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4.9 anti-drain back valve


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I just changed the oil in my 92 STS and when I took the oil filter off there was a small valve assembly laying on the top of the oil filter. I removed the oil filter adapter and found that there are 2 of these in the adapter--a big one and a small one. The cadillac service manual calls them both valve assemblys. It appears to me that the bigger one is the by-pass valve and the small one might be some kind of anti-drain back valve. I could not reinstall it because it was crushed. I can only assume this happened when I put the oil filter on the last time I changed the oil. Now for my question. Can I drive the car without it installed until I can order a new one and in fact do I need to replace it at all. I will have to buy a new adapter --over $100 Cdn. Thanks for your help---Roger

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I don't beleive the damage occured while removing or installing a filter.there was a failure somewhere for this to occur.I would replace the housing to be sure everthing works as designed.I replaced mine due to a crack last summer it was quite an easy job to do, remember to buy the o-rings for the 2 oil lines that connect to the housing.The 2 o-rings for the housing are included.

BTW don't over tighten the pipes and housing as you will crush them and have a premature oil leak.BOLT TORQUE is 14 FT LBS

good luck

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