Cleaning 'Block' Coolant Passages While Head is Removed?

[Zambuzan]

So I'm currently getting my head/valves cleaned and refreshed by a machine shop. While it's off, is there a way to rid the coolant passages of rust and debris? Naturally, the block is rusting and discoloring due to it sitting outside (installed in car), and I would hate to install a fresh head just to have it circulate rusty coolant. Obviously I will flush it with distilled water a few times post-install, but is there anything I can do in the mean time?
Thanks.


Forgot to mention: all cooling items are new(radiator, hoses, water pump, etc.), would hate to recirculate rust in the radiator!

[15Michaeljoseph]

You might be able to put the old pump back on and back-flow it with a garden hose? Something like that? Sent from my moto g(6) using Tapatalk

[Zambuzan]

You might be able to put the old pump back on and back-flow it with a garden hose? Something like that? Sent from my moto g(6) using Tapatalk

I was thinking about pressure washing through the water pump hole, but not sure how well that would go haha (hydrolock??). I think I'm just going to use a radiator flushing substance after I install the head. Will flush it until clear water comes out.... Been reading around and it's been advised to remove the thermostat to speed up the process... noted!

[15Michaeljoseph]

I was thinking about pressure washing through the water pump hole, but not sure how well that would go haha (hydrolock??). I think I'm just going to use a radiator flushing substance after I install the head. Will flush it until clear water comes out.... Been reading around and it's been advised to remove the thermostat to speed up the process... noted!

Yeah, I wouldn't quite be worried about hydrolocking if some amount of water somehow got into the cylinders, however it's probably a mess to deal with afterward regardless and probably not the best option. I don't think any of the cooling passages would be affected by the kind of rust you're describing, unless it was bigger flakes floating around in there... Run it and do some drain and fills, toss in a cleaning agent perhaps. After I did my head gasket, I had some gasket debris/ tiny scotchbrite fuzz end up going down into the coolant passages of the block. Did a block and radiator drain and fill after reassembly/ running, and I feel pretty confident in that. Don't forget to use BMW blue antifreeze! Sent from my moto g(6) using Tapatalk

[Zambuzan]

There definitely was some flaking when I drained the coolant, though minimal. There was also rust-colored residue left on the hoses. I guess I'll attribute that to the green coolant that was in there... I don't know.

How clean should the block be, to accept the new head gasket? I thoroughly cleaned mine with brake clean, scotchbrite, and a razor but it's still fairly stained.

Don't forget to use BMW blue antifreeze! Sent from my moto g(6) using Tapatalk

Already bought Prestone European! It's at least a shade of blue...

[roguetoaster]

There definitely was some flaking when I drained the coolant, though minimal. There was also rust-colored residue left on the hoses. I guess I'll attribute that to the green coolant that was in there... I don't know.

How clean should the block be, to accept the new head gasket? I thoroughly cleaned mine with brake clean, scotchbrite, and a razor but it's still fairly stained.



Already bought Prestone European! It's at least a shade of blue...

The residue was probably deposits from tap water or degraded coolant over time. Likely not a problem to run just about any coolant as long as the system is clean before filling, and distilled or otherwise mostly mineral free water is used.

Staining on the block is fine, but flatness is key. Take a reliable known flat surface and run it across the block. Feel for imperfection, look for obvious height differences from multiple angles.

Not advocating it, but some people use spray gasket material or non setting gasket sealant/maker when they have a surface that may be slightly less than machine shop fresh.

[Zambuzan]

Not advocating it, but some people use spray gasket material or non setting gasket sealant/maker when they have a surface that may be slightly less than machine shop fresh.

My block surface still has a few sticky residues from the previous HG, but I'm exhausted from cleaning it. I will be using copper spray on the HG, can't hurt.

Thanks for jumping around threads to help out!

[15Michaeljoseph]

My block surface still has a few sticky residues from the previous HG, but I'm exhausted from cleaning it. I will be using copper spray on the HG, can't hurt. Thanks for jumping around threads to help out!

I used copper spray on my HG too... No issues at all. Can't say if it's helping or not but it doesn't hurt! Sent from my moto g(6) using Tapatalk