 01 LX with 214, I see the same seepage just more evidence around same bolt.

This is the LX with 214K miles.
View attachment 1225019 I plan On pulling bolt, cleaning and coating with a sealant, as done on the IS300 rear mains (known issue). Then re-torqueing all pan bolts. If returns after cleaning.
Click to expand...

I've got that same exact bolt seeping. Did you ever check back on it?
 
2001LC said:
I'll add more leaks form lack of proper maintenance or neglect:

Power steering return hose tend to leak at reservoir. I believe this is caused be not flushing regularly & cleaning the reservoir screen. Pressure will build as this screen clogs, putting pressure beyond design limits on hose clamp. Once this develops; either move clamp forward 1/2" or re-clamp, new hose may be necessary if condition was aloud to go for long period.
Click to expand...

This is the first I heard of this screen! is it in the actual reservoir? Can it be cleaned with a simple R&R of the reservoir?
 
m3roar said:
I've got that same exact bolt seeping. Did you ever check back on it?
Click to expand...
I've not driven enough yet.

PabloCruise said:
This is the first I heard of this screen! is it in the actual reservoir? Can it be cleaned with a simple R&R of the reservoir?
Click to expand...
Yes the screen is in the reservoir. This particular power steering reservoir had never been cleaned or system flushed before, and so screen was really gummed up badly. Using a lighter, I heated the plastic handle of a tooth brush bending it to get different curves working for me to scrub the screen.
 
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