Overheating issues on a rebuilt 360

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Owen Diaz

Owen Diaz

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So I’ve recently rebuilt my 360 haven’t really gotten to break it in yet due to the overheating issues I’m currently facing I even took the thermostat out so the I wouldn’t have to worry about that and still I’m overheating not really sure why thought it could be cause the radiator wasn’t bled but that wasn’t the issue the water pump is basically brand new and so is the coolant in the radiator I don’t have any leaks any help on how I could diagnose this or what I should change would very much appreciated I’ll post pictures later
 
I would check the impeller on the water pump make sure it’s not fallen off , or loose , timing too , flush the rad or replace if it doesn’t flow well does it have a shroud ? Let us know what you find ?
 
Owen Diaz said:
So I’ve recently rebuilt my 360 haven’t really gotten to break it in yet due to the overheating issues I’m currently facing I even took the thermostat out so the I wouldn’t have to worry about that and still I’m overheating not really sure why thought it could be cause the radiator wasn’t bled but that wasn’t the issue the water pump is basically brand new and so is the coolant in the radiator I don’t have any leaks any help on how I could diagnose this or what I should change would very much appreciated I’ll post pictures later
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You haven't mentioned the fan? Is it shrouded? Generally when breaking in an engine there is a heat Spike but it drops back down generally pretty quickly. I've kept a water hose handy and just ran it over the top of the radiator cool it down during the heat Spike and generally the temperature comes back down. Also verifying your temperature gauge is working properly with an external heat gun. It could be a bad radiator cap all kinds of stuff...
the picture is worth a thousand words if you give a shot of your setup and your fan and things like that it may help..
 
Owen Diaz said:
So I’ve recently rebuilt my 360 haven’t really gotten to break it in yet due to the overheating issues I’m currently facing I even took the thermostat out so the I wouldn’t have to worry about that and still I’m overheating not really sure why thought it could be cause the radiator wasn’t bled but that wasn’t the issue the water pump is basically brand new and so is the coolant in the radiator I don’t have any leaks any help on how I could diagnose this or what I should change would very much appreciated I’ll post pictures later
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j par said:
You haven't mentioned the fan? Is it shrouded? Generally when breaking in an engine there is a heat Spike but it drops back down generally pretty quickly. I've kept a water hose handy and just ran it over the top of the radiator cool it down during the heat Spike and generally the temperature comes back down. Also verifying your temperature gauge is working properly with an external heat gun. It could be a bad radiator cap all kinds of stuff...
the picture is worth a thousand words if you give a shot of your setup and your fan and things like that it may help..
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Owen Diaz said:
View attachment 1715564625
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looks good and I think I see at least one electric fan there if you have a picture of that set up a little closer that would be interesting to see as well. also having an external fan blowing like a box fan a cheap one from Walmart blowing in creating error. And as mentioned the timing? I know it's hard to shut right out of the gate but once you get it running you can kind of twist it and get the timing right. Also like mentioned stuff you can't see like a broken impeller or something...
I always break in an engine with the radiator cap off so I can see the flow...
 
I Have fans connected and on the whole time the car is on the fans is shrouded and I have a brand new radiator cap
 
Owen Diaz said:
I Have fans connected and on the whole time the car is on the fans is shrouded and I have a brand new radiator cap
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Have those fans prove them self in the past? Like keeping a previous motor well into a happy temperature range? I had dual 12-inch fans that really didn't cut the mustard very well and I ended up putting one very good 16-inch fan in and now all is well...
 
j par said:
Have those fans prove them self in the past? Like keeping a previous motor well into a happy temperature range? I had dual 12-inch fans that really didn't cut the mustard very well and I ended up putting one very good 16-inch fan in and now all is well...
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Yes the previous owner had the same set up I did and the car never ran hot on him I’m going to check it with a temp gun today to make sure the gauge is working properly but if that’s not the problem then I’m not really sure what to do next
 
