Packard Forum Index » V-8 (1955-56)

I have a '55 Clipper with a 352 cid V-8 and I want to flush the cooling system and add new coolant. This would be the first time I have done this, so my question is:

Do I go with straight anti-freeze or a half-and-half combination of anti-freeze and water (distilled, as I have heard)?

Or is there another option of which I am unaware?

My temperature gauge (if you can call it that) rarely gets much over the C[old], so I can't say that I entirely trust it. Most of the older cars that I have owned tended to have the needle in the center of the gauge, hopefully not going much further toward hot.

As I need to take care of this matter fairly quickly, I would greatly appreciate your valuable input. Thanks all.

Anti-freeze comes in two concentrations and you have to read the label/chart on the back. One form is already diluted with water and you use it "as is". The other is a concentrate and you mix with the proportion of water that the chart indicates based on the lowest temperatures you want to protect against. Folks have used regular tap water for decades and it's OK unless your water is unusually "hard". Deionized water (chemically softened water) is preferable to distilled water though the distinction may be trivial.

DO NOT buy the extended life (generally red) anti-freeze, it's intended primarily for aluminum engines and radiators; the traditional (green or inorganic additive package) is best suited to cars with copper/brass radiators and iron blocks. I generally buy PEAK brand.

Your temperature gauge reading towards or just past "cold" seems typical of the 55/56 cars. When in doubt or curious, use a thermometer or IR temperature gun to see what the actual temperature is that corresponds to the gauge position.

O-D's advice on making your own mix of green e. glycol and water is spot on good advice. I faced the same issue with my 374 V-8 when I got it. I spent very few bucks on a new temp sender unit at NAPA and suddenly, my dash temp gauge reads just fine.

This temp sender unit screws into the back side (facing the firewall) of the left cylinder head. It's easy to get to, once you know where it is, and may have been the cheapest thing I have done to my Packard and to my driving confidence with it. On a good day, especially if you're feeling lucky, check the connectivity of the wire connecting to the sender unit; if it's loose your gauge may not read correctly. Replacing the unit when the system is drained of the old coolant makes perfect sense for good timing.

Quote:
Do you remember the specs or which Napa sender you bought?

Thank you very much guys. Your advice is exactly what I was looking for and I really appreciate it.

When flushing the radiator, flush from the bottom out through the top. Wrap a bunch of duct tape around the hose end so it fits into the radiator lower outlet. This will help to flush out debris rather than depositing them on the tops of the tubes if flushed from the top out through the bottom.

Good idea to flush the block too. If you want to go whole hog, remove the drain plugs on each bank, water pump, thermostat, and disconnect the heater. Reverse flush the engine. Removal of the pump will allow more crap to be flushed out. Also, flush the heater separately.

Good time to check the thermostat before replacing it, oh heck just put in a new 180F rated one. Good time to check radiator cap and all the hoses and clamps, including the ones to the heater. Do it once, do it right. Good luck.

(o{}o)

If you decide to replace the thermostat, get one of the type that when it fails, it fails in the open position. Conventional stats fail in the closed position and when this happens can lead to overheating and engine damage.

(o{}o)

JW, I'm not familiar with that type of thermostat, can you provide more details on how to recognize one when you see it, how it works, perhaps manufacturers and part #s?

Sure, here is a photo of the packaging of the one I installed in my 55 Clipper. They are made by Murray, marketed under the "MotoRad Fail-Safe" name, and come in standard sizes and temperature ratings. Should be available at most auto supply stores.

(o{}o)

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