How Long Does It Take For your Car to Overheat

[harryc]

I have been working on my car while it is running and today I noticed it will start boiling after 10 minutes. ( from a cold start) I have tried this several times and at exactly 10 minutes it cuts loose. This is in cool weather with spark retarded. I have never really checked this before today. It seems to run cool on the street as far as I know. (I have no motometer or temp gauge). I suspect my radiator is clogged--------any thoughts?

[1931 flamingo]

It shouldn't overheat. JMO
Paul in CT

[Bill G]

It will run hotter with retarded spark. I have idled mine for a half hour and no over heating. I do advance the spark to about 1/3 down after it starts.

To answer the question, mine has never overheated from idling, but I have only owned the car for about 9 months.

[Patrick L.]

if the spark is fully retarded it probably will/should overheat. After starting the lever should be set at about 8:30 to 9:00.

[WHN]

If it is running OK on the road, I would say the retarted spark could be the problem.

I have never had a Model A overheat. We run regular water, and engine side pans. I also don’t leave a car idling for any length of time.

I would check your timing, and run a radiator cleaner just to make sure. Enjoy.

[40 Deluxe]

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Originally Posted by harryc

I have been working on my car while it is running and today I noticed it will start boiling after 10 minutes. ( from a cold start) I have tried this several times and at exactly 10 minutes it cuts loose. This is in cool weather with spark retarded. I have never really checked this before today. It seems to run cool on the street as far as I know. (I have no motometer or temp gauge). I suspect my radiator is clogged--------any thoughts?

Clue #1. "with spark retarded." Advance the spark! When the spark plug fires late, fuel is still burning when the exhaust valve opens, which overheats the exhaust valves, ports and exhaust manifold. There should only be spent exhaust gasses flowing out into the exhaust, not a live flame. See what happens when you pull the spark lever about 1/3 down, as suggested. Since there is no automatic spark advance, it is up to the driver to adjust the timing for varying speed, load and throttle opening. The spark lever is not a "set and forget" control. It needs to be continually readjusted as you drive.
Of course, if this doesn't fix it further diagnosis is needed.

[harryc]

I never drive with the spark retarded. I am only curious if other peoples cars overheat given those driveway circumstances. 10 minutes seems to quick to me given no load and cool weather even if spark is retarded

[Ernie Vitucci]

Good afternoon...The spark lever should only be in the up position to start the engine. Then move it down about 80% of the way and see if stays cooler. Also check your points and plugs for the correct gaps...Ernie

[Bill G]

Originally Posted by harryc

I never drive with the spark retarded. I am only curious if other peoples cars overheat given those driveway circumstances. 10 minutes seems to quick to me given no load and cool weather even if spark is retarded

You shouldn't idle with it retarded either.

[Fred K-OR]

Do what is recommended above but it sounds like you have more of a problem than that.

[Jacksonlll]

Your radiator is plugged like most are. Try going 45mph for 10 minutes straight and if it does not boil over, you are good. My guess is, it won't make it.

[harryc]

thanks for the suggestions

[Mikeinnj]

Harry, Before you go crazy and mess with your radiator or other things, do as suggested with the timing lever and advance it (down) right after you start up the engine. I have seen exhaust manifolds glowing cherry red hot when idiling or driving with spark lever fully retarded. The exhaust manifold can become permanently warped from over heating.
Try it and let us know the result.

[cpf240]

I'd start with adjusting the spark lever first before getting any deeper. Easy to do, and the results should take only 10 minutes...

[1930marie]

Originally Posted by Patrick L.

if the spark is fully retarded it probably will/should overheat. After starting the lever should be set at about 8:30 to 9:00.

X2

Try advancing your spark half way down the quadrant when she fires and you can tweak it from there. If the boiling doesnt stop, give these a checkout.

