Hey all ,
I have a 2000 3.4 6 cylinder with 4WD . Having an oil leak and think it's either oil pan or the oil cooler that I have seen some videos on.
I just turned 400,000 miles so I am sure that the oil cooler needs a new O ring and bolt seal. Will get those and plan on replacing just as maintenance anyway.
Since mine is 4 WD I am wondering if someone can link me to a thread that has the procedure for replacing the oil pan gasket since my thread search is unfruitful.
I guess I have to remove the front diff to do it ? Im hoping it's the oil cooler that's causing the leak but it is 25 ish years old now and 400K miles. So it's probably time.

Thanks for the help y'all ,
Craig

 

I don’t have a 3.4 in my truck(I wish) but this video seems to show some things?? Idk you tube has quite a few vids. He’s replacing his oil pump but also goes over where they could be leaking. Hope it helps a little. But from what I’ve seen he does remove the diff

 

Thank you Discombobulated. I watched it. Its involved for sure.

 

Get under there with a couple of cans of brake cleaner and get it fairly clean and dry, then drive it around some and look again. Over time the oil and grunge gets everywhere, but with it nice and clean and a little driving, it should be more obvious.

I resealed the oil pan on mine a couple of years ago, along with the oil cooler seals and hoses. And replaced the front diff with a regeared/lockered unit. And replaced the steering rack and hoses. A lot of stuff had sort of piled up and there was a lot of 'synergy' in getting it all done at once since it's all packed into that area of the car.

Pulling the front diff out is a PITA, more work than you'd expect. You have to pull the front suspension half apart on both sides. And it's heavy and awkward, and clearance in getting it out is very tight, ESPECIALLY if the motor mounts are sagged a little,. Which they will be unless you've replaced them in the last 10 years. It would be a lot easier if the front diff mount was a bolt instead of a stud sticking down through the crossmember.

With the diff out of the way access is pretty good to all the oil pan bolts, and plenty of room to get the pan down and out without needing to finagle the oil pickup first.

 

I pulled the motor leaving the trans, but that was because I did an engine swap with a spare 4runner I had, also did the rear main seal as 2 of the pan bolts bolt to the rear main seal holder at the back. it wasn't terrible to be honest and I had to pull 2 motors and reinstall 1, mind you I did unbolt the AC at the time since I didn't have gauges or a way to vacuum the system down and that way I kept its charge.

 

Thanks Jomoka . I'm going to do just that with a few cans of brake cleaner tomorrow. Then of course will have a better idea.
Thanks man.

 

Well it doesn’t sound fun either way, I have to do valve covers on my Subaru and I’m not looking forward to it, can’t stand oil leaks, it’s ok to let it go for a few but eventually it cakes EVERYTHING and then trying to figure out what’s leaking is a bear. Good luck!!!

 

Update : after washing everything down and some brake cleaner washing , I definitely need to do the valve cover gaskets. I am not sure this is exactly why I'm getting the oil leak , but it needs to be done. Ive ordered and received everything and will be getting it done as soon as I can. Ivd also already picked up the oil cooler o ring and bolt seal. Ill do that also while I'm wrenching.
I also need to do the timing belt, water pump, front crankshaft seal also so will be getting to that also. I will work my way down and see where the leak is coming from but it doesn't look like oil cooler or oil pan . While I'm doing the timing belt I'll look close at the oil pump also, and if that needs done then I will schedule it next. Even at today's prices I found the Aisin oil pump on Rock Auto for just over $80.
And for the record, I have purchased AIRCABINMAN's kit off of eBay for the last couple timing belt kits I've used. His kit is now approaching $400 for all the parts except for a couple other things I usually get to go with it. I'm NOT knocking his service at ALL and he does a great job. However, if money is tight, I may recommend getting all 15 parts off of Rock Auto. You can get everything there ( Aisin, Koyo, SMB ) stuff for around $230 with top of the line belts etc.
I know there are some other people on eBay selling kits for $160 or so, but with all the counterfeit knockoffs going on, I will trust Rock Auto instead and get the same quality as OEM . And In some cases , it will be OEM.
Will keep you all posted ! Thanks !
Craig

 

I've gotten 5 or 6 kits (mostly 4Runner 5VZ, a couple of HIghlander 3MZ's mixed in) from Aircabinman, they've all been genuine parts.

One time I did try buying a somewhat cheaper kit that said it had 'all OEM parts'. Lol, it came and all the parts were trash level knockoffs in plain white boxes that 'OEM' printed on them. As in the fake brand was 'OEM'. Lol, joke's on me. I was able to return it at least. No way I would bolt that junk on an engine.

