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1994 Blazer no oil pressure


venom077's Avatar
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12-08-03, 01:29 AM   #1  
venom077
1994 Blazer no oil pressure

1994 S-10 Tahoe Blazer
4 door Automatic
4.3 Vortec v-6

I think my shadetree mechanic needs help. The blazer in question has a severe problem with oil pressure. It starts at about 40-50 but after no time at all it drops to nothing(no time at all being like 1-3 minutes). We have replaced the following parts

oil pump
oil sending unit
Camshaft
Camshaft bearings

there also seems to be a knock from the top of the engine once the oil pressure drops enough for the light to go on

The mechanic is a friend of my fathers and he wants me to take it back to him this weekend(for the third time!)

I was just hoping for some input so that I can get a working Blazer back this time

 
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carguyinva's Avatar
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Join Date: Nov 2003
Posts: 1,147
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12-08-03, 06:02 AM   #2  
real diagnosis

i can understand your sense of loyalty but...at some point you need your vehicle fixed and preferably without doing MORE damage in the process. It sounds like someone has just been going down the list of most likely to least likely hoping to get a bullseye and that can be VERY expensive. what needs to happen here is to really diagnose this thing. Several things come to mind...to start off with the complaint should be verified with a mechanical guage, not the vehicle guage. Assuming that the oil pressure IS really low then you must start at the source which is in the oil pan...did the mechanic reuse the old oil pump pickup? it should be replaced with the pump. what about the oil pump drive? was it inspected? it should be at this point...have him remove the distributor and get a good look at it. Tell us how this vehicle has been maintained...regular service? if the pickup and drive are ok and the oil pump has been replaced (no small job if this is a 4WD) then this would indicate an internal leak. one way to find an internal leak without complete disassembly is to fashion up a pressurized vessel (that would work like a pre-oiler) and pressurize the lube system and look for where oil is POURING out. This engine has a balance shaft under the intake...did he inspect this carefully when doing the camshaft/bearings? (why anyone would just take a shot and replace a cam is completely beyond me)...barring doing this (pressurizing) it looks like a logical disassembly needs to take place and IMHO, I'm not sure your dad's friend is the guy that ought to be doing that...perhaps it's time to "let" him off the hook and get someone a little more methodical to have a look. i'm not sure i haven't muddied the water here...good luck!

 
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