 OT: I'm working on an old water cooled car and have a question., Gasp. |
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| Krieger |
 Apr 6 2026, 08:41 PM
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Advanced Member  Group: Members Posts: 4,848 Joined: 24-May 04 From: Santa Rosa CA Member No.: 2,104 Region Association: None 
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I'm doing some work on a friend's 1964 MGB. It has sat for the last 5 years. Before that in 2021 after sitting for 17 years a shop got it running and driving. I don't think she drove it more than a few hundred miles lot of reasons. So I am going through each system. I'm working on the cooling system now. I drained the coolant from the radiator. I tried to drain the coolant from the engine block. It had a brass valve that was stuck so I removed it. Nothing came out! Its totally plugged. The threaded hole (about 1/2") in the case goes back an inch and makes a 90° turn. I've tried working a bent wire inside. I can get up there about an inch. Still nothing came out. With the thermostat removed and using compressed air, I can force air into the coolant drain hole and there is some bubbling happening where the thermostat was. Not enough bubbling to justify the 50 psi I put in. How can I get this flowing again? What have you guys had luck with? I was looking at Thermocure by Evapo Rust.
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Replies(1 - 3)
| KELTY360 |
Apr 6 2026, 09:06 PM
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914 Neferati Group: Members Posts: 5,186 Joined: 31-December 05 From: Pt. Townsend, WA Member No.: 5,344 Region Association: Pacific Northwest
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I’ve got no answer for you, but I do have a quick story. Years ago I was driving on a twisty road on Mercer Island when I saw an MGB in front of me. Nothing special about it till I noticed the license plate. It was a simple message: FIX.
(IMG:style_emoticons/default/lol-2.gif) |
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| Superhawk996 |
Apr 6 2026, 09:57 PM
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914 Guru Group: Members Posts: 7,771 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch
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You are on the right track.
Basically an acid dip would be done to a bare block before a rebuild. The less extreme options are citric acid flush solutions or evaporust type solution. Im not sure what EvapoRust is (MSDS says propriety trade secret) but will vouch for whatever it is it works. Would expect the thermocure product to basically be the same. Plan for extended soak time based on how clogged up it sounds. Keep digging with the wire in between soaking sessions. I would start with extended soaks before trying to drive knowing the full block isn’t getting good flow and will have hot spots where the water jacket doesn’t have coolant circulating. |
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| Artfrombama |
Apr 7 2026, 12:13 AM
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Artfrombama Group: Members Posts: 445 Joined: 21-January 24 From: One of the chosen few Member No.: 27,870 Region Association: South East States
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FWIW; Old used car salesman trick. Very dirty cooling system, dump in a box of Cascade automatic dishwashing detergent in the radiator and drive the car around a day or two. Pull off the bottom hose and flush with water.
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