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Discussion Topic:
looking for cause of overheating 34
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carguy |
07-22-2014 @ 1:41 PM
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New Member
Posts: 167
Joined: Oct 2009
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I recently took my '34 out for a little drive around town and surprised when I found it was boiling over. Not sure if it is a radiator or engine problem. Any suggestions to help determine which is the likely problem area will be appreciated.
Bill Brown '34 Cabriolet
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supereal |
07-22-2014 @ 2:02 PM
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Senior
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Joined: Oct 2009
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There are lots of possibilities. Did your car always run hot? Coolant topped off in the radiator? Belt driving the pumps properly tensioned? If these are OK, it boils down (my pun) to a partially plugged radiator, or combustion leak at one of the head gaskets. Fill the radiator to the top of the tube, start the engine, and watch for bubbles. If they appear, a head gasket is bad. If not, be sure the thermostats, if you run them, are in place and open fully when tested in a pan of water on the stove. Are any of the brakes stuck and not retracting when the pedal is released? If you pass all of these, a new radiator is the probably cure.
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carguy |
07-24-2014 @ 1:38 PM
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Thanks Supereal. I'm suspecting head gasket(s). Checking temperatures at the radiator hoses and across the radiator everything seems reasonable but at a fast idle the coolant level continues to increase even after the temperature seems stabilized with no, or only occasional, bubbling. But when I increase the rpm's I see significant bubbling when looking down into the radiator and the coolant is running out of the overflow tube quite a bit. So, Head gaskets right? Or possibly a cracked block? I'm assuming the thing to do is to pull both heads, see what there is to see and go from there? Comments appreciated.
Bill Brown '34 Cabriolet
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supereal |
07-24-2014 @ 2:32 PM
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I'd run the compression check before pulling the heads to narrow down which side is probably involved. I doubt that a cracked block is the cause if the problem just began, unless the engine was highly overheated recently. Before you reinstall the head(s), have them checked and resurfaced. Head gasket failure is mostly due to warping of the head. Look for cracks in the vicinity of the exhaust valve seats. That is the usual place to find them. I suggest that you put in a bottle of Barr's Leaks when you have the engine back together as a precaution. Let us know what you find.
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TomO |
07-25-2014 @ 7:28 AM
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I would remove the water pump belt and redo the bubble test. The bubbles could be normal. Are you using water, Prestone or Sierra. If you still have bubbles, do the compression check or drain the radiator, remove the upper hoses, fill the block with water until it is visible in the pump outlets and repeat the test to determine which side is failing.
Tom
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flathead47 |
07-25-2014 @ 8:54 AM
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Joined: Dec 2010
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May I suggest before you start taking your motor apart check your coolant for combustion products. You local garage should be able to do the test , they take a sample from your rad & add it to a test solution , it will change colour if combustion products are present. You can check your spark plugs , if you have water in the cylinder ( head gasket ) the spark plug will be white , ie steam cleaned. If you have a broken or stuck valve spring this can cause a change in motor temperature & performance , a compression test will indicate the bad cylinder. If it comes down to the radiator before you replace it try removing your thermostats & coolant if using , replace with water & 2 Cascade all in 1 dishwater tablets. Drive the car for 30 to 40 miles & drain. Replace only with water again , drive 30 to 40 miles & drain. If you have a calcium problem in your cooling system this will clean both the block & radiator. I had a boilover issue with my car read about this procedure on the Ford Barn , tried it , car now runs cool & system has been cleaned out.
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carguy |
07-25-2014 @ 10:55 AM
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Thanks everyone for your suggestions. I did run compression tests. When removing the spark plugs I found that the plug in #1 was a bit difficult to remove like there was some contamination on the threads - I didn't see anything, however. all of the plugs were black and sooty, I attribute this to not being able to drive any significant highway miles. The compression readings were from 1-8 96,90,95,94,100,96,86,95. Readings taken with throttle plates and choke open and no oiling of the cylinders. Except possibly for the 86 reading I see nothing significant here. Comments please. Thanks. Bill Brown '34 Cabriolet
This message was edited by carguy on 7-25-14 @ 10:56 AM
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CraigTerry |
07-25-2014 @ 3:35 PM
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Ok Guys - I'm dealing with a overheating issue as well. Running a 1936 flathead 8. Checked following and found all ok - thermostats, circulation in radiator, belt tension, clean 50/50 green fluid, brakes adjusted, head gasket. Runs at top of normal while underway, when i stop I'm losing fluid through the overflow. I pulled the thermostats and tested without them, got the same results. Any suggestions.
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CraigTerry |
07-25-2014 @ 7:41 PM
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Joined: Jun 2014
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Ps: putting thermostats back in, switching 50/50 mix to water with rust inhibitor. Open to any other ideas?
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len47merc |
07-26-2014 @ 4:13 AM
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Craig Terry - suggestion to review, if you haven't already, the thread entitled 'Pressurized Radiator Cap' from a couple of days ago and see if any ideas there help you. Steve
This message was edited by len47merc on 7-26-14 @ 5:01 AM
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