It sit for quite a while. Now when i turn it manually by hand, it makes this noise, only when one piston retracts.

Could it be non lubricated piston rings?

I already tried spraying some WD40 into the cylinder.

Sparkplugs are unscrewed

SOLVED:
Its most likely the sound of the crankcase breather

I took my Chevy 350 to the block. It was seized from water entering through the intake. Please note, I have zero experience as a mechanic, so everything I learn to do I learn through YouTube.I was able to un-seize the motor, I honed the cylinders, replaced all the vaulves, seals, and push rods, cleaned the heads and block, and reassembled with all new fresh gaskets.

Then, I put on a brand spankin new AVS 2 Carburetor, and then I started it. It started pretty good and it sounded pretty good and then after maybe like 10-15 seconds after sounding real good, it turns off and fire shoots out the carburetor (see attached video for reference). What is wrong with it and what should I do next to help fix this?

Maybe somebody knows where this rattling at the beginning comes from? I checked the timing chain and it had no play at all.
It appears at every cold and warm start but not at a instant restart.

Slk 200 r171
M271 Kompressor
2006
150.000 km

Sorry for the bad pictures. Saw this little engine covered outside but rotting away. Probably there for a really long time. Could not see any markings or codes without moving a lot of heavy stuff. Thank you for your help!

Found this beautiful cutaway of an inline 4-cylinder engine. Seeing the pistons, valves and crank mechanism exposed like this makes understanding the 4-stroke cycle much easier. The mechanical engineering inside these things is seriously impressive.

Quick question, can I use this kind of Bardahl oil for my Saab? (Second image is the car's service manual, tell me if you need translation).

Currently I'm using Shell Helix 10w-30 full synthetic oil to flush the freshly rebuilt engine and for the break in, because it's cheep.

At the third oil change (1000 Km) I wanted to switch to Bardahl 10w-40, but honestly I don't understand any of that API SN SF stuff so idk if it'll be good for the engine on the long term.

Please help, thanks!

Hey everyone,

CAR:
2011 XC70 T6

I’m needing help manually cranking my motor from the crankshaft. (I am doing a b12 piston soak and wanting to manually turn my motor to let the chemtool get inside the rings easier)

I have the passenger wheel and wheel well liner off and can’t seem to find the crankshaft

If someone could please help me I’d greatly appreciate it.

I’ve done quite a bit of research but havnt any direct answers and there isn’t really imagery or documentation online for this transversely mounted inline SI6

Here are some images of what I’m thinking might be my crankshaft??

https://imgur.com/a/B9tp3e6

Recently bought a 2013 Honda Pilot (J35Z4 engine - 3.5-liter, 24-valve, SOHC i-VTEC aluminum-alloy V6 engine) with very low mileage. Had a photo taken with the valve cover off to do a valve cover inspection. For those of you knowledgeable with cars, how do you find my engine valves? Does it look good? Anything to watch out for?

Why is the bottom side reddish-brown vs the top side? And any idea what that strip of lime green in the middle is?

Eolic frontside.

I am experiencing a cold start studder, has trouble maintaining rpm on the start up sequence almost stalls.. No codes/ghost codes. Im thinking carbon build up or leaking injectors. Never replaced spark plug and coils so starting there. I bore scoping the pistons but have realized I have no context for what im seeing and AI just seems to corroborate w/e I am saying. This is cylinder 2. Ill reply with more when I can work the spark plugs out. They are gritty and im babying them.

F15 2017 x5 xdrive35i n55 engine 100k miles

Hey folks, my 1980 ski supreme has a 351w and was dripping at one of the venturis. Decided to tear it down and found that somebody put RTV on the gaskets. Any ideas for the best gentle way to clean the mating surfaces? Is razor blade too risky?

Also, I would expect that dripping out the venturi is a float issue. Anything else to check?

I haven't noticed this until today, but when I was cold starting, I heard this knocking sound. Is this normal? If it's not normal, is it something I should be concerned about? Would I need to repair it? It's only at ~97k miles.

I know my tire looks bad, that's not the point.

Is this the tappet noise? Or is it the cylinder block not being well oiled enough?

