Overheating issue with the old slant 6

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scamp225

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Thanks i have a overheating issue with the old slant 6 its for sure overheating gauge starts to rise at idle ,I have replace the radiator cap, thermostat , water pump, radiator, ran a block tester with no change in color ran a flush kit thought system a little rust came out.
i really could use some advise
 
never starts the first time always on the 2nd idles ok shake really bad when i shut off even though i replace motor mounts
 
Have you checked the basic stuff like plugs, wires, cap and rotor, engine timing? If it runs a little rough, might be a different issue?
 
timing has been check.spark plug ect. have not been change a in while i will replace for sure.i read a lean carb can also cause overheat and i notice small leak on the jet could this cause rapidly heat but it a very small leak
 
Is it really overheating with steam and overflow? If you overfill the system it will purge the excess.
Are you checking the temperature with a thermometer or relying on your 40 year old gauge?
 
Can we get complete sentences? It sure would make it easier to read and comprehend. After all, you are asking for help. I would think you would want to be as complete and precise as possible in order to get the best help you can get. There are a lot of sharp people around here willing to help.

How about some answers?

1) How long does it take to over heat after starting from dead cold?

2) You say it over heats at idle. Does it also cool down at highway speed?

3) On the gauge, where exactly is the needle when it over heats?

4) When the light or gauge shows it is over heating, does it really feel hot? Does it run like it is over heating? Down on power? Spark knocking? Smelling coolant?

5) When it over heats, is it difficult to restart?

6) What about hoses? Have you checked the lower radiator hose to make sure it has the support spring inside and the hose is not collapsing? This is the suction side of the system and the hose must have that support, or it will suck itself shut and block the system. Although, this usually does not happen at idle, I would check it anyway.

7) Over heating at idle is usually an indication of poor air flow. Does this car have air conditioning? Is the condenser still mounted? Have you checked to see that the condenser is not clogged with road debris?

8 As stated, check the position of the fan. If it has been installed backwards at some point, it will be blowing through the radiator instead of pulling air through it.

Give us more to go on and we might can do something.
 
^^ The above are a very good set of questions and thingks to check.

Most every car is going to show some temp rise at idle after running for a while. What year/model of 225? This can be important; the shaking at shutoff may be 'dieseling' which was not uncommon for mid-70's model cars when the emissions stuff was first put oin cars; that typically gets worse with a hot engine.

BTW, installing the fan backwards won't reverse the airflow (think about the blade angle); it will still blow towards the engine. But it may place the fan in the wrong spot within the fan shroud opening and not pull air properly at idle.
 
Yes fan is on right
i put new lower radiator hose i just put the old spring back inside.there is no collapsing even when i rev the car up.
No Ac
the gauge start to rise as soon as its started go about 1/4 and then boils out through the radiator
I ran a hose through thermostat houseing and let drain from lower radiator hose .Not alot of rust came out but what looked to me liked dried gasket sealer . could this be a clogged system?
 
That's quick for it to be heating up. If you start it and let it run with the radiator cap off do you see a bunch of bubbling in the coolant?
 
O and also i have check radiator with cap off.there is no flow till it heats up but it move pretty fast after that.
another thing is after i ran the prestone stuff .my heater core leak all over inside of the cab.but still blows hot air.
if i had a air pocket or clogged block how could i get them out.
 
sorry "after i ran the prestone stuff, my heater core started leaking"
is what i mean im a bad speller sorry everyone
 
If your heater core is leaking you do not have a sealed system. Replace the heater core and radiator cap. A new cap does not always mean a good cap.
 
cuda65vpt said:
If your heater core is leaking you do not have a sealed system. Replace the heater core and radiator cap. A new cap does not always mean a good cap.
Click to expand...

2 good points.

When I got my Barracuda back on the road, both my brand new cap and brand new thermostat were bad right out of the box.
 
i know this is a dumb question but the which way does the thermostat go?
sping side in motor and other side in water outlet right
 
Today took the scamp out for a ride after bypass the heater core.with in the first mile stated overheating again. So i came right back home open up the radiator cap,it was hot to touch,and found brownish red color coolant inside.im not sure if its oil or rust.
 
scamp225 said:
Today took the scamp out for a ride after bypass the heater core.with in the first mile stated overheating again. So i came right back home open up the radiator cap,it was hot to touch,and found brownish red color coolant inside.im not sure if its oil or rust.
Click to expand...

Pictures will help us help you.
 
With the radiator as FULL as you can get it, put the cap on and squeeze the upper radiator hose. If you get sound or coolant out of the overflow hose, the cap is bad. That sounds to me like what it is.
 
please follow some of the steps above-- from the sound of your description-- your engine block /radiator has flow issues due to many years of abuse-- it needs a thorough cleaning both the block & radiator Lawrence
 
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