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-   -   Radiator woes continue (http://www.ford-trucks.com/forums/1308273-radiator-woes-continue.html)

Wayne Waldrep 04-07-2014 10:38 PM

Radiator woes continue
 
Went to the trouble of pulling my radiator out because I thought I had a leak. All we found at the radiator shop was a slight leak in the petcock. Put a new one in and reinstalled the radiator. I filled the radiator and started the truck to burp the air out.....cap not on yet obviously. I watched like a hawk on the radiator and under the truck. Not a drip or drop at all. After about ten mins of running and letting the coolant circulate, I put the cap on. Instantly coolant started coming out of the overflow tube. This is a new 4# cap. The coolant wasn't even hot. I took the cap off...truck still running and coolant not even hot enough to blow out when removing the cap...and the overflow stopped completely. Cap back on, coolant flowing out overflow tube, cap off, stops again. I haven't even finished adding the coolant that came out of it back in yet. Never experienced this and I'm getting tired of this radiator. Any ideas because I have none on this. Thanks!

Wayne Waldrep 04-07-2014 11:05 PM

Forgot to mention that the radiator cools the truck just fine. No issues.

EffieTrucker 04-07-2014 11:34 PM

Have you looked down in the radiator to see if bubbles are coming up inside?

First I would test the cap. New doesn't always mean good.

Then I would put a pressure tester on the radiator to see how fast it's building pressure. If it's not hot but building enough pressure to blow past a 4# cap there might be more going on than just the radiator.

Normalbloke 04-08-2014 06:05 AM

Seems like the cooling system is being pressurised some how. Head gasket?
Have you had a pressure tester on to see if it holds, then increases as you start the engine?

Wayne Waldrep 04-08-2014 06:58 AM

I'll check the cap. I haven't had a pressure tester on it. And it had a few bubbles when I was burping the system.
Again, I can drive the truck for how ever long I want. It doesn't get hot. Not even in a parade for an hour going from just idling every few seconds to going 2mph for a few more.

Steve_B 04-08-2014 07:05 AM

Measure the depth of the radiator neck and compare it with the cap
I bought a new cap and it was a bit short

aussiecowboy 04-08-2014 08:25 AM

Might be time for a leak down test.

bjmayberry2 04-08-2014 08:35 AM

Quote:

Originally Posted by Steve_B (Post 14242376)
Measure the depth of the radiator neck and compare it with the cap
I bought a new cap and it was a bit short

Would have never thought of that! Great info.

53FOPAR 04-08-2014 11:44 AM

Maybe drill a small hole (1/8 inch or so) in the thermostat? Allows coolant to bypass thermostat when engine not yet hot.

harleymsn 04-08-2014 11:54 AM

Quote:

Originally Posted by 53FOPAR (Post 14243131)
Maybe drill a small hole (1/8 inch or so) in the thermostat? Allows coolant to bypass thermostat when engine not yet hot.

But his problem has nothing to do with overheating.

underthebridgejim 04-08-2014 01:58 PM

This may be stupid to ask and I sure don't mean to offend, but how full is the radiator tank, is there room for expansion?

wallster 04-08-2014 02:02 PM

If I read it correctly you're running a 4 lb cap. I would bump that up to a 7 lb cap since increasing pressure raises the boiling point of the coolant. Raising the pressure should theoretically keep the coolant from puking out due to boiling. I don't know what motor or radiator you're running though.

wally

53FOPAR 04-08-2014 04:08 PM

Quote:

Originally Posted by harleymsn (Post 14243162)
But his problem has nothing to do with overheating.


Yeah, that's why you do it. The thermostat stays closed until engine temp is reached. That means no coolant runs from block to radiator. The hole allows the coolant to pass before the engine heats up and removes the pressure. Also helps when trying to get the air out of the system.

ALBUQ F-1 04-08-2014 04:47 PM

All thermostats have some means of air bleed built in. If you hold them up to the light, you can see the seat or the disc has a wavy edge, or a notch cut in it to provide air bleed/minimum flow. The only exceptions are the kinds that have a separate disc to open/close a bypass.

petemcl 04-08-2014 05:15 PM

Sounds like lots of air in the system somewhere causing expansion and contraction. Usually in the heater core. Drop the end of the overflow tube into a gallon milk jug and the cycle the engine hot to cold 3-4 times. You should get less in the bottle each time if you are getting the air out.


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