Owen Diaz said:
Yes the previous owner had the same set up I did and the car never ran hot on him I’m going to check it with a temp gun today to make sure the gauge is working properly but if that’s not the problem then I’m not really sure what to do next
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Without a thermostat and the radiator open you should be seeing a good water flow. If you're getting it started for break in and running it before it gets up to crazy temperature put your timing light on it.
Are you doing a 2000 RPM cam break in?
If so you may want to let it heat up just a bit little bit and then bring it up a little higher and check your all in timing and put it at about 34 and then drop it down. I wouldn't run it up past 3 Grand but I would run it up to three grand just for a second to check your timing at three grand. Also check your timing at you're breaking speed as well.. something I kind of do by ear but just get it and kind of a sweet spot at the break in RPM..
 
j par said:
Without a thermostat and the radiator open you should be seeing a good water flow. If you're getting it started for break in and running it before it gets up to crazy temperature put your timing light on it.
Are you doing a 2000 RPM cam break in?
If so you may want to let it heat up just a bit little bit and then bring it up a little higher and check your all in timing and put it at about 34 and then drop it down. I wouldn't run it up past 3 Grand but I would run it up to three grand just for a second to check your timing at three grand. Also check your timing at you're breaking speed as well.. something I kind of do by ear but just get it and kind of a sweet spot at the break in RPM..
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I was 2000 rpm break ins and that’s when it’ll start to over heat even tho the cam that’s in the Engine was the same cam that was in before the rebuild and what do you mean by breaking speed?
 
Owen Diaz said:
I was 2000 rpm break ins and that’s when it’ll start to over heat even tho the cam that’s in the Engine was the same cam that was in before the rebuild and what do you mean by breaking speed?
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2000 RPMs is what I meant by breaking speed so the cam is already broke in? You put the same Cam and same lifters on the same lobs??
 
Most likely a timing issue. Like stated above, check your timing once you fire it up. My guess is that the timing is retarded causing the over heating condition. 65'
 
The guy I bought it off of had recently rebuilt the engine so I didn’t have to do much besides the bottom end and obviously the head gaskets
 
Plymouth 65 said:
Most likely a timing issue. Like stated above, check your timing once you fire it up. My guess is that the timing is retarded causing the over heating condition. 65'
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I’ve seen this but when you mention timing you mean On the distributor or on the crankshaft pulley?
 
Owen Diaz said:
I’ve seen this but when you mention timing you mean On the distributor or on the crankshaft pulley?
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Well you turn the timing by the distributor and check it by the crankshaft pulley...
get it started and running and up to two grand and then turn the distributor a little bit left and a little bit right and look for the highest RPM... You should hear it no problem.. then verify with your timing light on the pulley or the harmonic balancer actually..
 
you are running an aftermarket serpentine belt and it is setup to run the pump the same direction as a v belt set up, are you using a v belt pump?

What I'm trying to get at is serp belt specific water pumps typically run counter to v belt pumps.
 
Dana67Dart said:
you are running an aftermarket serpentine belt and it is setup to run the pump the same direction as a v belt set up, are you using a v belt pump?

What I'm trying to get at is serp belt specific water pumps typically run counter to v belt pumps.
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Not too sure what type of pump it is but the previous was running the same set up in his car and never had an overheating issue
 
Proving again something I tell customers all of the time, "it works great till it doesn't..."
 
j par said:
Proving again something I tell customers all of the time, "it works great till it doesn't..."
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Very true but I don’t understand how it could be the water pump considering it’s pretty new and Has barely been used even when it was on the car
 
The radiator id understand more cause it’s pretty old can definitely use an upgrade I just want be sure it needs a radiator before I go spend 400 and still have the same overheating issue
 
Owen Diaz said:
The radiator id understand more cause it’s pretty old can definitely use an upgrade I just want be sure it needs a radiator before I go spend 400 and still have the same overheating issue
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I bought my radiator for a hundred and fifty bucks from Summit and it works great for my 410 Stroker with high compression...
 
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