oil pressure and ?sludge? problem.

[87454westernhauler]

I have an 80 1/2 ton silverado with a 350 sbc and th350 tranny. have a big question  and posibly an issue with it .   Since i bought it the oil pressure gage only reads if i revit up, I thought it was just the dash gage, so I replaced the dash gage with one I know works and still doing the same thing. I just replaced the motor oil and filter with 10w30 and no change. I am wondering if the sensor by the distributor is bad or maybe something bigger?
 Another thing is that I started degreesing the motor and cleening the carb and pulled the vacumn advance out and the PCV valve to klean it and relized that it was full of white sludgy type stuff! I did pull all of the plugs on the passanger side and replaced them and they had like no oil on them, just carbon build up. I asked my dad about it and he thinks that it is antifreeze??? I am wondering if it is sludge in the oil as i didn't see and antifreeze in the old oil. could the sludge if that is what it is be blocking the oil pressure sensor or what are your guyes thought on it, cause my dad is wanting me to sell it and I would not rilly want to do that with it!!!! help and thanks guys for the help.

[Grim 82]

The sludge is most likely just from condensation moisture, and usually clings to the inside of the valve cover with the PCV valve in it. I wouldn't worry about that but check your coolant level & condition to be sure.

Try a new sending unit for the oil pressure, and clean out the pipe fitting that it threads into.

[Irish_Alley]

The white stuff ain't normal but if you were to lets say run the engine then change the oil most time it would mixed together and you wouldn't see it except where it can cling to things like the top part of the engine.  Like he said check your coolant level and see if its dropping. As far as the oil pressure like said replace the sensor the go from there. You would see a drop from a start up to running temp due to the oil warming up

[87454westernhauler]

the oil pressure seems to be the same when it is hot or cold. do you think that the sludge stuff is coolant then? i had the heater core blow out right after i got it and haven't rilly driven it since i changed the core.

[Grim 82]

Carefully remove the oil drain plug and see what pours out first. If there is water or coolant in the oil it will be on the bottom. If it's just oil, you're good to go. I suspect it's just condensation. If you remove that valve cover it will probably look like a handful of lithium grease was smeared in there.

[87454westernhauler]

ill try pulling the plug out. what I suspect is that it is just condensation, mainly because it had not been driven for about 5 years and had sat around alot not having the oil changed for over 5 years also and I plan on trying to pull the rocker arm covers off and replacing the gaskets because they leak like crazy and see if it is just condensation or sludge build up. I did shine a flash light inside the rockers through the oil fill and it looked fairly clean inn side on the head and valves. hope it isn't antifreeze!!!!

[beastie_3]

if it has been sitting for 5 years, its probably just condensation, and not a mechanical issue.

[87454westernhauler]

Ok I pulled the rockers off last night and the pass side rocker and it had white sludge stuff on the front and back of it, and the drivers side was the same but alot thicker. there was no sludge stuff on the heads just the rockers. I also pulled the rest of the spark plugs and they looked pretty good. I am going to try and drive it alittle tonight and then pull oil pan plug and see if there is antifreeze in it. I also am going to borrow a cooling system pressure checker from a buddy of mine and see what hapens with that.

[Irish_Alley]

If it been sitting for 5 years that would probably happen. Change the oil before you do start it. Also if you pull the drain plug to check for water give it a couple days to separate after running the engine the water and oil will mix and it will just been thin

[87454westernhauler]

do you guys think that the sludge is condensation or is it probably antifreeze? ill let it sit over the weekend and pull the plug monday.

[Grim 82]

Did you check the coolant level? Pull the dipstick and see if it's milky looking, and proceed with the other checks we suggested.

Right now, I would be more concerned with the oil pressure issue. I just retired my 350 this week because of no oil pressure. I hope yours is just a bad sending unit.

[87454westernhauler]

i am going to to try and pull it out tonight if i get home before dark and pull the sending unit. the oil doesn't seem to be milky and i drove it a couple of mile last night and opened the radiator after and it was full still, i am going to borrow a cooling system pressure tester from a friend of mine sunday and see what happens. Seems to sound ok when it is running, can't hear any knocks or clacking. it seemed to have a little more pressure last night when i took it for a drive than it did before i pulled the rockers off, im hoping that it is just a bad sending unit How much would i be looking at for a new sending unit/ sensor???

[Grim 82]

How much would i be looking at for a new sending unit/ sensor???

I would be surprised if they are more than about $10, and they are SO much fun to replace.

[87454westernhauler]

I got to looking at the sending unit/sensor. that looks to be interesting to change. I took it on a little/ HARD drive friday night on the gravel roads by my place I checked the anti freeze level before I started the engine, and checked it the satuday morning and it was at the same level. So I think that the cooling system is ok. 

the oil pressure seems to read around 7lbs at fast idle cold and 15 if I am reving it, but the gage flickers around alot and is hard to get an acurate reading.

Another issue. it runs ok at idle and if I am easy on the pedal. but if i step on it any under load it seems to overload and gage and cut out. I just changed the fuel filter. it strugles to hit 50 and is hard to hit 60-65 in it without it gaging. not shure if it is the carb or what. it has a 4barrel Quadraget carburator on it.