Coolant leak and roaring fan fixed

[captainjack]

2007 ST, 4.0, 65,000 mi., purchased used with unknown service history. I had a very small coolant leak, probably better described as weepage, appearing on the bottom right of the radiator. From every angle top and bottom I was unable to see the source or trail, just a couple of drops on the plastic block (radiator support?) visible from underneath. Inside the radiator cap everything visible was perfectly clean and the coolant looked fresh so I tried a tube of the dry powder stop leak and have not seen a drop of leakage in about 750 miles. As a point of information the owner's manual mentions that Ford coolant stop leak tablets are available so I doubt that the product will plug up the radiator or heater core unless it was horribly neglected previously.
The intermittent roaring fan continued until I noticed a few small dried spots around the radiator cap which seemed to indicate leakage or venting at the cap. The cap, its spring and seal appeared fine and there had never been any sign of overheating or high reading on the temperature gauge but I replaced the cap anyway---500 miles later the fan remains quiet.
If the leak returns I won't use more sealer and will get the system pressure tested but so far so good and I just wanted to share my experience.

 

[autobahn]

Thanks for that info! I´m seeing the same coolant loss. Not enough to replace the radiator yet, but sure enough to try some Ford "stopleak".
I flushed the system once, and got lots of old gunk out. Got me concerned, but the local dealer said that Ford put in that anti-leak after initial fillup at the plant, to reduce the risk of leakeage.
Guess they tried the easy (and cheap) way to control the 2006/07 Ex radiator problem first...

 

[Lukas2009]

Don't spent time and money for anything else than replacing the radiator.
Sooner or later you will have to replace it!

 

[Argentimage]

I just tried the barsdahl for exactly the same issue, notice a spot on the plastic, but did not see anything at all ever on the floor.

What a mess. Now I have clunking pellets in the system and the high temperature light comes on, stays there for about 30 seconds and then goes down to normal.

This started immediately after putting the pellet liquid mixture, it stopped the weep but now I have a different issue.

Every day this High temp comes on about 10 miles down the road, it can repeat every now and then if in city short run, but if on the high way it does it once, seems like something is plugged or stuck?

 

[captainjack]

Thermostat?

If your vehicle warms up and continues to overheating and then quickly goes back to normal temperature it sounds like the thermostat may be malfunctioning. If I understand correctly the thermostat should function like a valve, gradually opening as the coolant temperature around the block rises thereby permitting the coolant to flow through the radiator to remove heat. Maybe your thermostat is staying closed too long, causing overheating, and then suddenly opening and bringing in lower temperature coolant from the radiator causing the temperature to go down quickly.

 

[Argentimage]

I am 100% certain its due to dumping in the barsdahl stop leak, the issue started the very next day. And continues to look pretty skunky.

We'll tackle the thermostat tomorrow as it happens once every day. On cold start its stuck until it get to the limit then opens, once open, all is fine.