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1950 Overheating in traffic


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Wondering if someone can shed some light on this problem. I have a 1950 Buick Special 248. The car runs great and the temperature is always fine EXCEPT when sitting for a period in traffic or waiting in a line at a car show etc, the car overheats. Today I drove 35 miles to a show going between 55-65 mph and the temperature was fine. Parked the car at the show for a few hours and they were going to have a parade of all the old cars. I started the car up and sat in line for perhaps 15-20 min and she overheated. Once I pulled her out of the line, shut her off and let her cool down, I drove her home and she was fine all the way.

Anyone have a similar problem on a 1950 248? I'm wondering if I should start with the thermostat, water pump, or if someone else has any other ideas.

Thanks

Scott

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Idling is tough on a car, any car. But what is your idle speed set at? The 56 is set for 450-500 rpm, so that is not a lot of air being pulled by the fan through the radiator core. But does your car have a fan shroud? That would help a lotbut I don't know if straight 8's had them or not. Since the car runs right on the open road, here are some things to check for:

clogged air passages in the core. You can try rinsing the front of the radiator to clean off the bugs and debris.

Improper heat riser valve operation. Perhaps it is not opening all the way?

Improper choke valve operation, causing excessive fuel consumption and/or with todays ethanol, too lean a fuel mixture for idle.

If you do have a shroud, is it too far away from the radiator ( allowing the fan to draw air around the radiator instead of through it?)

Lastly I'd check for any possible vacuum leak.

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I have a '50 Special and mine ran cool when going down the road. However, in stop and go it would start to rise. I found a larger 5 blade that I was able to modify the spacer and installed it on my car and it helped. No one even notice's that its not factory. I walked thru and old salvage yard and finally found this one. I hear an old Cadillac with A/C has a fan that will work.

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Scott; I had the same problem with my car ,first I would Check the thermostat and if it doesnt already have one put in a 160 degree stat,if that doesnt fix it then check the timing that helped with my car, it was way off someone had clocked the flywheel wrong so I had to guess at the timing [timing marks are on the flywheel] after removing and reinstalling the fly wheel I finally got it right. then the rad. as above post above states this is most likly to fix it but now you're spending money the two previous are cheap things to address first.

Lastly, if none of these fix it you will need to remove the freeze plugs, drain plug in the block and try to clean and flush the block the best you can,crap builds up inside it and restricts coolant flow I used coat hangers and mechanics wire with pretty good results, if that does'nt work the head will need to come off and you will have to do some real cleaning.

Don

!947 56C

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Had the same problem in my 65. One time caught in traffic I had to put the car in neutral and rev the engine with the heat on full blast to get her to cool down. Radiator had good flow, or so it appeared, turns out it was 30% blocked, had it recored to a 3 row and never had a problem since.

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Thanks guys! I'm going to try the thermostat first and see how that does. The radiator (since I've only had the car a year) looks relatively clean and I don't see any debris floating in it. I'm also going to check the lower radiator hose to make sure that's not collapsing.

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I think that you can really assume it's a little plugged...especially if it's original to the car and never been serviced. That's a lot of time for crud to build up, and your standard in-car flush doesn't get it all. If it's in good shape, a boil out shouldn't be more than 50-75 dollars, and could make a world of difference. It could also bring about some real issues, like pinholes, etc. I had to have mine recored to the tune of $475, and that was 3 years ago.

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Sounds like a partially restricted radiator. You can check for restricted portions of the radiator using an infrared thermometer. Run the engine until operating temperature is obtained. Then look for sections of the core that are cooler than the rest of the core. The temperature should gradually and uniformly drop when moving from the top to bottom. Harbor Freight sells an inexpensive thermometer that is good enough for hobby use. Good luck.

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Scott, we understand your reluctance to pull the radiator. To answer your question, not really. The air side gets plugged with bugs over the years, the water side scales up. Probably the water jacket in the block is scaled up somewhat. And like Arron said, it may need to be recored. But none of this can be determined completly without pulling the rad. It is a fairly easy job to pull. Just did mine. Biggest deal is lassoing a helper to lift the hood off out of the way.

Sending you a PM

Ben

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Scott

Did the car actually overheat and boil over? Or was just the temperature gauge reading high? If the latter be advised that those early temp gauges were pegged hot at 200* F. If you have a 7# cap and some coolant/antifreeze, it should not boil over until near 230*. Check the actual temp with a known good aftermarket gauge or infrared gun. It is not uncommon for early Buicks thru the early nailheads to read hot when idling even with the cooling system in good condition....maybe that's why they started using 'idiot lights' ( out of sight out of mind ).

Willie

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Willie,

Here's what happened. As I was sitting in the parade line, I saw the temperature gauge heading into the hot zone, not totally pegged but getting up there. So I hopped out of the car and loosened the cap one turn to relieve the pressure. Got back in and people kept telling me I was leaking anti freeze which I knew was coming from the overflow tube. I then pulled over to get out of line and popped the cap the rest of the way off and was greeted with a geyser of anti freeze. After it cooled down I put a gallon of anti freeze and a gallon of water in her and she was fine all the way home.

