Lexus is250 2009 | Smoke From Serpentine Belt Area

[dry loom]

Yo someone please help me wtf is this smoke 😭 happened after I needed a jump start from having my hazards on for 2hrs

[dry loom]

☹️

[glad apex]

@dry loom What does it smell like? Burning oil, rubber, or melting electrical wires?

[dry loom]

Not oil

[dry loom]

More like a burning plastic kinda smell

[glad apex]

Since you are saying it happened after you jump started it, I'm wondering if it may be the alternator. I think it is that general location, correct?

How many volts do you have showing on your battery?

@dry loom Also, has that difficult starting always been a problem?

[dry loom]

No it's been a problem ever since I had to jump start my car

I just got it fully charged so it was like 18 or something

And yes it is the alternator section

Do you know what this part is? @glad apex

It looks like its coming from that screw

[stable grove]

GG @dry loom, you just advanced to level 1! Chat more to level up and earn top roles!

[gloomy turret]

Is this view from the top or bottom. Hard to tell

[dry loom]

The top

[glad apex]

I sure don't. Ive been hunting, and cant find a reference to it yet.
For others @gloomy turret to help, this is what the OP is pointing out I think.

[dry loom]

YES! Thank you for such a clear photo

[glad apex]

@dry loom Looks like it is the oil canister, with filter inside...

There is a removable panel just under it that you could pop off and get another view from there.
https://www.youtube.com/watch?v=zKlGrIdrGOo

[woeful dock]

Looks like the belt is slipping due to the high alternator load.

[gloomy turret]

Possibility for sure

[gloomy turret]

Yeah I figured but wow what a photo lol I fell asleep last night researching it

[dry loom]

Yeah guys I’m gonna try to change the oil filter and get a clean batch of oil in there and see if the smoke stays!

I am also going to change the serpentine belt bc I think it got contaminated with the oil

Thank you guys for the help! I had no idea what that part was but it makes so much more sense now

[woeful dock]

I dont understand how a oil filter can smoke without spewing oil everyhwere

[dry loom]

Because it isn’t a massive hole it’s a leak

It’s a lot of steam

[woeful dock]

You can have oil leaking though the space between the copper and the insulation of wires. If there was any type of leak at the oilfilter you would see a puddle or a mist of oil.

Oil does not cause "steam"

A loose/worn belt would also explain why it started smoking after a jumpstart. The alternator is under a higher load than usual. You also said it smells like plastic.

[dry loom]

I’m not a reliable source for the smell

It just smelled like something burning, which could have been plastic but then what plastic would it have been

Obviously oil doesn’t cause literal steam, but when oil residue hits a hot metal surface it will make smoke that looks like steam

The smell was probably the serpentine rubber actually

Light oil seep + belt stress load = smoke

[woeful dock]

The filter is located underneeth. There is also no visible oil residue in the video

[dry loom]

YEah but the visible part has the filter canister cap and O ring

[woeful dock]

But no oil

[dry loom]

because it vaporized

[stable grove]

GG @dry loom, you just advanced to level 2! Chat more to level up and earn top roles!

[dry loom]

what do you mean

it’s right next to the belt it’s a high heat zone

[woeful dock]

Nope. Oil condenses, if it was oil mist everything in that area will be covered in oily residue.

[woeful dock]

1. Belt is not supposed to be hot.
2. Oil in an engine does not get hotter than ~110c.
3. This is a coldstart, you said it has been sitting for 2h.

[gloomy turret]

OP, can you start the car with the serpentine belt off?

[woeful dock]

Easer to check serpentine condition and tension.

[dry loom]

I am going to investigate the oil canister area first then remove the belt yeah

[dry loom]

oil condenses at lower temps, but near pulleys and metal surfaces under heat and motion then of course a small leak or thin film can vaporize without pooling, ESPECIALLY if it got hit by a high load jump start after sitting. even with a light coating of oil it can slip and burn from mechanical friction heat, the belt is near high friction moving metal and can transfer heat to its surroundings that’s basic physics

But additionally, you can see the smoke doesn’t start until the car successfully starts

The alternator is spinning and yet the smoke isn’t there yet as seen on first start attempt

[woeful dock]

You know that the alternator is actively controlled and does not turn on until the engine is fully started.