 

I will order from Rock Auto. Can get quality there for just a little bit more.
And I agree with the Air Cabin Man stuff is legit and he is too !

 

Hey everyone,
A quick update.
I replaced the valve cover gaskets ,all associated gaskets around that also, some vacuum tubing , then did the timing belt, water pump and all (15 roughly) components around all of that including the belts.Interestingly enough, the main crankshaft seal seemed to have shrunk and so did the cam seals. When I used the puller on them, they came out SO EASILY ,it was almost scary.
So, most of the leakage is now gone ! I still have one small one and I think it may be rear main seal but gonna leave that alone for a bit. ( I did have a friends shop replace that about 6 years ago at about $500 )
I am having some misfires on cylinder 3 and 6 and rough running at about 45 -50 mph and 1600 RPM's . This was happening before I also replaced , plugs and wires and thought It would clear up but it hasn't . I ordered a second set of plugs and wires to try again and still same problem. I also had swapped two of the coils to see if problem would move to two other cylinders, but it did NOT. Ordered an aftermarket coil also and tried that , but same problem.
Sounds odd, but I'm going to try the fuel filter because I've NEVER replaced it ,and maybe I get lucky and it solves some things.After that, I will have to start digging and see what else I can find. I may start another thread at some point, also which is probably better than hijacking my own thread here!
Thanks ,
Craig

 

First I would say use OEM plugs, either NGK or the OE denso dual ground, and I prefer the OE Sumitimo wires, much better fit than NGK and they have a date of MFG, I just swapped my 1999 wires for 2025... runs the same. I would also suggest use OEM seals belts & bearings when working on these old yotas, and the rear main seal is usually done at the same time the pan gets pulled as the seal housing is bolted to the block and oil pan, you can pull the seal with a screw but if you try to pry it out it is easy to scratch the crank surface, and again OEM seal here as you do not want to revisit it, I'd pull the motor if I have to do this seal again rather than the trans as you usually want to pull the oil pan at the same time. The 1999-2002 injectors like to fail on these, if the misfire stays on a cylinder after swapping plugs & coils its usually an injector, a rusty fuel filter will help an injector fail sooner by adding particulate after the filter media when driven on bumpy roads, as will water in your gas and a hole in the top of your tank, be prepared to cut the front fuel line and replace it as it will not come off, still available OEM, and then you can remove the rear fuel line usually and save dropping the tank,.. which will be the next issue on a rusty 4R, and they are not cheap to replace after all the other components are purchased, did that last year and my truck has almost zero rust, but after hammering the bolts off it holes began to show up.. focus on the fuel filter first then injector and enjoy the ride, I used OEM injectors and did 3 at a time per rail and ordered the 2 aluminum crush washers for the banjo bolt joining the rails, if its the P-side you only need to remove the upper intake leaving the throttle body attached, easy peezy.

 

Thank you for all that , Malcom99. Its appreciated.

 

another quick question Malcom99 ,
You say that the front connection and fuel line will not come off of the fuel filter and to order one from dealer. I'm cool with that.
Do you think if I hit it, daily, with PB Blaster or the like, that it will penetrate enough to maybe come loose? I'm hoping that may work instead of replacing the fuel line but will probably have on hand, just in case.
This thing is still my daily driver .

 

Exactly, try wire wheel it really well using brass and soak it for the next week before trying, the line seizes to the fitting and the fitting seizes to the filter compression fitting, lube didn’t help in my sitch, (very clean truck too with not rust at all) the outlet of the fuel filter faces forward and corrodes in place getting pelted with sand and salt, I used flare wrenches with vise grips clamping the wrench to stop it from spreading and slipping and couldn’t get it off, even when the line was cut off using sockets wouldn’t work, in a vise afterwards is was almost impossible to break free and destroyed the fitting. Try it and if that fails cut it at the front and hope you can get the rear off so you don’t have to lower the tank, you can then spin the filter to help with leverage and save the rear line. The fuel line is one piece from filter to rubber fuel rail line, the plastic clips that hold the fuel line to the undercarriage are brittle so a heat gun helps to stop breaking them. You could cut it really close to the filter and stretch and flare the line once you get the fitting off and save a few bucks, the line is long enough to pull bends out to make up the length.

 

Ok great. thank you again for all the info . Great stuff
I'll let you know what happens, when I get to it.