VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 80-year old honeycomb radiator

My 80-year old honeycomb radiator holds coolant quite well. It doesn't spit coolant out of the eagle rad cap or through the overflow tube until the temparature guage is near or into the red zone (this usually only happens when the engine has been turned off after a run (ex. refueling or stopping for lunch). The coolant level is near the top of the radiator core to allow for expansion. The baffle plate is in good condition.

I have reviewed previous VCCA posts dating back from 2002 to the present regarding overheating. Most of the previous posts refer to overheating of 1929-32 engines when driving the car over 40 mph or because of timing issues. I do not have that trouble. The engine doesn't overheat at 15, 40 or at 55 mph for that matter and will run all day between just above the "Alcohol Boiling Point" to the "L" mark in Normal on the temparature guage.

The timing is set for 18 degrees BTDC and the spark plugs gapped accordingly. The distributor was previously rebuilt by one of the best VCCA experts available in Eagle Point, Oregon. The engine head was magnifluxed in 2011 (with valvles in-head) and no cracks were observed.


The typical ambiant tempurature here mid-day in June/July is 85F. I am also running with great 3.50 highway gears purchased from a VCCA member in CA.

I will run the car with the hood louvres open on these days, however, it doesn't seem to matter a great deal if the louvers are opened or closed as far as the engine temperature is concerned during the run. The louvers do seem to help to expel excess heat when the car is stopped.

The engine temperature guage quickly raises into the red when stopped at an intersection waiting for a break in traffic or stopping at a gas station for refueling. The temparature guage will climb into the red zone during parade runs or while sitting idling after some time. I temporarily use a 6-volt electric fuel pump installed to help eliminate vapour lock after a short stop or when the temparature guage climbs into the red zone.


Assuming that all other mechanicals are in good running order with 3800 miles on a rebuilt motor, is the my current running condition normal or do I need to investigate the condition of the honeycomb radiator?

I would check out the condition of your radiator. After all, your radiator is 80 years old and its cooling capabilities are not what they were when the radiator was new 80 years ago.

I agree with JYD on checking the radiator. A quick check can be made by spraying the radiator with a garden hose as the vehicle is idling and hot. If the temp immediately drops your radiator needs attention. Even if it doesn't leak the old copper loses it's ability to transfer heat efficiently.

You need to be very careful putting cold water into a hot engine on a 32 as it can crack the head or worse yet the block. Refer to other post and take a look at your operators manual.
I would recommend going to a good radiator shop and they can tell you what's going on with the radiator if anything. It may be able to be hot tanked or they could rod it out. BE CAREFUL WHO DOES THIS. It is a dying art.

FYI,
Many radiator people will tell you that a honeycomb radiator can not be roded. Stay away from them. It can in fact be roded but by someone that knows what they are doing. These guys are really scarce.

Get and IR temperature monitor (several places sell a reasonably priced one) and record the temperatures across and down the radiator when hot with engine running. It should be relatively uniformly hot along the top and then decrease as you go down toward the bottom. It should be a bit cooler at the bottom middle as that is where most of the cooling air is drawn past the fins. I will be a little hotter on the left (facing radiator) as that is where the coolant exits. Hottest on the bottom right (but cooler than at the top). You should get a reasonable temperature drop (10-20 deg F depending on ambient temperature [and humidity]) from top to bottom. If you get a colder spot where it should be warmer it indicates low or no flow!

You can also use your hand but it is far less accurate than the IR temp monitor.

Hi all,

On my 1927 LM truck, I was unsure about the cooling capacity of the honeycomb radiator, so I plumbed a newer transmission cooler type of radiator in the oil line, figuring that cooler oil would help keep the engine cooler.

So far, no problems.

Cheers, Dean

I was not referring to putting cold water IN the radiator , but rather spraying cold water ON it. It's no different than driving it in the rain.

Being a glass half empty kind of guy, its possible you have some hair-line cracks in the head. I experienced this and had the same kind of symptoms you are describing. Sometimes but not always you may see small bubbles coming up in the radiator, a sure sign of one or more small cracks in the head. Jim