I got this bike from a friend to use it for a while, He is gonna beat me up gng 🥀😩

Hello, I bought a Mazda 323F BG 1990 with a 1.6L 16 valve engine. As of a few days ago, the car started leaking oil and after a quick evaluation by a local mechanic he concluded that the head gasket might be leaking. Given how quickly this can turn expensive, I instinctively started looking at everything else but the head gasket. Exhaust doesn’t produce any fumes, car idles and runs smooth. I would greatly appreciate any input and I am prepared to provide more info or pictures if needed. Thanks in advance.

2004 1GR-FE, V6 4.0L

Around December of last year I noticed a little hiccup/misfire on start up. No codes, just sounded like ole girl clearing her throat in the morning.

I’ve been getting into DIY work, actually sort of growing a decent interest in mechanic work, especially on these 4th gens because they’re straight forward and rather simple machines

Welp, I’m in the middle of doing a suspension refresh, just knocked out the rear shocks, was planning on doing the front struts

But this pending issue got me to run more tests. I use OBDFusion with a VeePeak+ that runs through my CarPlay so I can get a live feed of the data

I’m loosing coolant very slowly (2 cups in a month or so) so it’s holding but no external leaks

I knew the issue I just didn’t want to accept it. Did a coolant pressure test and it passed, held 17.8ish PSI for an hour. So that was good but then bought a cheap borescope off Amazon and checked cylinder 3, low and behold, small pool of coolant in the combustion chamber. I opened up and looked into cylinder 5 as a control and it was perfectly dry. Only happens after a cold soak and barley misfires on start up, misfire counter counted 8.

It’s at 227,700. I’m pretty strongly against stop leak products. Some say replace the motor, few say do the job. Some mechanics say just keep her rolling until judgement day.

Straight up, I’d like to learn, i absolutely love this truck, I don’t think I’m going to call it and go for another vehicle. Frame is rust free, transmission is in good shape, I’ve done a decent amount of stuff to it in the 2 years I’ve had it.

Just curious y’all’s perspective and what may be the best course of action from here. A headgasket job is obviously a big bill, but a motor swap and or stop leak come with unpredictable variables. Opening the motor could lead to unexpected obstacles and leave the truck disabled for longer than planned, it’s my daily

Thanks for your time

Hello everyone! I'm trying to ID the engine in my new 1968 Ford F600. I've done a lot of googling, and have checked all the locations for casting numbers/ID tags suggested in various forums with no luck (well, everything I could do without removing/disassembling the engine). If anyone could give me pointers on where to look for casting numbers, I'd really appreciate it. I could provide more photos as well if need be.

I was looking at an XF R-Sport with a 2L Petrol Ingenium engine (20t) and just had a physical inspection today. The car seems all fine, except this one sound that's to note as per video.

Is this rattling? Would this be the timing chain that requires replacement? Or is this how that engine generally sounds?

Edit: Vehicle year - 2018 Mileage on ODO - 80000 miles

Physical inspection - No leaks or cracked parts, everything seemed fine

Has been serviced every year until July 2025 (every 10000 miles), but oil level when checked now was just above the 1st dot (minimum level) - requires service this year

Would love some advice. Thanks!

Is this engine shot? I drained the oil & found that it had a lot of gasoline in it. Refilled with oil, started it & this is what I got.

This bike worked great for like two weeks before it started struggling, I'll explain at the bottom.

So how the engine starts: the bike has a clutch on the left handed side, and you need to pull it back to use the pedals, and when you pedal to about 10 mph or higher you can drop the clutch and the engine normally would start, and then you can use the throttle on the right handed side to control the speed, both sides have brakes.

It has a small copper colored bar on the right handed side that when pulled up helps the engine start cold, and has a fuel control (sorry for the bad discrimination I'm going off what I've been told by my stepdad who bought it used and gave it to me.)

The problem is: after reaching a speed (it changed over the course of a few days, going from 25-20-18- and just kept getting lower). But when you hit that speed the bike would stutter and slowly stop taking throttle and start slowing down, but it was still getting throttle? Like you pull the clutch that should make the engine stop pushing the bike forward, and it makes the sound that happens when you pull the throttle.

It even sped up a bit today, it went from 19 to 20 mph before going back down.

Conclusion: I don't know what's wrong with it, my stepdad has no clue what's wrong with it, the only thing that's happened was it was knocked over a week ago and that started the problems but we can't find anything visually wrong with it.

Sorry for the long message, your rules said no low effort posts and I wanted to give all the information I know. Someone please help.