I have a SBC 350 in my Fleetline. I've had no problems with it until Friday. I drove it to town during my lunch hour and noticed it was getting kinda warm, almost 200 degrees. It had never gotten over 170 before. I had a 160 thermostat in it. I stopped to get some gas and noticed at idle in gear, I have very low oil pressure. When I tach it up, it would come back up. So, I didn't think much about it. After getting gas, on the way back to the shop, the temp got up to about 220 and oil pressure was 0 at idle in gear. So, now I'm freakin' out. Saturday, I changed my oil pressure gauge to test it again. At cold start up I have 60 psi at idle in park. At 180 degrees oil pressure dropped to 25 psi at idle in park. Eventually, it reached 220 degrees and 0 psi oil pressure at idle in park. Thats when I shut it off........ Today, I removed the thermostat to see if maybe it was just sticking. But that wasn't it. It is still doing the same thing. The motor has no knocking and the oil pressure always comes up when I accelerate it. I first thought it's probably the oil pump. Even though it's new, that doesn't mean it's good. Several people have mentioned cam bearings could cause my loss of oil pressure. With loss of oil pressure, I guess the more friction would cause more heat, thus, the overheating. So, somebody help me out. Anybody ever experience this type of problem or have any suggestions?
what brand of guages and how accurate do you estimate they are ...... Try a cooking thermometer in the core of radiator for a test.....also a 180 degree thermostat is what you need instead of that one. On the oil pressure I check it at the port at distributor and then at the plug at timing cover and possibly even at the one above oil filter if it has that ...... It is possible the port is obstructed with some particles of sludge- Also It's rarely possible on a small block chevy to have that low of oil pressure reading for even a -SHORT- span of time without hearing [and KNOWING ] you have trouble.......
I looked in all my manuals,and from past experiences.All of what the others say are good possibilities. I hope no damage was done to your bearings. At this point,I would try a new oil pump,and hope for the best. I suspect the bypass relief valve in the pump,is opening at too low of pressure,or there is a leak somewhere in the system. good luck Seabass,I m crossing my fingers Sparkx
The motor has roughly around 30K miles on it........ I had 10W30 Mobil 1 synthetic in it until Saturday. I also changed the oil to see if that would help. I put 15W50 Mobil 1 synthetic back in it. Didn't do any good ......
The gauge I originally had on it was a new Autometer (classic) same as the rest of my gauges. I tried a new Sunpro gauge Sunday. They both read the same. 60 psi when cold and 0-5 psi at 200-220 degrees Other people have suggested a 180 thermostat. I have always used a 160 in all my motors I've put together with no problems. I have one in my truck right now and it does fine. I guees I could try a 180 and see if it makes any difference. I think its kinda odd to have both problems to occur at the same time. I'm thinking my oil pump is bad. It still under warranty, and will only take a couple hours to change........ If that don't do it, I guess I'll just pull it and put all new bearings in it ........or drop another motor in it so I can keep drivin' it while I rebuild ........
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