Is this the 5.0l? Look at the picture below and see if you have that valve #1. If so, make sure if there is any vacuum hoses or electrical wires going to it they are hooked up. Feel both heater hoses, #'s 4 and 6, they should both be hot. Let me know if both hoses are hot and if anything was off that valve.
If everything checks out, it may just be a faulty valve.
They list one here for $34.76, http://www.gmpartsgiant.com/Page_Product/PartDetail.aspx?&Make=Oldsmobile&Model=Custom Cruiser&Year=1986&MakeCode=O&ModelCode=B&CatalogCode=32W&mCode=3BP35&majorIndexID=08&minorIndexID=MB08-002&SortKey=58
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i am waiting for motor to warm up how ever looks like something not rigft with that valve hole in top of valve has nothing hooked to it and another short hose heads toward front of motor but not hooked to anything im going out now to check if hoses are hot ill be back with you in 5 min
it is just opposite of what you said in other words hose from water pump is cold. other hose is hot.
refering to the picture or diagram i was sent heater valve is #1 and it shows hose #6 going to it but in my case it does not. it comes out of fire wall or i guess heater core straight to rear of the block. and nothing is hooked to that place where digram shoes hose 6 going to #1 (valve) also there is a small hose out of valve that is capt off with a screw hose #6 is hot hose#4 is cold
put the new valve on no change heater still blows cold. an older retired GM mechanic tells me it might be a bad head gasket. all i know for sure is this thing is making me go nuts and broke at the same time. any other ideas?