Stop being stubborn and check the belt before you spend money on oil and a filter just to end up where you started.
Oil getting on the belt causing it to slip is not uncommon and a likely cause. But I doubt it’s invisible oil mist from a part located below the belt that does not deposit oil anywhere else. If it’s oil the leak is located further up the engine or the power steering pump.

Only place hit enough in a engine bay to instantly vaporise oil without a trace is the exhaust manifold.

If the belt is chard, glossy or cracked it’s bad. You should not be able to twist it more than 45 degrees by hand.

[gloomy turret]

So easy to test to.

Op. A few minutes and you will have the belt off..

[dry loom]

You’re absolutely right that I shouldn’t rule out the belt, but I literally am not — I’m going to inspect it first for glazing, cracks, or oil residue and test the twist tension. I’m also not denying that oil mist might not leave obvious residue in some cases. My only reason for suspecting the canister screw is because the smoke appears to emit DIRECTLY from that spot when the engine is under load, and it didn’t happen until the car fully turned on. If the belt checks out fine and isn’t slipping, then I’ll refocus on that area and make sure the oil filter and housing aren’t leaking under pressure. Appreciate the push to check the simpler stuff first, but please realize I’m investigating them at the same time. Obviously I don’t want to waste money

They’re in the same area, if there’s oil residue on the belt while I see smoke coming out of the screw then clearly there is something wrong with the oil canister correct? @woeful dock @gloomy turret

[dry loom]

I can try this! What should I look for when I do that

[gloomy turret]

Well the car will run with no belt

And if it stills smokes, you know it’s not related to the belt.

If it doesn’t smoke, it is related to the belt.

[dry loom]

Gotcha, but why would it run? I don’t get this stuff, what is the point of the serpentine belt? Is it just that the car will run for a second and then die?

[gloomy turret]

No the car will run off the battery until the battery is dead

[dry loom]

Ok that’s what I figured! I’ll try this soon. Thank you!

[gloomy turret]

While you have the belt off, check the belt for wear like @woeful dock suggested and inspect all the pulleys

[dry loom]

Mhm, did say I would do that

[gloomy turret]

A lot of the replies are TL;DR so I must of missed it lol

In my opinion, it’s belt related. The way the smoke comes off the crank pulley makes me think that

[dry loom]

I hope so! Belt replacement would be pretty easy

[woeful dock]

You should not be able to pull off the belt by hand. You need to move the tensioner and that requires a decent sice wrench

[glad apex]

I make it a habit to replace the tensioner pulley and all idlers at the same time as the belt.
Just my 2 cents.

[dry loom]

Ok!

I want to identify and fix the issue first, would it be more worth to at least do that and replace the tensioner a little after

Like let’s say I fix the smoke issue by just changing the serpentine belt, would it be fine if I were to replace the tensioner like a week or two after when I have more time

[woeful dock]

Yiu dont know whats wrong yet

[glad apex]

@dry loom You can replace whenever you like. I've just found that the smaller pulleys tend to go often enough, and at a very inconvenient times!
Just my habit to kill all those birds with one stone.

Have you measured your battery voltage by any chance?

[dry loom]

I literally just said "let's say I fix the smoke issue"

[stable grove]

GG @dry loom, you just advanced to level 3! Chat more to level up and earn top roles!

[dry loom]

If you're here to be condescending and rude, you don't need to be here.

