Radiator boiling over continually

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MoparMike_87

MoparMike_87

"Sh'Dynasty. That's S H comma-to-the-top Dynasty."
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So, I got my motor started on the dyno stand and the radiator was full of water. It boiled over 3 times. I was told to do this a time or two so the thermostat would kick on, however a 4th time I added an antifreeze mix and it boiled over once again. Before I continue with running the motor I want to ask, is this an indicator of something gone wrong or broken? If not, how do I get the motor to stop boiling over like this.




Thanks
 
Are you letting engine come to operating Temp. before you gun it on the Dyno? Let it warm up, refill when the T-stat open, see circulation, put on cap and let her rip!
 
What's inital timing,, crank it up to near 20*, for start up, and set it to 34ish (not knowing what you're running), after you get the bugs worked out, don't do any pulls till total timing is properly set..

,check for vacuum leaks,(lean),
 
Do you have a fan pulling air through the rad and what is the timing set at?
Do you have the thermostat installed the correct way?
:coffee2:
 
Mike!
Is this Dyno stand in your garage? You called it a stand so I kinda assume so, and it goes with the statement about " they told me".
Mike, this is not normal.
Your stand has to be set up just as it would be in a car, but even more importantly is the fan. Since it can pull air anywhere it wants to. It absolutely needs a fan shroud, and the fan needs to get up inside it. I would make sure the filler spout is the highest point in the system, install a gutted stat,and straight water. Now fire it up with the rad cap off,and immediately check for water circulation across the top of the coretubes. This will prove that the water is circulating; Or not. If you can't see the water rushing away from the top hose, the pump is not working. Go find out why. It could be that the bottom hose is plugged, or the coretubes are not passing the water down, or the pump impeller is not turning or it has lost it's fins.While you are staring down into the filler hole, look for bubbles. Bubbles could mean a blown headgasket, so if you see 'em, take a little whiff. If there is exhaust gasses coming out of there, you will be able to smell it.
To be sure, there are a couple of other reasons why the engine might spew its coolant, but get this sorted out first. Then you can chase the little things; like timing.
But Mike, If your engine is spewing in the DYNO ROOM, under load during a run, the dyno shop will have most of this bugged out already. So then you will want to show up with good headgaskets.
To that end, you will want to pressure test the system. I would test the cooling system first, to 15/20psi, and make sure it holds that, with no internal leakage. If that shows any sign of trouble. I would do a cylinder leakage test. I would try to test at 80/100psi, and watch for pressure escaping from the open rad. You can test with a 7/13psi cap, listening for it to blow off.
But above all make sure your waterpump is working.And if you can'tmake the filler spout the highest point in the system, then you will need a special recirculating reservoir, placed up high and plumbed in with a special cap on the rad.If you do not do this you will be stuck trying to burp the engine. This is not always easy.

Oh yeah, the stat will not open if its sitting in an air pocket, It needs to be sitting in liquid.

Good luck!
 
Thank you for such an inclusive list of possible errors and ways to trouble shoot and fix them. I will try them and get back to you.


AJ/FormS said:
Mike!
Is this Dyno stand in your garage? You called it a stand so I kinda assume so, and it goes with the statement about " they told me".
Mike, this is not normal.
Your stand has to be set up just as it would be in a car, but even more importantly is the fan. Since it can pull air anywhere it wants to. It absolutely needs a fan shroud, and the fan needs to get up inside it. I would make sure the filler spout is the highest point in the system, install a gutted stat,and straight water. Now fire it up with the rad cap off,and immediately check for water circulation across the top of the coretubes. This will prove that the water is circulating; Or not. If you can't see the water rushing away from the top hose, the pump is not working. Go find out why. It could be that the bottom hose is plugged, or the coretubes are not passing the water down, or the pump impeller is not turning or it has lost it's fins.While you are staring down into the filler hole, look for bubbles. Bubbles could mean a blown headgasket, so if you see 'em, take a little whiff. If there is exhaust gasses coming out of there, you will be able to smell it.
To be sure, there are a couple of other reasons why the engine might spew its coolant, but get this sorted out first. Then you can chase the little things; like timing.
But Mike, If your engine is spewing in the DYNO ROOM, under load during a run, the dyno shop will have most of this bugged out already. So then you will want to show up with good headgaskets.
To that end, you will want to pressure test the system. I would test the cooling system first, to 15/20psi, and make sure it holds that, with no internal leakage. If that shows any sign of trouble. I would do a cylinder leakage test. I would try to test at 80/100psi, and watch for pressure escaping from the open rad. You can test with a 7/13psi cap, listening for it to blow off.
But above all make sure your waterpump is working.And if you can'tmake the filler spout the highest point in the system, then you will need a special recirculating reservoir, placed up high and plumbed in with a special cap on the rad.If you do not do this you will be stuck trying to burp the engine. This is not always easy.

