5vz-fe Oil leak

Hello,
First, I want to say how awesome it is that there are so many people out there who are enthusiastic about these trucks and want to help others to maintain their legendary vehicles. I have spent so much time reading through these forums and they help sooo much. Thanks again guys.
I recently bought a 1998 Tacoma, 3.4L 4x4, automatic, with 360k miles on it for $4300.
First off, I got a CEL P0441 Insufficient purge flow. Did some reading, replaced the vacuum switching valve and bingo bango fixed it.
Next, the idle was a little rough so I cleaned the throttle body, cleaned the idle air control valve, and services the mass airflow sensor as well as replaced the air filter. The idle, is still a bit rough sometimes and, while sitting at a light, strikes fear of dying out. maybe she's old and tired. I digress.
recently, I started stabbing at an oil leak. I HATE when my vehicles leak oil. so, I cleaned the crap out of the engine, did an oil change and added UV dye to it to get to the bottom of it. I found a little oil coming off the back of the block and located the problem. Whoever did the Valve cover seals last, was not able to reinsert the valve covers into position without fudging up the seal and knocking a corner out of place before torqueing it back down. Pic attached. and this was causing an oil leak. so, I replaced the valve cover seals, resealed the half moons and replaced the rear cam plugs. bingo bango valve cover oil leak fixed!
I buttoned everything back up, cleaned the engine again, replaced my skid plate and was happy as pie for about a day... still leaking oil. everything messy and oily all over again. kill myself. I checked the back of the block where my new plugs where installed and also ran a paper towel over the newly sealed half moons and found that my replacement job was a success and there was no oil coming from the said areas. so, whats next? with oil dripping down the bottom of the bell housing and oil pan I thought well shucks, gotta be the rear main seal. so I geared up the drop the tranny and watched all three of timmy the toolmans transmission videos. then, I thought... but what if maybe it,s not the rear main seal. so I removed the access plate granting me a view of the flexplate (flywheel?). the flexplate (flywheel?) itself is dry. no oil on it, if it was the RMS wouldn't there be oil all over this thing (pictured)? instead, there is oil on the access plate itself and around the outside of the inside of the bell housing immediately surrounding the access plate. so, I really looked at where the oil seemed to be coming from and, from what I can tell, it seems to be the oil pan gasket. near the rear of the oil pan, oil seems to be leaking out and then proceeding to drip down into the access plate area and eventually down to the lowest part of the bell housing making it look like the rear main seal is going. when, in fact, the RMS may be fine and just the oil pan gasket needs to be replaced. JUST the oil pan gasket??? yeah right, pain in the ars job too it seems to be.
does anyone have any input on whether or not the flexplate (flywheel?) being dry indicates the integrity of the RMS?
so, here I am with 2 potential oil leaks in oil spot.
the oil pan gasket can be replaced by dropping the front diff. which, is a pain in the ars, as I understand. the RMS can be replaced by dropping the transmission which, is a pain in the ars, as I understand. both can be replaced by pulling the engine, which is a pain the ars, as I understand. so I am currently leaning toward pulling that engine. mind you it has 370k on it and my idle is intermittently rough. I has the valve covers off and, I know, I should have checked the clearances using a feeler gauge. but, I called the local Toyota dealership to check their stock on valve shims and they would have to be special ordered, which means, i'd remove valve covers, measure, turn, measure, turn, measure the clearances and check spec. then, of the valves that were out of spec, remove the shims, mic em, put them back in, turn, remove other out of spec valve shims, mic em, do the math, order from dealer, wait a week then replace all out of spec shims after having been without a truck for a week at least... so I just didn't do the valve job. ughh, with that rough idle... maybe I should have.
But, it all starts with a compression test, I know, I know, I need to do this still. to really determine whats what.
In all, lots to do. figure pulling that engine allows me to do the valve job, but shoot, if I have that sucker out and on an engine stand I might as well remove the heads and do a full service on the top end and replace the head gaskets. but then what about the block, it's out, my trucks in shambles for over a week at this point, might as well hone and rebuild the bottom end too. but hot damn I never wanted to trouble shoot an oil leak and end up honing my block! things definitely escalated quickly!
in addition to all this, I need to replace the rear drive shaft carrier bearing and might as well hit that main transmission support bracket to. really firm up that drift shaft. maybe it'll stop clunking when letting my foot off the brake after a light. I had read that that was due to the zerks needing to be servied on the drive shaft. I greased all of those zerks and it still clunks. other said it was axle wrap due to the soft rear leafs but i'm starting to think it's that rear carrier bearing. I digress.
I also want to add a Bilstein 5100 lift to it with upgraded leafs in the rear. and after all is said and done, tires and rims baby! but shoot, all of this is pointless dreaming if the engine is cracked causing that damn oil leak just pass the head gaskets. in which case, buy an engine with less miles on it, swap her in, hope for the best? shoot, just bout this thing 6 months ago. if I do all of this, my friggin great grandkids better inherit this thang.... I'm 28 with no kids.
anyway, i'm new here. thanks for listening.

