Coolant flush

[Rissy]

I've been working away on my car quite a bit over the past few weeks, and will be continuing right up until just before Lotus next month.

One of the things I did was drop all my coolant. I was replacing three hose sections, both at the radiator and the 45 degree angle one at the back right hand side beside the gearbox. So this is where my coolant was dropped from initially. I then pulled the plugs on either side of the engine to release everything in there too.

While I was at it, I pulled my expansion bottle off to try and fix a leak on it.

So now, before I reinstate my bottle, I was thinking of doing a complete flush through with the garden hose, since the system has been open to atmosphere for weeks and has only a small unaccounted amount of coolant left in it (maybe 1-1.5ltrs Max).

Is it possible to squirt water down the expansion bottle hose and expect water to come out of the water jacket plug on the RHS of the engine, or does the pump need to be turning for that to happen? (Presuming that this entry/exit choice would allow a complete system flush? (If not, then how?)

Thanks.

[Chris Williams]

Should flow past the pump with no issues, however I would supect the thermostat would be much more of an issue. I know form when I have done similar I just removed the plugs from the block on either side and just kept flushing with high pressure water as best I could then allowing it to drain.
Chris

[DMCTodayMichael]

Although I have done it that way in the past (on another car) I would stick with coolant with a coolant flush additive mainly so the waterpump will stay lubricated properly. Once you drain the coolant and flush additive, replace with distilled water and coolant mix.

[Rissy]

Cheers for the info chaps.

I finally got to a point where I could jam the hose down the pipework for a flush. I removed both water jacket plugs. With both removed, water certainly came out both almost straight away, and brought with it, old coolant until it ran clear water, but this only took seconds. The flow wasn't very energetic from either side of the engine either, more of a rapid pour than a gush.
I know this hasn't flushed around the pump or the upper pipework, but I have to presume they are empty anyway, since all the fluid will have drained downwards and out. So, although it's not what I considered doing, or it to be like, I've got to hope that it's good enough. I got my 5.5ltrs worth of coolant in the system after the flush and reinstating my expansion bottle (since it had been taken off for repair to hopefully stop it leaking), but just this much new fluid took the level to over half way up the bottle, so until I've got my front suspension rebuilt and the car back down on to its front wheels, I'll have to wait until I can put my 5.5ltrs worth of water into it, gradually, while turning the engine over and bleeding the system.
I'm still at least a couple of weeks away from this point yet.