Good luck!
Click to expand...
 
Drilling the stat eliminates any possibility that the engine can get hot enough to puke before the air bubbles are out of the system.
They make stats like that just because of that problem, and you may have seen one before and not known it.
It is one of those things that makes you wonder why everyone doesn't do it.

It's because they don't know, listen or believe it, but it will be something you look back at and realize how simple of a solution it is to coolant puking out before the stat opens.
 
AJ/FormS said:
Mike!
Is this Dyno stand in your garage? You called it a stand so I kinda assume so, and it goes with the statement about " they told me".
Mike, this is not normal.
Your stand has to be set up just as it would be in a car, but even more importantly is the fan. Since it can pull air anywhere it wants to. It absolutely needs a fan shroud, and the fan needs to get up inside it. I would make sure the filler spout is the highest point in the system, install a gutted stat,and straight water. Now fire it up with the rad cap off,and immediately check for water circulation across the top of the coretubes. This will prove that the water is circulating; Or not. If you can't see the water rushing away from the top hose, the pump is not working. Go find out why. It could be that the bottom hose is plugged, or the coretubes are not passing the water down, or the pump impeller is not turning or it has lost it's fins.While you are staring down into the filler hole, look for bubbles. Bubbles could mean a blown headgasket, so if you see 'em, take a little whiff. If there is exhaust gasses coming out of there, you will be able to smell it.
To be sure, there are a couple of other reasons why the engine might spew its coolant, but get this sorted out first. Then you can chase the little things; like timing.
But Mike, If your engine is spewing in the DYNO ROOM, under load during a run, the dyno shop will have most of this bugged out already. So then you will want to show up with good headgaskets.
To that end, you will want to pressure test the system. I would test the cooling system first, to 15/20psi, and make sure it holds that, with no internal leakage. If that shows any sign of trouble. I would do a cylinder leakage test. I would try to test at 80/100psi, and watch for pressure escaping from the open rad. You can test with a 7/13psi cap, listening for it to blow off.
But above all make sure your waterpump is working.And if you can'tmake the filler spout the highest point in the system, then you will need a special recirculating reservoir, placed up high and plumbed in with a special cap on the rad.If you do not do this you will be stuck trying to burp the engine. This is not always easy.

Good luck!
Click to expand...

and lets not forget to test the radiator cap also. good info!
 
All you need to do to make sure a Mopar is not airlocked, is to leave the return heater hose off, and fill to that fitting, then hook it up and fill the rest of the way

While drilling a bleed hole in the stat will not hurt, you should not have to. I never even heard of drilling T stats until just a few years ago.

It is ABSOLUTELY NOT normal to have to overheat an engine to "kick in" the thermostat!!!!
 
is it boiling over or are you filling the rad to the top and it's kicking out the excess when it warms.You need 1 1/2" of air space in the tank for expansion.
The thermostat must be open or there would be no overflow.
What is the temp?
 
ir3333 said:
is it boiling over or are you filling the rad to the top and it's kicking out the excess when it warms.You need 1 1/2" of air space in the tank for expansion.
The thermostat must be open or there would be no overflow.
What is the temp?
Click to expand...

It's spewing like a geyser after about 5 minutes of being on.
 
