Water passages rust and gunk removal

Mike here again !
I am getting the engine ready to turn over, and have removed the intake manifold and see that the water passages are full of rusty gunk , with a view to cleaning these passages

, has anybody got a good method and /or recommendations of cleaning fluids to clean them out ?

The head is not usually a problem. If there is a problem with water circulation its usually with sediment in the bottom of the block. If you do have problems its best to remove all the core plugs and scrape out all you can. You might need to invert the block and shake it at various angles to extract the loose stuff. The 3.5 litre engines are marginal for cooling but I suspect that you won’t have a problem with the 2.5 litre.


I’ve got a running engine with the Australian inline filter sock and thermocure as discussed in previous discussions. It’s stopped the bubbling and boiling over when finished a run so some improvement. Got a few more heat cycles to go before flushing and normal coolant in

Hi Mike iv done xj6 and E types befor just with a jet washer. …ideally remove core plugs and water pump and tape up any holes you dont want water getting into…if the engine was a runner i would reccomend any of the engine flush products but you typically need to get the engine hot to get them working…Steve

I did this on my motorhome, this past summer, and it brought out all lotta junk!


Hi all thanks for all the tips, I have removed the water pump and looking down through the orifice where the pump pumps water back to the block I can see the bottom of the water channels and it doesn’t look too bad, I will remove the core plugs, get some long wire brushes of some sort and mechanically get as much as I can loosened then power wash inside best I can then use a wet and dry vac to suck it out
what can go wrong!
By the way, the link Wiggles (Paul) sent I cannot get to open, can you try again Paul, it say it must be a private or does not exist

When I first got my MK V, it couldn’t get up the hill next to my house without over heating. A friend told me to drain and flush the system, then add EvapoRust. I had to order the 5 gallon pail from Home Depot but it was only $85 (four years ago). Once flushed, I filled the system with the EvapoRust and ran the car for two months in the summer. It dropped the cars temp by 15 degrees. Once done with it, I drained and saved it. I flushed the system twice with clean water and refilled with new antifreeze. The saved EvapoRust was used in my 1930 Lasalle and dropped its temp by 10 degrees. I’m still using the mostly “spent” fluid as a bath for rusty parts. It takes a while but still removes rust from the metal parts without eating any steel like an acid would do. This stuff is amazing. It won’t hurt aluminum, seals or the copper in the radiator. Best $85 I ever spent.
Note: I have no connection with EvapoRust or its parent company. I just love the stuff!


Thanks for the tip, bought some and will use when I start her up