Hello there. I have a 1970 Dart with a 225 in it. My question is this: When the car is cold, how long would you recommend letting it run for before I take off? I've read on the internet you shouldn't warm up a car for more than 30 seconds, but that was specifically for "modern, fuel injected" cars. Thanks for the help

Well, on a cold morning, with everything functioning correctly, 30 seconds should be long enough to drop 'er in gear and take off, but you'll still be on fast idle and the heater won't be warmed up yet.

I don't know what the logic of not letting a late model EFI car warm up for more than 30 seconds is, unless they are specifically talking about saving fuel. Otherwise, it will sit and idle all day with no ill effects.

Hey! Your location says Southern California- I thought y'all didn't have those cold mornings out there .

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Brian (Valianator)

'65 Valiant V100 170/T-flite
'82 D150 225/4-speed
'65 Dart 225 4 door
'68 Dart 225 4-door with Valiant front clip (future project)

Only as long as necessary for that particular car to run reliably and for the fogged windows to clear, if applicable. The practice of "warming up" the car by letting it run for 5 or 10 or 20 minutes is much more harmful than helpful.

How long it takes for a car like yours to run reliably after a cold start is a factor of carburetor condition and adjustment, choke thermostat condition and adjustment, manifold heat control valve condition, distributor condition and adjustment, tappet clearance adjustment, engine oil condition and viscosity grade, automatic transmission fluid condition and type, thermostatic air cleaner system operation, as well as the condition of all the tune-up consumables (spark plugs, plug wires, air filter, PCV valve) and associated things like vacuum system integrity. When everything's in proper condition and adjustment, even on a very cold day you should be able to stomp the gas, turn the key, let the engine idle stabilize for perhaps 20 to 40 seconds, and drive off gently, allowing all the car's systems to warm up together.

Fuel-injected cars don't require nearly so much keep-on-top-of-all-the-adjustments type of tapdancing to produce reliable cold starts, but they can be achieved on a carbureted car like yours.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I agree with Dan and I will add one warning. When the engine is really cold, don't floor it and run at high RPM's until the temperature gauge has reached normal. I once destroyed a '53 Plymouth engine by doing so.

It was about -40F and my car wouldn't start. My dad gave me a push to get it running and since I was late for school, I floored it. A few miles down the road, while indicating 80, the engine began to seize. It was an expensive lesson, but one you probably won't ever face in CA.

What kind of engine was it you seized, a flat head?

When it is cold, my truck doesn' really want to run so I keep one foot on the gas and keep it idled up until I get out the yard. Once I hit the road it smooths right out.

The choke pull off can be misadjusted easily (it is set with a micrometer or vernier calipers) and a more comon problem is the choke thermostat spring gets weak with age, barely holding the choke shut when the engine is cold and needs it the most.

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82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2

Before reading this topic I warmed my ´71 Duster for 4 to 6 minutes with temperatures of 4 ºC, but after reading SSD reply I started my car, let it fast idle at 1,500 RPMS (by choke) and after 50 seconds just pushed gas pedal to release choke and it idle very well, after that I drove normally to home, no running just a quite and smooth drive to let it warm up by driving.

This Sunday evening Mexico City was at 6ºC (a cold one), so I think my engine is in good shape, and for now I will let it warm up for a minute max, thanks for the advise.

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Mopar Muscle is well defend by Slant Six!

Valiant Duster 1971

back when my 75 duster was a daily driver, for the winter it was a pretty much mandatory 10 minute warm up, if you wanted to see anything out of the window or have a smooth working tranny.

in Minnesota we have 102 degree summers and 40 below windchills (fahrenheit).

It was the daily driver for me for 3 years before I parked it, and it was my dads daily driver for eight years before that, all with a holley 390, clifford headers and manifold. I never used a block heater, or anything other than sometimes putting a small bit of cardboard in front of the rad, and I never once had any trouble starting it. I also got 26 mpg too.

for few years, I had a 78 dodge half ton, bone stock with a crappy 2 barrel (318). It didn't ever warm up.

in my daily driver now, a 95 neon, I do have the block heater now. It has much improved the cold starting (quicker turn over). I still need a good ten minutes to warm up to get all the ice off of the glass on a bad day. this car has been the daily driver for 9 years now, and I have always done it this way, and I have never had any trouble with it.

so anyway, I think it depends on the vehicle and the environment.

For what it's worth, on a cold start, I wait until my oil is warmed up before driving. I have an oil to water heat exchanger which uses engine coolant as the transfer medium. Because the coolant warms up much faster than the oil, it helps heat the oil on warm-up. I do this because where I live, I cannot 'take it easy' until it warms up. Anyway, I get less oil dilution by not driving with the engine cold. I also use an engine warmer which preheats the coolant.

Mitch