Overheating after radiator clean out

[Pastorgmc]

Recently purchased a nice 1930 Model A. Drove a few times over past month sometimes at high speeds for short distances. Tested radiator contents only to find brown and cloudy. So I drained and put in about 3 gallons of white distilled vinegar and ran engine to clean out. Put in 50/50 antifreeze and took for a drive into town. After about twenty minutes it overheated spraying antifreeze out of the cap and below. I’m new to the Model A so am learning, but wondering about people’s thoughts on what I can do to troubleshoot. Just seems odd because it ran fairly cool with the crappy stuff in it. Has a 5 speed transmission. Capable of 50+ mph.  Thanks!

[Matt Harwood]

Did you put some kind of filter on the upper radiator hose to catch any trash that your vinegar treatment might  have dislodged? If not, you may have clogged the radiator even worse than before. Drain it again, back-flush the radiator (preferably out of the car), and see if you can get the trash out of it. After you reassemble it, put a filter in the upper radiator hose (a small women's stocking works) to catch any junk. Check it every time you drive it for the first few drives, flush it again, and repeat for a while until the filter stays clean. I also like the idea of using Evapo-Rust as coolant for a few weeks (with a filter) to really get it clean. A little more expensive than vinegar but harmless to the metals and VERY effective. 

 

Hope this helps!

[edinmass]

Do what Matt said, evapo rust full strength, drive it for a few weeks. It will probably be fine once you use it, as it takes a while for you to push water, a good sign that the evapo will probably cure you issue. It’s a shortcut, but it works 60 percent of the time without pulling everything apart. 

[auburnseeker]

The nice thing with evaporust,  is it will continue to dissolve the chunks that got dislodged. 

I can't get over the number of guys that try all the cheap methods when there is such a good product on the market that really is not that expensive. 

[cahartley]

This is the stuff I found that works.

My '29 Model A was overheating as well.

I flushed the system with clear water, almost filled it with clear water and dumped this into the system.

I drove some for about a week and then drained it.

I couldn't believe all the brown crud that came out....... 

 

https://www.napaonline.com/en/p/MCR1400

[edinmass]

Evapo rust will only attack rust, scale, and nothing else. I recommend not muddying up the advice here....first run the evapo rust for a few months, heat cycling the car as much as possible. If you still have issues pushing water, then you can run a flush through it. 

[jpage]

First, I wouldn't use antifreeze in the Model A. Anti freeze will foam and expand quite a bit and with a non pressurized system much will be forced out. I only ran water in mine and it will tend to seek it's own level, usually just below or at the bottom of the filler tube. Of course, this alone won't cure your overheating troubles. One issue, especially for new A owners is timing. Some drivers do not know to advance the spark according to speed and a retarded engine will overheat quickly. Mixture issues can also be a problem. Also running at" high speed"what ever you consider that to be, for any distance isn't necessarily good for it either. Hope you can get it sorted out.

[John_Mereness]

I do not know if this could apply, but can you be having the suction side of the water pump pulling closed the radiator hose as it does not have a spring wire in it ? 

 

Also, if you run just water, I would add a water pump lubricant - the last quarts I bought came from NAPA. 

Edited April 7, 2019 by John_Mereness (see edit history)

[oldiron]

So; when you say you like using evaporust as a coolant to really get things clean, do you mean straight "evaporust" into the cooling system ? Regards; Jerry Janson

[Matt Harwood]

8 hours ago, oldiron said:

So; when you say you like using evaporust as a coolant to really get things clean, do you mean straight "evaporust" into the cooling system ? Regards; Jerry Janson

 

Yep. I just dumped 5 gallons of it into a 1940 Cadillac that's been laid up for a while. Sometime in August we'll drain it and replace with proper coolant.