Oil filter bypass valve

[superduty4x4]

What's the harm in running without one installed? I was changing my oil last night and noticed that it wasn't in there. I need the truck so I went ahead and put it back together and filled it up with oil but if need be I'll crawl my gimp *** back under there with a new filter and get the valve installed.
On that note, my truck is a 97 but has a reman motor, I thought the issues with the bypass valve falling out were all on earlier build trucks? Why would a previous owner have removed the thing?
This is what I have:

[palmetto9]

If the valve is gone it should cause the hpop reservoir to drain causin a no start condition I would think.

[superduty4x4]

Originally Posted by palmetto9

If the valve is gone it should cause the hpop reservoir to drain causin a no start condition I would think.

Negative. The bypass valve allows for oil circulation to continue in the case of a plugged filter. With the valve gone, basically what is happening is I'm getting little to no oil filtration because everything is just going right around the filter. Not real happy about that fact... and I'm seriously considering swapping in the motor from my wrecked truck since I have no idea how long this motor has been run this way. I just bought the truck about a month and a half ago...

[kanuck15]

Id do a compression check and have an oil analysis done. I can imagine the the path of least resistance is through the oil filter due to the pressure?

[alberta 7.3]

Without the bypass thingy, the oil will travel through the oil cooler header and into the engine. It is intended to protect the lube system (bearings, etc) if the filter plugs up. I agree with Joe that an oil analysis would be a good idea. I'd just throw on the spare oil cooler/headers from the wrecked truck for now, rather than pulling the engine.

[superduty4x4]

This truck needs a clutch soon anyway, so I just figured to swap motors when I swap clutches since I have an engine hoist and not a tranny jack.

[alberta 7.3]

If you do pull it, remove the crank damper, water pump, and front accessory brackets. Remove the shift lever from the transmission. You need every inch possible to get the trans and clutch separated while clearing the crossmember, then have the clutch clear the firewall and wiper motor. The FSM calls for the manual transmission to be removed, but it can be done with it in place.

[superduty4x4]

Originally Posted by alberta 7.3

If you do pull it, remove the crank damper, water pump, and front accessory brackets. Remove the shift lever from the transmission. You need every inch possible to get the trans and clutch separated while clearing the crossmember, then have the clutch clear the firewall and wiper motor. The FSM calls for the manual transmission to be removed, but it can be done with it in place.

Good to know, thanks Bill.