Reduce Coolant Loss

[Bob Bidonde]

Ride behind a Model A that has had its coolant topped-off and you will see a significant stream of coolant flow out of the radiator's overflow. Here's a way to minimize coolant loss, but retain the overflow function.

I tested this idea on my Coupe for several thousand miles of fast driving on the interstates, and it works well. The photo shows the simple orifice that's in my 190A. The orifice is made from a stainless steel 1/4-20 x 3/4" long hex head bolt. Drill a 1/8" diameter through the bolt, deburr both ends of the hole, and slip the bolt into the overflow tube. A 1/4-20 bolt ideally fit the reproduction radiators in my 45B Coupe and 190A Victoria. Check the inside diameter of your radiator before buying a bolt.

Also carefully and slowly bend the brass overflow tube to get its opening as high as possible without interfering with the radiator cap. Insert a snug-fitting drift pin into the tube to make the bend.

Just one more comment before I leave the podium. The coolant in my 45B is a mixture of tap water and Barr's Stop Leak, the Barr's in the jar with liquid and pellets. This coolant brew is used year-round without anti-freeze, and there haven't been any issues. It looks nasty, but it doesn't freeze, it doesn't cause boiling and there is no coolant leakage or seeping. For those who think the Barr's will clog the orifice and or radiator, it hasn't happened to my Model "A" in the years I have been doing this.

[Redbird]

I have seen this talked about on the forum w/o the hole, but what does it really accomplish? I know you increase the coolant capacity by a couple of cupfulls. Has anyone really tested your findings?

[Kurt in NJ]

What happens if you have a overheating event that makes steam --in excess of the flow of the orfice

[Bob Bidonde]

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I had one overheat with the orifice in place, and no damage resulted to the radiator or anything else in the system. The overheat was the result of an ignition problem that caused a change in the ignition timing. I tested the orifice for several thousand miles of highway driving (55 to 65 mph) without issue. It works for me.