Did a coolant change on the 5.0, now I got a leak from the neck

[dudemancool1904]

Did a search before and didn’t find anything so apologies if this has been covered.

Did the fluids on the new to me ‘97 mountaineer. Coolant yesterday. Everything is fine except I noticed a slight smell of coolant. Popped the hood and noticed a small drip coming from the base of the radiator neck. I wiped it up and after a short drive it was back. I did take the reservoir hose off yesterday to drain it, but that’s it. Is it the cap? Do the necks on these crack? Weird that it didn’t leak at all before I did this.
Thanks

 

[C420sailor]

Blow through the hose, make sure it isn’t blocked.

I clamp my res hose, just me.

Could be a leaky cap. How old is the cap?

 

[dudemancool1904]

The cap looks old, probably original. I did notice a small tear in the gasket.
Blew through the hose, got bubbles in the reservoir.
No clamp on the overflow hose. I’ll try a new clamp and a cap and see what it does. Thanks.

 

[410Fortune]

Likely the cap gasket leaking when pressure
Builds

I put a zip tie on my overflow hose

 

[dudemancool1904]

Likely the cap gasket leaking when pressure
Builds

I put a zip tie on my overflow hose

Zip tie! Why didn’t I think of that?? Save me a trip to the parts store!

Update so I picked up a Murray/motorad replacement cap at O’reilly’s, had great reviews. Put it on cold, drove 20 miles in traffic, checked the next and had a few drops outside still. Wiped it up and went about my business, then drove the truck later that night a few more times. Each time I checked it after this the neck was completely dry. I can still smell some coolant, and the gauge does hunt a bit but my OBD2 scanner shows temps never getting over 194.

I’m gonna see if I can burp it cold this morning but I’m leaning towards air making its way out of the system.

 

[410Fortune]

It will burp itself with the overflow tank full of coolant

Hunting gauge points to reading air pockets under the sensor, common as the air works its way out.
Drive and monitor the overflow tank level for a few days no leaks call it good

 

[Turdle]

Try to get the front of truck high as you can,you want the rad cap higher than firewall heater hoses with heater running on floor vent. Let it cool down then check radiator coolant amount.

Edit.

Make sure there is no gunk in overflow. The bottle nipple will allow air in, but if clogged it'll suck the clogging stuff in which will block coolant flow back to radiator. The blow test only tests one direction of flow.

 

[dudemancool1904]

Burped it cold this morning, topped it up about a cup and went for a drive. Afterwards I checked and it’s still seeping out. I’ve isolated it to the area under the overflow nipple. I can’t tell if there’s a crack or it’s just coming out of the nipple. I’ll wipe it clean and a few seconds later I’ll get a new drip develop. Still kind of stumped.

 

[CDW6212R]

Cut a short amount of the overflow hose off, they tend to not seal after getting old and removed. Get that clamped too, or zip tied, and check the radiator cap carefully. I have had a couple of caps which would leak a hair sometimes, some are temperamental about getting them seated well. One would leak on only one orientation(the cap can go on two ways), the other way it never leaked. That was a new OEM cap, so I kept using it.

 

[dudemancool1904]

Cut a short amount of the overflow hose off, they tend to not seal after getting old and removed. Get that clamped too, or zip tied, and check the radiator cap carefully. I have had a couple of caps which would leak a hair sometimes, some are temperamental about getting them seated well. One would leak on only one orientation(the cap can go on two ways), the other way it never leaked. That was a new OEM cap, so I kept using it.

This seems to have worked *knock on wood*.

I went to buy some new hose but they didn’t have anything close to working in the length I needed. So I did like you suggested, cut the end off and put a clamp on. No drops since. I’ll still order some new hose as the one on the car is likely original but this seems to be holding. Thanks.