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Discussion Starter #1
Any suggestions on diagnosign overheading problem in the 67 Mustang with a 289 and C4 Auto trans?

Ive replaced (and even tried with removing) the thermostat.
Ive replaced the water pump (the old one was sad)
When filling up the coolant, it took about 1.5gal, that was without taking out the engine drain plugs (this sound about right?)

Anything else to check?
Thinking:
Timing?
AF mix?
Blown Head gasget? (Please no)
:pirate::pirate::pirate:


PS: I am not an expert mechanic, just a learning enthusiest.
 

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Discussion Starter #3 (Edited)
Sitting idle, not under load, the gauge goes about 3/4 up before i get too nervous and shut it down. (Takes about 5mins to warm up from cold to this point).

Took it for less than 1mile spin around the no quicker than 35mph.. get back and its just about boiling. Touching radiator hoses just about burns fingers - and cap is too hot to touch.

Radiator - not sure of age, but its in good condition. The coolent i drained out looked pretty clean (was replaced with fresh anyway)

Doesnt cool down till the engine is shut off.

Not sure how to better explain it?
Current temp here is around 70f - so not really an environmental variable
 

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Do you have any pictures of your fan / radiator setup? Maybe some of your cooling passeges are clogged with rust scale?
 

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Yank the plugs and look for one that looks steam cleaned. That would indicate a head gasket. You could also run a compression test.
 

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Getting that hot that fast, I would think head gasket. Blowing hot exhaust gasses into the coolant. Do you notice any new gurgling noises? Does it "burp" as it is cooling down?

The other thing I don't think you mentioned was a shroud on the fan. If that was missing, it would heat up at a normal rate but then be slow to cool when the fan kicks in.
 

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I would think it would be the radiator. If it is restricted it acts like a stuck thermostat. I don't know if you have a radiator shop that can "boil it out" to clean it out and check it condition. If someone added stop leak or other product, they can stop radiator flow too.
 

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I still haven't heard any proof of overheating.

You need an actual temperature reading.
A good tune up as mentioned, is always just a good idea and a great place to start.

If there's no overflow then you are most likely NOT overheating.

You replaced the stat and pump, and believe the rad is good... How are the hoses? Does the lower hose still have a spring in it? How's the cap?
 

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I have a 67 with new radiator and water pump and it get up to 210 in about a mile. Doesn’t cool down when driving and took the thermostat out to make sure there is flow. It all flows good just gets super hot right away.
 

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First step is to verify the ACTUAL coolant temperature. Best way is to temporarily install a mechanical gauge. If, in fact, there IS overheating then there are the "usual suspects"...

Overheats after short period (5-10 minutes) with nothing slowing or stopping it. Radiator typically cool. Suspect = Improper head gasket installation blocking coolant passages.

Overheats at idle but temp moderates or goes down once moving at over 20 mph. Radiator gets hot. Suspects = Insufficient airflow through radiator core due to low idle speed, poor fan performance, etc., Insufficient spark advance at idle (use of timed spark port for vacuum advance).

Overheats going down the highway but gets better when idling or stopped. Radiator gets hot. Suspects = Poor coolant circulation at higher rpm... restriction in radiator, lower radiator hose, thermostat, steam holes, bypassed (looped) heater, insufficient spark advance at high rpm (not enough mechanical advance), severely restricted exhaust, too much valve preload.
 

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1.5 gallons of coolant is suspect. I just changed my coolant and after draining at the radiator, no plugs pulled from engine, I replaced 2 gallons. I won't discount any advice above but will suggest you consider the condition of your block and possible dirt build up in the coolant passages. There are so many other causes that were rightfully covered above, and all worth checking if you don't know your engine history.

For rust clogged engine block coolant passages, drain all your coolant and replace with Evaporust. Run the engine for a week or so. You might have a blocked radiator, the evaporust can clean some junk out of it, but you should have it rodded and cleaned. For the 289, especially if equipped with a/c, you should have a 3-row radiator, not a 2-row. Check the lower radiator hose to be sure it has the spring in it to prevent collapse when the engine is running. Pull the top radiator hose and place a nylon stocking (the type that is typically used on a women's legs and bank robberies among other uses) in the hose to catch large chunks of loose debris before they get into your radiator. To install the nylon stocking, don't cram it in the hose. Push a couple inches of it into the hose and trap it around the edges of the installed hose to t'stat housing.

After a period of time, drain and flush the Evaporust. You'll be amazed at what comes out. You may also be amazed by the failure of metal parts that now leak and were sealed by rust or were about to fail. Don't worry about getting every last drop out of the car, it becomes inert and won't harm anything. It doesn't affect gaskets or bushings. Don't forget to keep your heater on when flushing.
 

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Note that there are two threads here, one of which is from 2012. New thread starts at post #9.

I will go with the first simple thing I see: Is your fan coming on?
 

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Get yourself a combustion leak tester, rent it from your local parts store. It'll show you whether you have a blown head gasket with pretty good accuracy.
 

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On a more or less stock 289 210* within the operating window. A temp of 230* I would consider super hot though in the hobby stock and even the shifters that’s where we ran the race engines.

Cooling is one of the most misunderstood facets of automotive engineering. Bart’s post should be made into a locked sticky where known symptoms, causes and fixes are available. The is so much myth and folklore out there that if someone is not familiar with how a cooling system is engineered it’s easy to not be fully informed.
 

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I agree with the above. I fought a cooking issues and tried everything @Woodchuck said and more. For sure get an actual temperature gauge to get an accurate reading of the engine temperature. Start with basic things, and don't listen to posts that suggest a lower temp thermostat as a solution. Do a good flush with I suggest citric acid or thermocure. Be aware that thermocure may take a couple of flushes and is hard to flush completely out but it probably does the best job. I finally figured out that it was a warped head in my case that was letting hot exhaust gases in my coolant system. Try one thing at a time. And be methodical and you will figure it out.
 

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Have you burped the system? Many times the above symptoms have been resolved by making sure all of the air is out of the system, no air pockets.
 

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Fruish, we need more information. Did you replace the radiator and water pump because it was already overheating or is it a new build? Then look at all the other posts and answer those.
 

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In your picture it looks like you've had some spilling near the top of the radiator. What size of cap do you have? Is it leaking? I'd test it and make sure it's not the radiator cap that's giving you the problem. I believe most auto parts stores can test them for you if you can't do it yourself, or for probably $10-15 max you could buy a new one with a higher rating and test it that way? Also, where are you getting the 210 degree figure? From a gauge? I've got a laser thermometer that I like to use. It's pretty accurate and trust it over the gauges that are sometimes decades old and not as reliable.

 
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