[Stinky123]

I've got an '06 Crown Vic w.duh 4.6...an old Poe-lease car.

The block heater used to go into the freeze plug hole above the starter. It fell out, the retaining nut came off and all of the coolant fell out too.

All was well for a few months, but now it is using antifreeze....a lot. I drove it and added a gallon. We parked it and my sonq put about 25 miles on it. I put about 10m on it and the gauge was doing funny stuff...another gallon.

There is no water to in the oil.

How likely do these motors suffer catastrophic failure when being over-heated. Any possibility that it is just a simple head gasket?

It doesn't appear to be leaking any coolant.

 

[R.S.LOGAN]

The coolant has to be going somewhere . A pressure test on cooling system should show any external leaks and a block test will tell if heads / gaskets gone . You checked for the simple things like jammed thermostat and filling and bleeding the cooling system first ? water pump o.k ?

 

[Stinky123]

I used a block testor...a tube thing that you put on the over-flow opening. There was no change in the testing fluid.

Then I pressurized the system. At 15# there was a slow drop in pressure. But, it was warm and it coulda been attributed to it cooling off.

Sooooo, I pumped it up higher, at about 17#, it started leaking. It was leaking on the passengers side. I can't tell if it is the plastic or aluminum. But, I see it between the injector and the T-stat housing....working around to the center of the motor....between the plastic and AL.

Is this common?

 

[CatSkinner]

The 4.6 has has a few problems with the intake manifold leaking.

 

[Stinky123]

There doesn't appear to be a search function to search in just one forum. I did figure out how to search in the whole engine section though.

So, I did it the old way, I scanned 15 pages of the Modular Tech Forum...nobody has had this problem.

Do I need a new intake?

 

[85ltdcrownvic]

The coolant overflow cap could be at fault too allowing excessive pressure to build but I agree its probably the intake itself leaking. I suggest trying the pressure test again and try to pinpoint the leak better. These intakes like to form hairline cracks in them so you might as well check to see if that is what it really is before buying a new intake.

 

[R.S.LOGAN]

Pressure test reading should stay steady if no leak , not drop . I've done the same increasing pressure slightly to be certain where leak is coming from .As suggested , seems like inlet manifold .

" The coolant overflow cap could be at fault too allowing excessive pressure to build " I personally have never had that on any car , usually always the opposite and cap leaking pressure , but maybe others have .

 

[85ltdcrownvic]

I have in my 00 mustang gt with the same motor and cooling system configuration years ago. No leaks and the head gaskets were fine but the cooling system would over pressurize until after running for a while it would overcome the release valve on the cap and it would spill coolant on the overflow tank. Ive seen it a few times on mustangs and crown vics actually.

 

[R.S.LOGAN]

" it would overcome the release valve on the cap and it would spill coolant on the overflow tank." Would have thought that was a sign the cap on the tank was working as it should ? Plus the poster couldn't have failed to have seen this if so but says " It doesn't appear to be leaking any coolant." .Any time I have seen the expansion tank fill up and pressurise has been caused by various other faults , sometimes as simple as an airlock and by opening cap it can clear / bleed it out .But other major faults also . On some cars the cap on the expansion tank was not even pressurised , though it is on this vehicle . But if you think it may be his fault , a few dollars for a cap should prove or not .Just my opinion on what I have found on cars in general passing through w/shop and not confined to Crown Vics or Mustangs but usually applies to most cooling systems .