Bleeding V6 Cooling System - Alfa Romeo Forum
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156 2.5 V6

Bleeding V6 Cooling System

I have recently been suffering with a hot running v6 so I have now replaced the radiator and the thermostat. I also thoroughly cleaned out the aircon radiator to give good airflow through it. But it is still running a bit hotter than I would like and hotter than I remember it running when I first got it. Down the motorway at 80-90mph it is sitting at 95 but heading towards 100degC. It also tends to climb quite high if I do any hard acceleration even if it's just through the first three gears.

My main question relates to checking for any airlocks. I have released air from the top hose between the thermostat and radiator. I have released air from the radiator bleed screw on the opposite side to the top hose. I have released air from the bleed screw on top the steel pipe behind the rear cylinders. Is there any more bleed points I have missed or any special procedures I have not carried out. I thought there may be some bleed screws on the cylinder heads as the tops look higher than the coolant outlet but I just don't know. There is 4 allen headed screws on the cylinder heads (one in each corner in the middle of the vee) which I thought might be bleed screws but I am not touching them without knowing for sure what they are.

Any help would be very much appreciated as I am getting paranoid staring at the temp and I am driving like a grandad which is not good for an ALFA.

1999 156 2.5 V6 SP3 Veloce Proteo Red 17" 15 Spoke White Alfa Alloys Eibach Pro Kit Springs/Dampers Powerflow Stainless Exhaust
Tesbadu is offline  
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Hi i have the same car 98 v6 never overheats in 30 plus degrees. Have you tried the two sensors,Water temp sensors or have them checked with OHM meter.A dealer should be able to plug in the OBDII port to get a fault code.Maybe a higher combo of coolant to water.Try opening one of the valves to rad and squeeze the upper and lower hoses to see if that releases some air bubbles,though i doubt that would cause overheating.Are both fans turning on with a'/c on? Good luck vince
Bondiins is offline  
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Hi, the service book does not mention any bleeding at all when it comes to changing coolant. Just "Supply the engine cooling system with the recommended fluid". But diagnosis for high engine temp with fan operating: 1. check coolant level (sorry but of course its the first point) 2. engagement of cooling fan, engine oil level and quality, water pump drive belt. If all OK: connect diag equipment (PC w/Examiner) and read engine temp value and compare with instrument reading.
next: -check for air bubbles in the expansion tank.
next: check cylinder head tightening and gasket seal.
next: check thermostat
next: pipes for obstructions, hoses etc the plumbing in general incl radiator
next: water pump and gasket guess is to check the instrument read compared to Examiner. It might be that the read out is not the same as the actual engine temperature. Or rather lets hope so!

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