Radiator puking

-
B

Bobacuda

Well-Known Member
Joined
Dec 1, 2017
Messages
1,469
Reaction score
3,727
Location
Texas
Looking for ideas as to why my radiator pukes so much.
- Professionally rebuilt 318 grocery getter - about 500 miles
- new OER radiator
- new water pump
- new thermostat
- new 16 lb vented radiator cap
- new belts and hoses

Driving, you can watch the heat gauge climb in temp, then drop quickly - the cap is by-passing pressure causing the temp to drop, and creating a mess under the hood.

The coolant is red with rust, so I’m going to flush it all, replace the thermostat, use the proper mix and volume of coolant and try again. I have seen faulty thermostats before. In fact, I’m tempted just to leave it out. Where I live, we don’t drive in really cold weather that often.

Any thoughts on leaving the thermostat out?

Any other ideas what could be causing the puking and how to fix it?
 
Last edited:
Use a thermostat. Buy a quality 180° one and put it in a pan of water on your stove with a thermometer to test it before installing it. It sounds like you have air in the system or a cracked head and combustion is getting into the system. You need to pressure test the system and run it with the gauge installed to see if the pressure fluctuates.
 
Last edited:
Generally, Mopars use a 13 pound cap. I like using the lowest pressure cap I can get by with. It puts less stress on the cooling system. A lot of times this happens, the radiator has been overfilled. You're not supposed to fill the radiator slam to the top. There needs to be between 1-2" from the top of the fill neck for expansion.
 
As for the coolant level; you got two choices;
1) Put an expansion tank on it, with a recirculating cap. Your problem will be history. Mine is from a 73 Dart. It wasn't a bolt-in, but almost. Then you can fill the rad to the top. or
2) you could do what we used to do in the old days; just run it until it stops puking and the rad will have found it's own level.

As for the stat; It serves a number of functions
1) besides the obvious of bringing the coolant temp up, quickly.
2) They say, and I don't know the truth of it, that if you take the stat out, then cooler coolant will try to short-cut it's usual path of going to the back of the block, and then returning to the front thru the heads, instead it wants to go
straight from the front cylinder to the stat-house, leaving three cylinders, on each side, to get hotter and hotter.
3) They say, and I don't know the truth of it, that without the stat, steam pockets can form, which get trapped in the heads. If your temp sensor sits in one of those pockets, it will not read accurately. The sensor only reads liquid temp.
4) They say, and I don't know the truth of it, that the stat provides a working restriction, even when it is WFO, that helps to smooth the flow of coolant thru the system.

My engine cost me too much to gamble it's life away, by running it without a stat.

As for your temp-reading;
In your system, the gauge is doing something odd that's for sure. You may have to relocate it, as it seems to be in a pocket of some kind.

As for the color of the Coolant;
Dexcool is more or less light-red ..... to Orangy-red.
 
Is it doing this?

IMG_1730.gif
 
Unless you have an overflow tank and the coolant recovery style cap the radiator should be filled to approximately 1 inch down from the cap seal to allow for expansion. If you do have an overflow tank and coolant recovery cap, then fill the bottle to the full line or about half full. If you are overfilling the system, you will have coolant puke from the system.
 
I will replace the T-stat this weekend, flush the system, refill the system and hope for the best.
 
Last edited:
Im sure you know this, but if you dont.

Park on a hill or jack up front of car so the rad cap is the highest point. warm it up with cap off squeezing the upper rad hose intermittently and when she starts to bubble over put the cap on. I usually keep an eye on the coolant to see around 180* or so the coolant starts to move.

Like I said you probably already do this, Im just being thorough.


Amazon.com: HENRY DAVID THOREAU – The ...
 
I haven't run a thermostat in years. Car only gets driven in the Summer and heats up quickly just fine and runs cooler now than when it had a thermostat.
 
RustyRatRod said:
Generally, Mopars use a 13 pound cap. I like using the lowest pressure cap I can get by with. It puts less stress on the cooling system. A lot of times this happens, the radiator has been overfilled. You're not supposed to fill the radiator slam to the top. There needs to be between 1-2" from the top of the fill neck for expansion.
Click to expand...
Yes and yes.

Crusty stock radiator, 13 lb cap, no overheating and no puking @100 degree temps. Hard to see the level but it’s about 1 knuckle down if using your finger.

image.jpg


image.jpg
 
You must log in or register to reply here.
-

Back
Top