VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1925 overheating

Oil pressure resolved finally with a new pump. Next is that it overheats at idle in driveway. I have not driven it farther than a few blocks so I only assume it will overheat driving also. Radiator did not seem to flow well so I flushed it with a hose and now water seems to pour out faster than you can put it in with a hose. Started it with upper hose off the radiator and water seems to gush out after a few seconds. I had seen a thread about putting a restrictor plate in so tried a temporary go at it with a washer in the hose with an 11/16 dia hole through, It made no difference. I also tried a shop fan in front of radiator and no change. Lower rad hose feels cosiderably cooler than upper which leads me to believe the radiator is doing its job. There is a crack in the top surface of head,carb side midway back and in the block half way down carb side. Someone jb welded over these and then painted the engine hiding it. I have not really noticed the block leaking but the head dribbles a tad when running till warmed up. These will have to be addressed later in another thread if the over heating problem is solved. I think it seems to run too well to scrap the whole deal. Any help would be greatly appreciated.

You could have a load of crud in the water jacket of the engine (block and head). I certainly found this to be true when I rebuilt Lurch's engine 3 years ago.

With the head off, you can root around in the water passages with a coat hanger and screw driver to loosen the rust and corrosion. Then attach a 1/2 in tube to the end of your shop vac to vacuum the crud out. I found the most buildup around and behind cylinders 3 and 4.

After putting the head back on (and before hooking up the radiator hoses), hook a garden hose to the radiator connections on the engine and flush the engine forwards and backwards (switch the input hose with the output hose). You'll be surprised at the amount of junk that comes out. I put an old t-shirt over the output hose (as a filter) so I could see all the flakes that came out. Quite a few!

Hope this helps. Dean

Dean Thanx! Would you know if head gaskets are reusable? I guess that would be a good time to try and repair the upper head crack also. I would like to assume the engine was rebuilt and clean inside the jackets because the car was half [bleeped] restored but who knows, maybe they just washed a running engine,puttied the cracks and just repainted it. Btw I used the two thin cork gasket glued together on a radius trick for the ends of the oil pan, it worked great!

I would not go any further until you have delt with the head cracked problem. Once the head is repaired you can reuse the headgasket if not damaged. However, new headgaskets are available. I have them in copper. Would have to place an eye ball on the block problem to advise you on that.

Thank you, I'll pull the head tomorrow and clean the area and do some research on how to go about repairing. I will post a pic of what looks like a crack in the block tomorrow when I tear into it.

Head is off and the crack in the head looks simple and straight forward. The block is very hard to tell whats what but looks like it is a mess with some spots looking like there is braise and others not. I dont think that the block really leaked so will leave that for now. There is at least 1/2" of crud in the bottom of water jacket. I will try and scrape,vacuum and rinse it clean and do the radiator again. Now to figure out how to weld the head.

The head crack looks like a good candidate for stitching. Check out Irontite.

You can also fix the head by cold welding it.
It's an electric weld with nickle rod and not really cold... but you never weld for long enough that you can't put your hand on the area a minute or so after you stop welding.
Once you know how to do it it's not too hard. It helps if you have a little welding experience though. And it helps to be able to preheat the entire head a bit before you start. It's a very strong repair when done right.

If you can't get it fixed I'll give you a used head (one exhaust) for the cost of shipping. Eric in Reno, NV

Dean, You were correct. With the head off I could see all the crud in there. I used a tiny firehose looking nozzle and welding wire to dig and flushed it all out the water pump hole. When I first started I could see how it was not letting much through from around the back two cylinders to the front half of the engine.

That is a very generous offer and greatly appreciated!. I have a friend who said he could fix it for me so hoping for the best.

I will keep the Irontite and cold welding processes in mind for future repairs as I do like to save what can be saved rather than toss on the scrap heap.

Yup. Crud happens.

Glad you're eliminating one more problem.

Cheers, Dean

I keep my garage warm but once I start storing freezables out there it gets annoying as you have to make 100% certain it stays above freezing so I have backup heat.

With the Evaporust, it seems to work best at warmer temperatures so I would wonder about doing some hot runs with it in the cooling system and then draining and adding fresh Evaporust since it loses strength as it gets "used up". I would think a rusty cast block would weaken the Evaporust quickly? I do like the long soak idea and I'm curious to see how it works.

Be careful of the evaporust through the radiator. It could damage the brass. You can use lye in the radiator and block for flushing rust, just don't leave it in there long. Art

Lye will take out oils and greases but not rust. Acids or chelants will dissolve rust.

So I finally got the head back. I had him leave the bead without grinding it hoping it would not leak. It still leaks so I will have him go over it one more time. It also still over heats, even after flushing out all the rust and sediment while the head was off. Very disappointing but will carry on . I will try a washer in the rad hose to see if slowing the flow will help. One positive is that i think the Stewart vacuum fuel pump is now working properly after a cleaning and new gasket

I would have the radiator professionally flushed and flow checked. With that much rust in the block it likely has plugged the radiator. I have flushed a radiator like you did and it seemed to flow OK but the engine still over heated. I replaced the radiator with a NOS one and no more over heating. Good Luck!

Slowing the flow with a restrictor is an old wives tale that won't die like not storing a battery directly on concrete lol. They've been passed around so many times that people still believe them.

As Uncle Ed has said, the rad may need a proper cleaning at an old school shop. As well a coolant filter like a Gano filter might be useful for a short while to protect the freshly cleaned rad from re-plugging with crud that has been disturbed but now stirred up with use...