Main IndexAuto Repair Home Search Posts SEARCH
Who's Online WHO'S
Log in LOG

Search Auto Parts

1948 Desoto overheats in stop and go traffic

  Email This Post

kfunnyman profile image

May 30, 2010, 6:45 PM

Post #1 of 3 (2473 views)
1948 Desoto overheats in stop and go traffic Sign In

I have a 1948 Desoto. Flathead 6, 6 volt charging,etc.. It's been a while since I've posted here. In short, the car is running fine. However, it simply doesn't do well in stop and go traffic or when the weather gets hot. The hoses are good, the radiator is new. BTW, I live in So. Cal. It's hot 3/4 of the year.

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 31, 2010, 7:13 AM

Post #2 of 3 (2468 views)
Re: 1948 Desoto overheats in stop and go traffic Sign In

Basics: If only in stop and go traffic which is a strain on cooling systems with the items you listed new or thought good then it still leaves a few items to question.

Is airflow enough and as intended?

Is there a thermostat and what rating if you know? No thermostat can be a problem.

Water pump impellers could be weak, corroded.

Has there been any change that alters the speed of the fan like a larger pulley than original for it?

Check your antifreeze concentration. Most will still suggest 50/50 of EG (ethylene glycol) as the product of choice but too strong doesn't transfer heat worth a damn. It may help tons to lower concentration so it's set to zero or even 10F above with distilled water as the mix but change it every year. Pressure caps may not have been used and I wouldn't if not. Note on antifreeze containers the lie about how they also protect against boiling. In the fine print it says "with a 15lb pressure cap." That takes plain water to boiling point of 257F with no antifreeze alone! This is a huge misunderstanding with antifreeze. Way back they used to sell just "coolant" for corrosion protection and heat transfer but it wasn't for not freezing.

Note: Should know but at somewhere around the mix if EG with water set to "guess" 10F above the mix won't expand when frozen but will go to slush then to a solid as it passes lower than that. Don't try that over cold season. You still want the anti-corrosive properties and need them.

Other ideas that may help: Raise engine idle a bit. More flow of both air and coolant is achieved. Move any obstructions from grill air flow. I've seen the antiques with award plates or whatevers blocking the grille - a no no for hot weather.

Note II: Just know that once boiling the air then vapor in cooling system is 100 times worse that liquid to transfer heat adding insult to injury. Air cooling air takes tons of fins like you see on air cooled motor cycles and things.

More: When flushing system on this it should be easier to find and use plugs that should be located low on sides of block. May even use pet cocks. Debris settles low and isn't easily flushed out with routine flushing. Sometimes you can find those wont let coolant out at all! Know you are at the right ones and you would carefully poke at debris to open those up. Was annual to do that with salt water cooled automotive engines used for marine applications. Could even do that with fresh water cooled "raw" water engines but more with salt of course. At the age, even with proper products and changes used it could be part of the issue,



Aug 30, 2010, 10:50 AM

Post #3 of 3 (2405 views)
Re: 1948 Desoto overheats in stop and go traffic Sign In

also try putting in a automatic trans cooler the bigger the better a car that weighs as much as that does puts a lot of strain on the tranny and couses a lot of extra heat works great for poeple in arizono for trucks and cars also take the cooler lines out of the radiater it will help prolong the life of the trans plus help engine stay coolel also extra fan dont hert

  Email This Post

Feed Button

Search for (options) Privacy Sitemap