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I have just gone through somethimg similar on my "60 Electra 401. Running was fine at 160 F however when stopped at the lights or idling, it would quickly move up to 180 then 200. Just prior to this, the water pump started leaking and the idiot light didn't work, so it boiled before I knew it. I decided to do a compression test and most were fine at around 160, but one was at 105. I pulled the heads to see what was going on and couldn't see any real blow in the head gasket, however my engineer did see what he thought was a small blow. Some of the valves were also burnt, which would not have helped the compression. I also found that some of the pressings in the head gasket were full of crud - or at least that's what I thought. What it really was was that the head gasket had rusted through in the places where the water jacket in the block meets the head gasket that shouldn't have holes in it ! Assuming my head gasket was the original one with only 60,000 miles on the car, this was probably caused by a lack of coolant in it's early life when everyone just used tap water. The head will be crack tested and given a valve grind and reinstalled. Meantime, I had noticed a small leak in the radiator and when I gave it to the repairer, he said he found plenty of crud and bent cooling fins and several other small holes. Again, the build up of crud in the radiator can also be put down to a lack of coolant in older cars when no one really knew what it was or bothered. Hopefully once all back together again, there should be no further problems, but there is a few things there that you can check.

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Willie,

Here's what happened. As I was sitting in the parade line, I saw the temperature gauge heading into the hot zone, not totally pegged but getting up there. So I hopped out of the car and loosened the cap one turn to relieve the pressure. Got back in and people kept telling me I was leaking anti freeze which I knew was coming from the overflow tube. I then pulled over to get out of line and popped the cap the rest of the way off and was greeted with a geyser of anti freeze. After it cooled down I put a gallon of anti freeze and a gallon of water in her and she was fine all the way home.

Scott

It sounds like the cooling system and cap were performing as designed. Never loosen or remove a cap from a hot engine!

1-It makes a big mess

2-It wasts good coolant

3-It can burn the___out of you and bystanders

Your engine was hot but not overheating---overheating is when it is chugging and puking out of the filler even with a good cap in place.

Adding water to an overheated engine that has puked the coolant can crack the head and/or block. Also the boiling effect loosens crud in the engine that previously was behaving itself and can now clog the radiator.

As an example: When traveling back from Ames there was Oklahoma and North Texas in my way where the temps were 100* and above. Previous trips with the stock gauge had me driving with white knuckles looking at the pegged needle and looking for signs of a boil over which never happened. This year the stock gauge was broken and with no time to fix I installed a tested aftermarket gauge. The highest temp while cruising was 190* and when stuck in traffic it was 210* with only one time it shot to 230* before I could get it into neutral and rev the engine. When parked to get gas it went to 250* and there was a little spitting from the overflow (cooled down when started).

The pressure cap increases the boiling point of water 3* for each pound of pressure---50% coolant will increase another 4*. So with a 7# cap you are looking at nearly 240* before boil over.

When the needle starts climbing and you are stuck in traffic put it in neutral and rev the engine to ~2000 rpm to increase fan speed. And if it does puke pull over, let it cool and then add water/coolant.

Willie

Dang! I was hoping someone else would answer so that I don't sound like I'm preachin' again....maybe some smilies will help: :):D:eek:

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Thanks for the advice my friend!! Not preaching at all! I always find it informative and educational to read posts from folks on here. A wealth of knowledge you can't get out of a book!!

Scott

It sounds like the cooling system and cap were performing as designed. Never loosen or remove a cap from a hot engine!

1-It makes a big mess

2-It wasts good coolant

3-It can burn the___out of you and bystanders

Your engine was hot but not overheating---overheating is when it is chugging and puking out of the filler even with a good cap in place.

Adding water to an overheated engine that has puked the coolant can crack the head and/or block. Also the boiling effect loosens crud in the engine that previously was behaving itself and can now clog the radiator.

As an example: When traveling back from Ames there was Oklahoma and North Texas in my way where the temps were 100* and above. Previous trips with the stock gauge had me driving with white knuckles looking at the pegged needle and looking for signs of a boil over which never happened. This year the stock gauge was broken and with no time to fix I installed a tested aftermarket gauge. The highest temp while cruising was 190* and when stuck in traffic it was 210* with only one time it shot to 230* before I could get it into neutral and rev the engine. When parked to get gas it went to 250* and there was a little spitting from the overflow (cooled down when started).

The pressure cap increases the boiling point of water 3* for each pound of pressure---50% coolant will increase another 4*. So with a 7# cap you are looking at nearly 240* before boil over.

When the needle starts climbing and you are stuck in traffic put it in neutral and rev the engine to ~2000 rpm to increase fan speed. And if it does puke pull over, let it cool and then add water/coolant.

Willie

Dang! I was hoping someone else would answer so that I don't sound like I'm preachin' again....maybe some smilies will help: :):D:eek:

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Yeah, by removing the cap to remove the pressure you've lowered the boiling point of the anti-freeze, causing the leak...or so it seems to me. I thought mine was running pretty warm (at the top of the normal band) one hot day after lots of freeway driving then idling), so I put my infrared thermometer on it and it was running 200 degrees. Not really hot at all. It boiled over once (plugged radiator) and it didn't puke coolant until the gauge was pegged at H. I have a 7 blade Cadillac monster limo fan on mine and even idling keeps her pretty cool. They show up on ebay pretty often...the 6 blade ones are more common...

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