Irregular idle, rusty colour/gunk in coolant

[Nakiboy79]

Hi All,

I have a nasty idle and car dies/almost dies when I engage clutch, just flushed radiator clean two weeks ago because I noticed I had rusty coloured water.. same again now but even worse. Engine oil is clean and clear.

Manual EJ20T 1998 wrx impreza stock TD04H 151,000 kms. Allowing more boost than maybe I should? (14 psi) as a result I think I may have a leak in the intake manifold? Anyone agree/ other suggestions?

[rslegy]

check for a vaccum leak

[tebbyj]

Is the ECU putting out any codes? could be many things but irregular idle is usually AFM, or air leak related.

Rusty water is common enough. Just a build up of scale in the cooling system from lack of servicing.

If you want to get rid of most of it, Drain the cooling system, Take off the thermostat housing at the bottom of the engine as well as the top and bottom rad hose.

Put your garden hose in the top tank and run it until the water coming out the bottom is clear then do the same with the rad.

Put it all back together and refill with fresh coolant. Should flush most of it out, you would have loosened it with your previous flush.

[Nakiboy79]

Thanks rslegy and tebbyj, all good advice.

For anyone who experiences similar faults the results are:

1. rough idle = aftermarket BOV needed adjustment. I am learning more about how many problems a/m BOV\'s can cause.

2. rusty coolant = flushed out forwards and backwards both with water and compressed air. Interesting to note is that when the system ran clear with water, blowing the system out with compressed air threw out about a litre of crappy water and rusty gunk. Added a rust and sludge eliminator from repco, coolant now looks jet black. Will wait a week then see how it looks. Will add about 2 litres of antifreeze if ok.

Thanks to Kim Hodge and Vogeltown Automotive in New Plymouth!