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240 Oil pressure light then instant seized engine

thesilverbrickpdx

New member
Joined
Sep 22, 2020
Location
Portland OR
I was driving home from work yesterday in my 1991 240 wagon when my oil pressure light came on and my car instantly died. All dash lights came on but the engine won't turn. Then oil light has never come on before while driving, this was a first. Oil is at the normal full level on the dipstick.

I just bought the car a month and a half ago and have always been able to see the camshaft from the oil fill cap. Is this normal? I figured the oil had settled in the pan and would flow up while the car was running, but now I'm worried its been running gunked up for who knows how long.

I'm hoping its just a blown oil pump or a clog. Does this sound right to anyone? I'm really hoping my engine isn't shot :help:
 
So the engine won't turn over with a socket on the crank pulley to turn it over? If it does still move then it seems very likely to be a timing belt as suggested.
 
The engine won’t turn, or the engine won’t run? If you can crank the starter and see the fan moving you probably broke the timing belt. That would make the oil light come on almost instantly and the engine would shut off instantly.
 
ANd it's normal to see the camshaft through the oil cap. There isn't all that much oil up in the valve cover, and it quickly and freely drains back down into the bottom of the engine.
 
And unicorns vs. horses - it's probably a timing belt. It's unlikely that a motor would suddenly seize and stop due to oil starvation, unless you stared at that oil light for... a .... bit.... longer. Absolutely NO oil pressure can start to damage things pretty damn quickly, but it still takes a bit of time to grind it to a complete halt.
 
And unicorns vs. horses - it's probably a timing belt. It's unlikely that a motor would suddenly seize and stop due to oil starvation, unless you stared at that oil light for... a .... bit.... longer. Absolutely NO oil pressure can start to damage things pretty damn quickly, but it still takes a bit of time to grind it to a complete halt.

It's the timing belt, I just pulled the cover off and the thing is shredded. I'm guessing the belt going caused the oil pump to stop turning which triggered the oil light? Is there any potential damage to the engine after going through a blown belt?
 
It's the timing belt, I just pulled the cover off and the thing is shredded. I'm guessing the belt going caused the oil pump to stop turning which triggered the oil light? Is there any potential damage to the engine after going through a blown belt?

The belt turns two things - the camshaft up top, and the 'intermediate shaft' partway down the motor. That int. shaft spins the distributor (on a 240) and turns the pump.

When the belt breaks, the oil pump immediately stops, and you'll get an oil light pretty quickly. The motor also immediately stops running, but it will spin down and stop too quickly for oil starvation to cause damage.

Replace the belt, you should be good.

Well, while you're looking at it, try turning the camshaft. It should bind and release as it pushes valves open. It shouldn't be stiff and hard to turn all the way around. Sometimes belts shred because the cam seizes up, but again, that's not all that likely if the engine had oil in it. Most likely thing is still just that the belt was way past replacement date.
 
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The belt turns two things - the camshaft up top, and the 'intermediate shaft' partway down the motor. That int. shaft spins the distributor (on a 240) and turns the pump.

When the belt breaks, the oil pump immediately stops, and you'll get an oil light pretty quickly. The motor also immediately stops running, but it will spin down and stop too quickly for oil starvation to cause damage.

Replace the belt, you should be good.

Well, while you're looking at it, try turning the camshaft. It should bind and release as it pushes valves open. It shouldn't be stiff and hard to turn all the way around. Sometimes belts shred because the cam seizes up, but again, that's not all that likely if the engine had oil in it. Most likely thing is still just that the belt was way past replacement date.

Thanks dude that makes a lot of sense. I'm assuming it's a super old belt...it's shredded so bad there's little plastic strings inside the dust cover :oops:
 
If you try to turn the cam as suggested. DO NOT turn the cam by the center bolt that holds the sprocket on. You may damage the cam.
Can you elaborate on this? Are you just saying that if it's seized and you turn/reef on it clockwise (from the front) you could strip the threads in the end of the cam?
Just asking because I have done that before since the bolt torque is higher than the turning torque of the camshaft.
 
Yeah, I've always used a wrench on that bolt to turn cams around to align them for a TB install. You're not using much force to turn them.
 
definitely going to!

I get the impression you're a bit of a newbie to car repair (we all have started there).

Replacing a timing belt is not as simple as replacing an alternator belt: a lot more is involved.

You should familiarize yourself with what is involved before deciding whether to attempt to repair it yourself or have a pro do it.

see: https://www.google.com/search?ei=gV...ient=psy-ab#kpvalbx=_llhrX43TI4Kd-gTp8K_ICg34

and

http://www.swedishbricks.net/700900...l#Engine: Seals, Belts, Crankcase Ventilation
 
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