Temperature Gradient

[HarryJ]

I am still wrestling with the over haeting problem on my 1921 Studebaker Light "6". I think I have narrowed it down to a clogged radiator. When first starting the car from cold and during the warm up period there is a noticeable temperature gradient between the top of the radiator and the bottom. The surface temperature is somewhat even accross the face in the horizontal direction. As it warms up, the top half will get very hot and the bottom will be very warm (ie you can't hold your hand to the surface of the top whereas you can hold it for a few seconds on the bottom). Keep in mind this is a cellular type radiator and this test is being performed with the car sitting at idle or at high idle in the shop. I am wondering if there is a scale or gummy coating on the inner surface of the tubes that is insulating to the extent that it inhibits the heat transfer capability of the unit. I have in the process of analyzing the problem run water from my garden hose both up thru the radiator and down. There is seemingly good flow. By the way I have rebuilt the water pump, cleaned out the mud in the block, and tried to compensate for the missing thermostat by partially blocking or restricting the flow thru the upper radiator hose. The temperature continues to rise at the same rate. My question is...Has anyone encountered the phenomena and am I on the right track. I am considering having the radiator recored. Is there a scale flush that will remove any scales or gums safely?

[Johan Boltendal]

The water flow in a radiator can be measured the following way;

plug the lower outlet, fill it up to the top,take out the lower plug

the radiator should empty in a few seconds with a burst of water, no

water running after the initial burst, if it's coming slow and running for a

while your chances are it's clogged.

Have it checked by a guy familiar with the honeycombs if this happens.

Good luck, Johan

[Friartuck]

Harry,

A couple of suggestions. Use a infared digital temperature gauge (pistol grip style) and measure the temps along the surface. Take the data in a X-Y grid fashion on both the outside and inside of the core. A colder temp reading should be a clogged area. Be careful how aggresively you clean the radiator, you may create more problems than you started. My first cleaning solution is TSP dissolved in warm water. If the radiator checks out even all around, check the water plate over the cylinders. My Packard six had the inner plate dissintegrate over the years where the water wasn't getting to the back cylinders. A new copper plate with holes located between the cylinders solved it. Also, you didn't mention the fan. Is it in good shape and pulling air through?

[HarryJ]

Friartuck...Thanks for the response. I don't have access to an infrared temperature guage, if they are available at a resonable price I wouldn't be adverse to acquiring one. Where can I find one? The fan seems to work fine. What is TSP, can I get it at my local parts house? There are no inner plates or baffles in the cooling system as far as I know.

[Friartuck]

Harry,

The Infared thermometer I use is the Raytek ST30 which has a straight and circular laser pinpointer. They're about $125-150 on the web. As always, if you want more capability, then the price goes up to $350. I use mine for powder coating, testing air conditioners, etc. Do get one with the laser feature.

TSP is trisodiumphosphate, a powder form cleaner dissolved in water, available in hardware stores. It's more agressive than standard cleansers. A good example is that is removes nicotine build-up on walls prior to painting.

Can you post a photo of the engine showing the water return into the cylinders?

Chris

[Guest De Soto Frank]

TSP can (or could) be found in the paint supplies section of your local home center (Lowe's, Home Desperate, etc.).

It's usually grouped with the thinners, strippers, and other preps... around here I think the brand is Savogran.

It's commonly used for washing floors, walls, and porches before repainting.

[jrbartlett]

Don't forget to check your ignition timing. I solved a long-standing heating problem by simply advancing the timing on a '35 Auburn after trying all the radiator,fan blade, thermostat and shroud possibilities.