67Dart273 said:
All you need to do to make sure a Mopar is not airlocked, is to leave the return heater hose off, and fill to that fitting, then hook it up and fill the rest of the way

While drilling a bleed hole in the stat will not hurt, you should not have to. I never even heard of drilling T stats until just a few years ago.

It is ABSOLUTELY NOT normal to have to overheat an engine to "kick in" the thermostat!!!!
Click to expand...

See, even you think it's just a trivial unnecessary thing to do and they have been making them for so long I bet Jesus had one in his car. :D

This is a Model A thermostat.
 

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if the thermostat is upside down will it eventually open after the engine is way too hot?
 
Just, my thing I do. Makes bleeding easy and works fine. I run a gutted thermostat. So the restriction of the stat is there. It's just open all the time. I learned this years ago when I installed an electric pump which you cant use a stat with. They will sell you a fancy restriction ring. No different than the thermostat minus the plunger,
 
MoparMike_87 said:
It's spewing like a geyser after about 5 minutes of being on.
Click to expand...
Spewing out of where exactly?
Dumb question: Is there a proper cap on the radiator and actually closed down? With no cap on the rad, it will spew out of the rad when you rev up the engine after the t'stat is open.
 
I have never tested to see if an upside-down stat will actually open.I mean the set -up to test it would not be the easiest. If it has the bleed-holes drilled in it, I suppose it could.Eventually...far too late eventually.
But as long as the fluid on the pellet side stays below the approximate rating, then no, the stat will stay closed. I imagine when the coolant begins to boil, the pellet on the cold side will be sitting in a mostly-air pocket, to which the pellet will not respond

I'd like to add that if the cooling system in our vintage LAs is up to snuff, it will run all day with the rad cap off. Knowing that, I run a 7psi cap, up here in southern Manitoba, even with the coolant running 205F or a little higher.. The hoses last forever. That cap has been on there since 99. I only know that it still works by the fact that it doesn't lose coolant. Well, not much anyway.
 
i have often wondered if the heat transferred through the metal housing would eventually crack or open the stat.
I do know mounted upside down it will over heat very quickly...
 
For those persons running a gutted stat;
IMO this is a bad idea, unless you live in a pretty warm climate, and/or are running EFI. The reason being, the extended warm-up period. Studies (no personal experience) have been done, that purport that a major amount of engine wear occurs, on cars with carbs, during this period. It was traced to poor fuel atomization, due to the relatively cold surfaces. The fat gasoline molecules would wash the oil off the cylinder walls and promote wear of those and the rings. It was of course,worse with the choke on.
I imagine,additionally, the gas finding its way into the oil would not do the bearings any good.

I understand that the wee little electric pumps cannot work against a stat, and for those reasons IMO,should not be on a street car.At least not in Northern climes.
 
AJ/FormS said:
For those persons running a gutted stat;
IMO this is a bad idea, unless you live in a pretty warm climate, and/or are running EFI. The reason being, the extended warm-up period. Studies (no personal experience) have been done, that purport that a major amount of engine wear occurs, on cars with carbs, during this period. It was traced to poor fuel atomization, due to the relatively cold surfaces. The fat gasoline molecules would wash the oil off the cylinder walls and promote wear of those and the rings. It was of course,worse with the choke on.
I imagine,additionally, the gas finding its way into the oil would not do the bearings any good.

I understand that the wee little electric pumps cannot work against a stat, and for those reasons IMO,should not be on a street car.At least not in Northern climes.
Click to expand...

I really don't' run my car if it's cooler than 50's or 60's outside. I don't run a choke either. I have a HP style carb with the milled airhorn. 2 pumps, start and feather for 20-30 seconds. Let it idle another 30 seconds or so and then take it easy for the first mile or 2. Take it easy as I do with any of my vehicles since they are still getting heat in to them.

The electric pumps are rated for street use. I don't run one anymore though. I just don't' see the cost/reward benefit.

My AFR is spot on and my oil doesn't get gassed out. I change it once per year. It's mobil one 0w40
 
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