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So I bought an '88 Beretta GT a few months back that had been sitting for awhile, but the engine is a '90 3.1L MPFI with only a little over 2,000 miles on a COMPLETE rebuild and all new externals/internals and accessories. Guy I bought it from had the receipts to prove it and you can tell. Shortly after getting it and changing the oil, etc. I started DD'ing it. It ran fine for a week or two then one day just shot up to almost full hot. I pulled over let it cool, checked it out. Fan was working, t-stat acted stuck. Put a new 195* T-stat in it, same issues. Running warm though not full hot. Maybe 3/4 of the way up the temp gauge. So I flushed the sytem.....TWICE. Radiator is new, t-stat is new, oil change is fresh, hoses are new, I replaced the water pump with a brand new one. Heater core is good to go as well. Heat and A/C work great , no leaks or clogs. I even hosed out the fins on the condensor and radiator, just in case. Now I haven't pulled the rad and done a reverse flush with a garden hose. Short of that and pulling the heads I'm at a loss. No oil in my coolant or vice versa. I have burped it several times and seen bubbles coming into the overflow almost every time. I'm starting to wonder if it's a headgasked compression leak.
NOW....here's the rub. The faster I go , the more air gets pushed over the Rad, the faster it should cool right? Wrong. Not with this car. The faster I go , the HOTTER it gets. Slowing down to under 45 MPH or under cools it down. With this in mind, and the fact that the last two weeks I'm noticing after the engine is warmed up my Oil Pressure is dropping to zero at idle in gear, I'm starting to lean towards a weak oil pump. My pressure is good cold, and as soon as I hit the gas AT ALL when it's warmed up , say from a stop light, the oil pressure jumps right back up. I had thought a bad sending unit as it randomly pegs full out for no reason , stays and then goes back to working. I'm thinking weak oil pump because if not enough oil is getting to the lubricated components, then going faster resulting in higher operating temps makes sense. I think I'll put a high flow in it. 20% more flow than stock. Also, I pulled my PCV filter and I see very little oil flowing through the valve covers. I've stopped driving the car until I get the pump replaced at the least.
I should note I started running a solid grill just before the first incident. I took it out and started running an 'egg crate' Beretta grill which is basically the same as no grill because it lets TONS of air through.
I need some help here guys. Don't know if you would need it, but here's a shot of the engine bay. 2.8 Upper Plenum on a 3.1L. Guy I bought it from said he did that for a "sleeper" effect,lol. But I ran the block casting ,head and LIM numbers. They all came back to a '90 3.1L.
NOW....here's the rub. The faster I go , the more air gets pushed over the Rad, the faster it should cool right? Wrong. Not with this car. The faster I go , the HOTTER it gets. Slowing down to under 45 MPH or under cools it down. With this in mind, and the fact that the last two weeks I'm noticing after the engine is warmed up my Oil Pressure is dropping to zero at idle in gear, I'm starting to lean towards a weak oil pump. My pressure is good cold, and as soon as I hit the gas AT ALL when it's warmed up , say from a stop light, the oil pressure jumps right back up. I had thought a bad sending unit as it randomly pegs full out for no reason , stays and then goes back to working. I'm thinking weak oil pump because if not enough oil is getting to the lubricated components, then going faster resulting in higher operating temps makes sense. I think I'll put a high flow in it. 20% more flow than stock. Also, I pulled my PCV filter and I see very little oil flowing through the valve covers. I've stopped driving the car until I get the pump replaced at the least.
I should note I started running a solid grill just before the first incident. I took it out and started running an 'egg crate' Beretta grill which is basically the same as no grill because it lets TONS of air through.
I need some help here guys. Don't know if you would need it, but here's a shot of the engine bay. 2.8 Upper Plenum on a 3.1L. Guy I bought it from said he did that for a "sleeper" effect,lol. But I ran the block casting ,head and LIM numbers. They all came back to a '90 3.1L.
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