Help diagnose an oil leak (2008 Sienna)

"BaconSandwich is tasty." (baconsandwich) 09/18/2019 at 20:14 • Filed to: Toyota, incontenance, help me obi wan, the joys of used vehicles

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Unfortunately the Sienna has decided that it doesn’t like oil, and has started depositing it on the street. After work I was able to put it up on ramps and poke around. I knew the boot on the steering rack was shot, so I was expecting to see a bit of power steering fluid leaking out. Unfortunately I think there’s two other leaks - oil leaks.

The first one is more toward the center of the vehicle. I was thinking it was on the gasket between the engine and transmission, but I’m not sure on that. There didn’t appear to be an obvious spot where it was weeping, but it was definitely collecting lower down and dripping.

The other spot appeared up behind the block, on the passenger side, up above the inner tie rod end. I’m wondering if that also contributed to the demise of the boot on the steering rack on that side.

At this point I’m going to take it in to get the steering rack done (~$500 in parts, $850 in labour), but getting the other two oil leaks sorted out before I do that would be ideal.

Any guesses on where it’ s leaking from?

Dr. Zoidberg - RIP Oppo > BaconSandwich is tasty. 09/18/2019 at 20:36

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Having owned nine of those Toyota thingie-do-bingies, here’s are my top candidates:

1. valve cover gasket
2. valve cover gasket
3. oil pan gasket
4. valve cover gasket
5. oil pan gasket
6. oil pan gasket
7. cam seals
8. check the seal on the oil filter though
9. valve cover gasket

RallyWrench > BaconSandwich is tasty. 09/18/2019 at 20:43

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That leak at the bellhousing looks slighly red in color? I’d hope it’s not a trans input/torque converter seal. If it’s engine oil, that could be the rear of the pan as rear main seals aren’t common. Can you see if the valve covers are leaking and running down? The rear bank is more prone to that. In the second pic, is the PS pump or lines seeping? Those are a constant issue on transverse Toyotas. Also, the steering rack in my ‘05 Sienna leaks too...

dogisbadob > BaconSandwich is tasty. 09/18/2019 at 21:00

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If it’s the valve cover gasket, it’s an impossible job on those. The transverse V6 is an iherently stupid design because it’s hard to work on, but Toyota does that on steroids. You have to pull the intake, which takes a whole weekend. If you do them, also replace the spark plugs (use ruthenium, so you never have to do them again!)

I love Toyota, but the transverse V6 is one of the few demerits they have

Too bad no more 4-cylinder Sienna. They only made them for a few years. That’s what I’d get if I needed a minivan

And if you get a lot of rust, and the leak isn’t too bad, I wouldn’t even bother replacing it until the leak is severe. The dripping oil coats the shit underneath, protecting it from rust.

With the amount of money you’ll be spending on the steering rack and valve cover gaskets (which could very well be over $600 in labor), you might want to consider saving up for a 4-cylinder Sienna that’s a little

If it’s the oil pan gasket, that’s not too bad, although there are a bunch of bolts on it! Just drain the oil then undo the bolts.

If it’s the rear main seal, that’s also a big job. You have to drop the engine or transmission. If it’s only leaking oil, and it’s not severe, you probably don’t have to replace it. If it was a manual transmission, then it would be more serious, since oil cou7ld get on the clutch, but for automatic, don’t even bother unless it leaks big

To do all of that, just save up for a 4-cylinder Sienna that’s easier to work on

BrianGriffin thinks “reliable” is just a state of mind > BaconSandwich is tasty. 09/18/2019 at 21:22

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Take it from a German car owner:

Evaluate the damage the leak will do if left alone. Evaluate the cost of oil. Evaluate the cost of fixing the leak. Save cardboard boxes and put underneath car. 

Michael > BrianGriffin thinks “reliable” is just a state of mind 09/18/2019 at 23:03

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Toyota though. Generally when you fix 'em they stay fixed

Dogsatemypants > BaconSandwich is tasty. 09/19/2019 at 00:04

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Could just be waste oil from the filter finding its way to ground.... that one has the metal oil filter under the exhaust manifold behind the radiator, right. It looks like you took the pics facing toward the rear. I doubt it's the rear main where engine and trans meet. In order of likely culprit i nominate, waste oil from old filter, oil pan gasket, or valve cover. Your steering pump does look a bit weepy.

Dogsatemypants > Dogsatemypants 09/19/2019 at 00:08

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If i ever meet the dickweed that placed an oil filter right underneath the no touchy parts and right next to the boily burny fanny spinny bits, ima kick his/her teeth in and twist their nipples clean off with a rusty pair of pliers.

BaconSandwich is tasty. > Dogsatemypants 10/03/2019 at 20:19

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The oil filter in this case is actually mounted fairly far down, on the bottom/front of the block. It’d have to be some pretty crazy oil to work it’s way up the back of the block that high up.

I’m thinking the steering pump could be a source of it as well.  I think I’ll end up taking it in to get a second opinion on what to do.  At this point I could get a replacement bellows for the steering rack, or I could replace the entire thing.  I don’t think I’ve seen any specific symptoms of the steering rack going bad, but even if I replace the bellows, I’d still likely need an alignment afterward as well.

BaconSandwich is tasty. > Dogsatemypants 10/03/2019 at 20:20

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If you think the Sienna is bad, the Civic is 10x worse. The filter is up on the back side of the block, beside the firewall. There’s an engine mount/bracket thing right next to it, so the oil runs down the back of the block right onto the hot exhaust. I’ve learned to replace it entirely by feel at this point, while avoiding burning my arm on the exhaust.

I think engineers that design cars should be forced to perform maintenance on them before they are released to market.

BaconSandwich is tasty. > Dr. Zoidberg - RIP Oppo 10/03/2019 at 20:21

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Dude, you’ve seriously owned 9 different Toyota vans? I thought they were supposed to be nigh-indestructible .  Was it some sort of company fleet or something?

Dr. Zoidberg - RIP Oppo > BaconSandwich is tasty. 10/03/2019 at 20:35

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Never owned a van, just referring to my nine Toyota-anythings that all leaked oil.

Dogsatemypants > BaconSandwich is tasty. 10/04/2019 at 00:54

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It can be messy as long as i dont burn the crap out of my wrist. Or have to have a second wrist to get to it. Hondas aren’t bad.

BaconSandwich is tasty. > Dr. Zoidberg - RIP Oppo 10/04/2019 at 11:48

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Ah, gotcha.

At some point it just becomes self changing oil, right? I mean, you'd still have to replace the filter, but...