Radiator at max efficientcy (recent article in Restorer)
Correct Timing
at idle spark set as Patrick states

I think the longest I have ever left my car at idle (spark at 9:00 oclock) was about 30 minutes while talking to a fellow car buddy about my new engine. There was no heat build up nor was the motor even bordering on being hot. Im just for once lucky I guess.

[Kurt in NJ]

I can idle drive in a parade for as long as needed with the spark lever at any setting ---this is 1st gear at walking speed, not riding the clutch, slow parades are at near full retarded, I use spark advance for speed in parades

A mouse nest in the muffler will cause overheating, eventually it catches fire and gets blown out usually

if water has been used for coolant rust will fill passages and cause hot spots, clog radiator

[SteveB31]

It should never overheat.

[hardtimes]

Originally Posted by harryc

thanks for the suggestions

Hey harry,
Is this the roadster ?
Do you use anti-freeze to prevent rust, or some such ?
These blocks had a penchant for rust piling up towards the last cylinder area. If no rust preventative used, that rust could also end up messing with radiator flow also.




I've got just the opposite 'problem', in that, I installed a 160 thermostat/anti-freeze and wwith nos Russian block with re-cored radiator. Seemed to run cold. I put a steward warner temp guage in to double check. It is a cold blooded machine ! Guess 180 thermostat is next install ?

[WHN]

The way a Model A cooling system was designed, when the block reached about 180 degrees the cooling system starts really working. Natural flow of hot water, up and out, along with the pump.

Designed engine operating temperature I believe is 160 to 170 degrees. Again, once you get the water flowing.

So the water gets to about 180 degrees, starts the natural flow of hot water up and out, cooler water down and in. Than along with the pump and fan engine levels off at around 165 degrees. This is assuming everything is in good operating condition. Radiator, block passages, pump, fan, hoses, timing, whatever.

With the oil system used, you don’t want the cylinder walls to get hot enough to effect oil flash.

Below 160 degrees, I think your engine would not be operating properly, especially with today’s gas.

[Manager]

GAV set too lean can also make them run hot.

[AL in NY]

With a GOOD cooling system.........................NEVER

[F.M.]

In about 25 Miles after a re-build at a Restoration Shop in Tenn..

[burner31]

Thermocure by Evapo-Rust Cooling System Rust Remover and Flush - $20
Prestone Radiator Flush & Cleaner - 22 fl oz bottle - $4
Both at Walmart, Evapo-Rust work very, very good, top of the line stuff, the Prestone works very good also for the price.
Run it in the car for several days depending on how many miles you drive.
And my car does not overheat, in fact she runs almost to cool.

[Dave in MN]

Originally Posted by SteveB31

It should never overheat.

I basically agree with Steve on his comment.
At idle with the spark fully retarded, it should not overheat.
If you were to drive the car with the spark fully retarded, you should expect it to overheat.

Check your timing, carb settings and your radiator. I agree with you...your radiator is not up to needed capacity.
Good Day!

[daren007]

I have never had a problem.

[Growley bear]

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The reason the engine overheats with retarded spark is that the ignition occurs too late in the cycle and the combustion cycle has not finished. The mechanical cycle has finished and the BURN is still in progress when the exhaust valve opens. This blue/white HOT fire will heat things up rapidly as it occurs outside of the cooling system.

[George Miller]

Originally Posted by Dave in MN

I basically agree with Steve on his comment.
At idle with the spark fully retarded, it should not overheat.
If you were to drive the car with the spark fully retarded, you should expect it to overheat.

Check your timing, carb settings and your radiator. I agree with you...your radiator is not up to needed capacity.
Good Day!

plus 1

[SuperDave]

A few years ago I bought an IR temperature measurement gauge from Harbour Freight. Just aim the laser at an item and it tells you the temp. Comes in handy to measure temp of water doing into the radiator and what is coming out.
I also watch tire temps on my hauler trailer. An abnormally high temp gives me a hint that i need more pressure.

[ChicagoBob]

It's been about 20 years, and mine hasn't overheated yet.