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Coolant leaking..

3K views 10 replies 5 participants last post by  Axeman82 
#1 · (Edited)
Coolant leaking.. Now head gasket GOOOONE..

I have an issue that I will try and explain as well as I can..

My EA leaks coolant. Not while driving or generally but only after the car has been turned off and about 30 mins or so has passed.

The leak is directly under the radiator. More on the side where the resovior is but still some on the passenger side.

My theory is - once the car is turned off, heat soak sets in and the pressure in the radiator builds up and forces coolant back out the resovior. The only problem with this theory is that I wouldn't think that there would be enough pressure to force the coolant level up an inch or two to the outlet hose. Also even after sitting overnight there is still gas in the resovior which also leads me to believe that there is a gasket leak between the cylinder and a water port somewhere. There is no coolant in the oil but I wouldn't imagine to get coolant in the engine as the pressue in the engine is going to far exceed the coolant system (pressure differentional).

If the radiator was cracked then it would leak constantly right? Or is the pressure build up enough to open a crack that might be there. It doesn't leak much coolant, maybe 500ml or so tops. I can't really see if any fluid comes out of the overflow but it seems to run down the chassis rail into the frame below the radiator and leak in that area.

So do you think this is a cracked head or cracked gasket? Or something else?

A few months ago I had the boucing temp gauge issue which I fixed (maybe) by drilling a thermostat, however I've never had an answer as to why the bouncing occurs. However the more I think about exhaust gases in the coolant the more I think that maybe the temp flucuations was exhaust gases passing the temp sensor, making the readings go haywire. Essentially air pockets created by gases and the temp sensor can't read gas temps.

The car is still driveable however I don't want to go a long way and discover that the car has started to leak and cook the motor. My current trip length is only about 5-10k's so I'm fine in terms of not worrying about running out of coolant. But in any case I've got coolant in the car to top it up - in a Lime cordial bottle, not such a smart thing when I think about it!!!

Thanks for any opinions..

Dan..
 
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#2 ·
Chuck some chemi weld in the car use the directions on the back and see if that stops the leak for a while. Do you notice it running a little rough on the first startup in the morning. Is there any signs of water in the oil. It will look milky the oil. Maybee the side tanks are shot and its leaking from those. Again check side tanks on radiator for coolant residue. Run your hands around things and see if you can feel water.

Im pretty sure the bouncing on temp gauge is caused by either a air pocket or the thermostat maybe a little faulty or set to a to high temp. My eb did this and once i had a hole in it it never did. Its becuase it has a constant trickle of water with the hole and stays around constant temp this way. And not just opening the thermostat when it reaches a certain temprature causing the water to mix with the cooler water and changing the temperature guage rapidly
 
G
#3 ·
Tighten your lower radiator hose.

And this is my explanation of why the bouncy temp guage occurs:

When you first start the motor the water is cold on both the radiator and motor side of the thermostat. However as the motor heats up so does the water on the motor side of the thermostat, the same side that the temp guage is on. The water on the motor side keeps heating up, and is now showing 3/5ths hot on the temp guage but the thermostat still hasn't opened... the reason for this is that the cold water on the other side of the thermostat is cooling the thermostat enough to stop it from opening. Finally at 3/4ths heat the hot water fights agaist the cold water on the other side of the thermostat, and it opens.

The thermostat opens and hot water flushes through into the radiator... pushing freezing cold water sitting on the radiator side of the thermostat into the motor. Your temp guage now takes a nose dive and the thermostat closes again because of the cold water. This time the water has to heat up a fair amount again to open the thermostat so your temp guage starts going up again(no where near as bad as the first time), finally it opens again pushing the warm water in the radiator back through the motor.

Your temp guage keeps bouncing up and down, but gets less and less each time until finally the temps between the radiator and motor side almost even each other out.


Well thats what I reackon happens anyways. Praise the lord for the thermostat hole mod tho!
 
#4 ·
It does run a little rough on cold startup.

No sign of water in oil and doesn't use oil.

I don't see why it would be the side tanks if they only leak after 30 mins after I've turned it off.

The temp gauge doesn't bounce anymore since I've drilled the hole. I know the air pocket reason but in all seriousness the air pocket should eventually release itself and I think that it is leaking exhaust gases that keeps creating air pockets.

I've been told that Chemi-weld stuff is crap and doesn't work. But obviously everyone has their own opinion.

Dan..
 
#5 ·
Before I drilled the hole the temp gauge just bounced - constantly. I could drive for 3 hours on the highway and it wouldn't stop. So for me your theory of the water temp differential isn't valid. No offence but thats just mu opinion.

The problem is more with the leaking coolant though. I'll try and tighten the lower hose but I don't see how that applies with the time delay I'm experiencing.

I'm thinking tho that all my problems are related back to the head gasket - as per my theory in the original post..

Thanks anyway..

Dan..
 
G
#6 · (Edited)
Well try and tighten it. And if I'm wrong may the fleas of a thousand camels nestle in my beard. It's either that or your radiator is busted in the bottom.

And I've had the bouncy guage, and even though it keeps bouncing it doesn't bounce as much after the first time. With a closed thermostat and water sitting in the radiator for a while cooling down significantly, then the thermostat opening again you must expect some bounce, but nothing like the first few times.
 
#7 ·
Axeman,

Quickest way is get the coolant tested for exhaust gases, you know the "sniffer" thing they put where the coolant cap goes, any exhaust gases will change the colour of the indicator thingo. That shouldn't cost too much at your friendly local garage.

At least may eliminate the head gasket.

cheers
 
#8 ·
Could also be a very small fracture in the radiator. While the radiator is hot, the coolant that leaks out evaporates. It's only once it cools down that the coolant can drip to where you can see it. May need to get an inspection mirror, and check all seams (also where the tubes join the tanks) for any signs of coolant.

The radiator shops can do a pressure test on the radiator in the car - they pump a bit more pressure into the radiator to try to find the leak. May be worth checking out!

cheers

XWish Ute
 
#9 ·
You may have two seperate problems. My old EB used to do somthing similar (intermittant leaks when switched off). Turned out to be the NEW radiator cap I put on. Put the old one back and no more problems. The problem was in the centre of the cap is a little one way valve arrangement and it failed.... hope this is the same with you
 
#10 · (Edited)
I'm pretty sure the head gasket is stuffed now guys..

Started up today and white smoke was VERY apparent on a busy street.. Overcast and rainy conditions didn't help cover the bloody embarressing sight...

It disappears after a few kays tho..

So I guess I am looking at a new gasket. The cat convertor is stuffed too but I guess it's no point replacing that until the head is fixed..

Does an EL or similar (4L) head fit onto a CFI 3.9? Cos it may just be cheaper to go and get a head from a wreckers and whack that on.. Might have to try my in-law-ishs for some cheap labour...

Dan..
 
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