[dry loom]

Thank you! I think given that the car is from 2009 it would definitely be a good idea to do them both now, especially since I don't know what the last owner has done to it

[dry loom]

I got it fully charged locally and then put it back on the car, but I have since disconnected it after I took the video to avoid unnecessary draining while I'm busy with finals and unable to work on the car

When I measured it it was around 18v I believe which seems to be like "overcharged" right because shouldn't it be around 12 to start

[glad apex]

18vdc is way too high. Typically at rest it is in the mid 12's and while under heavy load in the mid 14's as the alternator charges it.
Also, please.... BSSB is here to trying to help, and he has often shown insight that exceeds my own, so don't discount his advice. Your alternator is still suspect....

[dry loom]

I'm sure his insight is well above mine in terms of car mechanics, but there is a nice way to go about things

I am absolutely still suspect about my alternator, but the reason why I'm so suspect about the oil canister is because the smoke is emitting DIRECTLY from the screw

And I just got my oil changed by valvoline around 500 miles ago

To be clear though, it was only at around 18 when I got it back from the store that charged the battery. When I was jumping the car, it was around 12

[glad apex]

Yeah, leave it to quick-lub shops to mess things up! I've seen it far more times than I care to admit!

[dry loom]

I'm thinking, what if they just never replaced the oil-filter? Because now that I think about it, they never mentioned anything about it while doing the service

I'll check both at the same time when I get the time to do so on Friday

[gloomy turret]

The oil filter would just deteriorate, it wouldn’t cause anything to smoke I wouldn’t think.

[gloomy turret]

Look to see if they charged you for a filter.

[dry loom]

Also, looking at the video you guys can hear that squeak right

That is 100% from the serpentine belt or am I mistaken

[dry loom]

They did I just checked

So if I visit that filter and it's very clearly old, that would be another issue, but you're saying it's likely not the smoke issue correct (Yes I am still going to check the alternator and sbelt first)

[gloomy turret]

I’ve never seen anything oil related burn that quick unless it is oil hitting the exhaust.

[dry loom]

What do you think it could be?

[gloomy turret]

Based on the video you sent, the belt lol or something with the belt.

Belt tensioner, belt, etc etc

[dry loom]

That is what I initially figured, but I was confused on why it didn't start smoking until after the car successfuly started. From my understanding, the belt i'm looking for is still spinning in the video I sent, correct? or am I missing something

[glad apex]

@dry loom We only see two spinning pulleys in the vid.
What we cant see is this (Red arrow). And it is the general area of the smoke. If that pulley is locked up, the belt would start to smoke at that lower corner.

[dry loom]

I see, I was under the impression that if one of the pulleys were spinning then they all would

I will update you guys on Friday! and I appreciate all of the help, BSSB, Clever Old Guy and Gonzo

[dry loom]

Hello!

I changed the serpentine belt. The car started a lot easier and has started every time. However. It is still engaging the starter for a lot longer than normal, and the smoke, although it took longer to appear, is still there. It was significantly less than before, then after a few tests it was around the same amount.

I noticed that when changing the belt, it was noticeably more difficult to remove it from under the crankshaft pulley. In addition, there is a lot of heat from that area near the crankshaft pulley and the oil canister

New video

[stable grove]

GG @dry loom, you just advanced to level 4! Chat more to level up and earn top roles!

[gloomy turret]

Did you check your pulleys while your belt was off?

[gloomy turret]

Seems like something is chewing your belt.

[dry loom]

I did not but I will do so today

[glad apex]

Did you verify the pulley I indicated above was spinning freely when you took the belt off?

[gloomy turret]

Yeah sorry but you should have. You will have to remove the belt again to check

[dry loom]

Yeah all good you are correct!

I was just able to make quick work of the belt and I had limited time so I just didn’t think to do it

But yes I did check all the pulleys! I have found the culprit

The A/C compressor is not happily spinning

At least, I believe this is the ac compressor

[gloomy turret]

Hard to tell from the video but I’m sure you are correct. Judging by olds picture from earlier it’s coming from that area(the smoke)

[dry loom]

Yes, and starting the car with no belt did produce no smoke as expected

Thank you everybody for helping me isolate the issue! I will be replacing the A/C compressor and cleaning the area thoroughly at the same time

Lexus is250 2009 | Smoke From Serpentine Belt Area