Stop Leak?

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
......... Also I would not leave that radiator cap loose that lack of pressure me be why you're Head gasket failed. that weeping radiator may have been going on for a while. Without that pressurizing the system the coolant will boil in the hot part of the engine creating pressure where it shouldn't be.

This may be bob, however I left the cap unscrewed for about 3 years BECAUSE I had a head gasket leaking exhaust gas into the cooling system. Now whether the unpressurized system hastened the final failure of the head gasket, I don't know. My theory, then, for doing it was to keep pressurized coolant from being driven back thru the breach in the gasket that was leaking the exhaust.

Also interesting is the opinion of the shop that did the head gaskets. They said that by leaving the radiator cap unscrewed, it could keep the engine control computer from running in the 'closed loop' status, thereby making the engine run too rich and affecting the mileage, amongst other things.

At this point, I will take your advice and screw it back down and work toward changing out the radiator. In the mean time I think the ebay link that dannys2004glastron posted shows the release clips that I need. However, I think that NAPA has the same thing for around $7.00.

My original intent was to find out, assuming I needed the tool, how the fittings actually worked.
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
They are pretty simple fittings, you slip the right sized tool over the tube and slide down the tube until it engages the clip, then pull apart, pretty simple. Based on the tool kit I have, it states, use the 5/16 in tool to release the connectors on the transmission lines and Ford radiator lines. dannys link shows a Canadian auction at $15.95 with a $15.95 shipping rate, so that is pretty spendy.
 
Last edited:

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
They said that by leaving the radiator cap unscrewed, it could keep the engine control computer from running in the 'closed loop' status, thereby making the engine run too rich and affecting the mileage, amongst other things.
Not likely. The only thing that you were doing is possibly allowing the coolant to boil at a lower temp than normal. The ECU is measuring temperature and as long as the temp stayed below the boiling temp of unpressurized coolant(217 or so), the ECU wouldn't know anything.

You would think that an auto shop would know better than this. Amazing!
 
Last edited:

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Not likely. The only thing that you were doing is possibly allowing the coolant to boil at a lower temp than normal. The ECU is measuring temperature and as long as the temp stayed below the boiling temp of unpressurized coolant(217 or so), the ECU wouldn't know anything.

You would think that an auto shop would know better than this. Amazing!

Well Bruce, I would intend to agree with you. Over the three years I left the radiator cap loose, the temperature never varied on the gauge. But then I am not the engine scientist.
 

bobsquatch

Petty Officer 2nd Class
Joined
May 20, 2013
Messages
154
MT. You mean like the fuel lines on Ford now with the O-ring type push lock connectors?

Hey Boomyal, I don't doubt that you could get away with it under light driving conditions indefinitely however if you were loaded it would reveal it self quickly if you're coolant was boiling below 250. Regular driving with brief periods of heavy acceleration to get on the freeway and such would probably go unpunished. However heavy loading in hot weather picture pulling a 10,000 pound trailer up a 6% grade for 20 miles in the summertime would probably reveal itself to you in the first trip.
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
MT. You mean like the fuel lines on Ford now with the O-ring type push lock connectors?

Yup, I have 4 different Fords, that have push lock connections on the tranny cooling lines, quite a few of the newer cars use the push lock connections these days. That is why they now sell kits with various sized tools in them, so you don't have to purchase them one at a time any longer.
 

bigdee

Commander
Joined
Jul 27, 2006
Messages
2,665
They said that by leaving the radiator cap unscrewed, it could keep the engine control computer from running in the 'closed loop' status, thereby making the engine run too rich and affecting the mileage, amongst other things.

This is an accurate statement. I had a relative whose Ford would not shift into OD. The Ford dealer replaced the transmission under warranty and the problem still existed. An independent shop found the radiator cap to be deffective. The shop replaced the cap and charged him $50 and the transmission has shifted fine ever since! Sounds crazy but shop said temp was below threshold to allow OD.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
The cap doesn't do anything to raise the temperature that the coolant gets to. Only thing it does is raise the boiling temp.

I can drive my Silverado around all day at it will never get above 190. Trust me, if I remove the cap, the temp will stay at 190. If I take the thermostat out, that would be another story. Maybe that is what your relative did and is confused.
 
Last edited:

bigdee

Commander
Joined
Jul 27, 2006
Messages
2,665
The cap doesn't do anything to raise the temperature that the coolant gets to. Only thing it does is raise the boiling temp.

I can drive my Silverado around all day at it will never get above 190. Trust me, if I remove the cap, the temp will stay at 190. If I take the thermostat out, that would be another story. Maybe that is what your relative did and is confused.

I talked to this mechanic and his theory was the van had low coolant in the block because the cap was leaking and not allowing coolant which normally flows into expansion tank to return back into radiator. The low coolant level was not being sensed by the temperature sensor which is the highest point on the engine. This prevented the car from going into closed loop. After car ran for an extended time steam would reach sensor and trigger an overheat condition which put the engine in limp mode which also inhibited OD.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
That is possible but that would happen even if the cap was good and there was a leak somewhere else. Need to train your relative to check fluid levels occasionally.

So it was an overheat condition due to low coolant level and not a temp low threshold like you originally said?
 
Last edited:

bigdee

Commander
Joined
Jul 27, 2006
Messages
2,665
Need to train your relative to check fluid levels occasionally.

So it was an overheat condition due to low coolant level and not a temp low threshold like you originally said?

BOTH, re-read my post.
Give him a break he is 84.
Fluid level was ok on expansion tank...that is proper way to check it.
Ford dealership missed this too.
 
Last edited:
Top