 

My guess would be the oil pan gasket. I would try re-torquing the bolts to factory specs first. Clean it up and see if it starts leaking again. Chances are, over the years they've probably loosened.

 

BOOOOOM! Ima try it thanks!

 

I clicked on this because I owned my 1st gen tacoma with the 5vzfe for 4 years, and encountered a few oil leaks.

First of all,

....but why though....?



Second of all - I'm sorry, but IMO the only replies you're likely to get here will be along the lines of "jeez, 360k miles, no shit it's got blown compression." and "360k miles, yeah it's gonna leak oil. Be grateful that's all you got to worry about."

Third, Yes, you pretty much have to move something to replace the oil pan gasket. Either move the front diff, or lift the engine up.
If you want to be bold, you might consider dropping the oil pan just barely enough to slip the new gasket in, but you have to cut the gasket so it can go around the rotating assembly. Your clearance between the oil pan and the front diff is just a few hairs.

But honestly, man...you really threw the wrong amount of money at the wrong truck if you're the type of guy who is worried about oil leaks.

 

fast5,
yea you right, you right. but I didn't know any better. ima learn though... one day.

 

Yep. Of course. I did the same thing when I bought my first truck. Looked at it in the dark, and test drove it down one block. Not around the block, just down, one, block.

Did ya happen to check it for frame rust...?

 

Good job on the valve cover gaskets. Honestly, if I were you, I'd buy a valve shim kit online. I'd say after 360k mi, it probably needs it. Wait awhile, see if it gets any worse then decide if you should do it. I definitely wouldn't rebuild the engine. These are known for high mileage. Also what fast5speed said. You can cut the gasket and squeeze it in that way. Lightly use "pookey" on both sides of the gasket and "glob" it on by the cut..

 

Looking at the pictures, it seems pretty clean!!

 

Yeah, you're right. I took a second look, and all the bolts look super clean. As well as the frame, but only the front part of the frame was pictured. Dude probably lives in California

 

I'd say if the rest of the truck is in pretty good shape, he got a decent deal on it. Heck the engine runs fine, if the OP gets another 100k out of it, it would be well worth the $4500.

 

no frame rust. I'm in Cali. it's clean and runs pretty well. i'm happy with the truck over all. if I can tighten down these oil pan bolts and solve the oil leak i'll be delighted. When it's hot, the starter doesn't like to turn over, just one click as it tries to turn but then decides it's not up the job. a few more turns of the key and it'll start. I read it's likely the contacts but i'll prob just change the entire starter. i'm not looking forward to taking those valve covers off again for that valve job so I will prob wait until the idle gets worse. I'll compression check it in the next couple weeks. watch em all be over 200, fingers crossed. Thanks for your help guys. I am truly honored to speak with such pro's in the world of such an incredible truck.

 

@fast5speed called it!! It seems like a great truck. Post some more pictures when you get a chance. The good thing about buying a truck that needs a "little" work is, you gain experience for your mechanical abilities.

 

Check the battery first! Could be low CCA.

 

battery first. got it. yeah I was looking forward to a little work :-D just want ot o make sure i'm doing to right work before embarking on the next project. yota nation baby. next mark, 500k mile club

 

That thing is clean!! I've always wanted the 2002-2004 era Taco's. Just couldn't justify what people ask for them in Texas.

 

Just buy the cheap contacts for the starter on Amazon Prime. It's a cheap fix. You have to pull the starter but oh well. That fixed mine and I had your symptoms.

 

Well hurry up so you can join the 500k club, I’m waiting

 

there should be no gasket on the oil pan. The oil pan should have been sealed with FIPG ... form in place gasket material. The other potential leak could be from the oil cooler, D/S of the block 2/3 of the way back. Do a search using "Mystery coolant leak found" in the 1st gen forum and you will see pictures of what I am talking about.

 

I'm very unaware of any oil cooler on these motors.

 

the pickups "should" have them but then again I have only seen CA trucks and I do not know what conditions Toyota uses when/if they are installed. The car 3.4's that I have installed required me to convert the block from non-oil cooler to oil cooler (different water pump, coolant lines and transfering of the old cooler to the new block).