replacement radiator now causing rough idle

[trozei123]

i have an idea as to what i may need to do, but i will ask the expert panel on here if my "cheat" will work.

i recently replaced my radiator as it developed a good sized hole in it. when i was at the junk yard, i accidentally broke off the barb part that the overflow connects to. thinking i could make it work without trucking all the way back to the yard two hours away, i took an old tire stem with the valve removed and cut it down to size and pounded it in. i also applied some sealant to keep it from leaking. radiator seems to be fine. but i notice when i go for a hot restart, the engine chugs a bit until i give it gas. i also notice that the temperature gauge falls back down to cold even though its full and burped of air. my suspicion is that the sealant is not holding pressure, and the chugging is caused by the ect thinking its cold when it actually is hot.

could i remove the sealant and replace it with epoxy to help the radiator hold pressure? or do i need to bite the bullet and get a new radiator? also, (and i know this has been a hot topic on here) will a 13lb radiator cap really cause air to leak into the system? i have seen many people comment that and that a 16lb is the right one to use.

 

[Roadrunner777]

While I appreciate your creativity, replacement drain valves are readily available. Dorman makes them. You just have to find a way to get the old threaded part out, perhaps a bolt extractor tool of some kind.

Here's the thing: Your method is trying to seal rubber to hard plastic in an application that temperature cycles, expanding, contracting, and pressurized. There is no dependable glue/sealant that I know of for this situation. I would pull the radiator back out, get it on a bench, get the remains of the valve out and install a new one. You may have to get creative to get the threaded core out. Extractors, maybe go at it with a dremel tool.

Here's the valve: https://www.autozone.com/cooling-he...n-radiator-drain-plug-61127/68862_976362_2606

Here is an example of extractors I might try to get the core of the valve out of the radiator: https://www.amazon.com/Irwin-Industrial-Tools-53535-Extractor/dp/B00004YOBF

The rough idle, you get the idea, the sensors are not seeing coolant consistently, so you most likely have to do more to burp the system once you get this drain valve situation sorted out.

That's what I would do, anyway.... good luck!

 

[trozei123]

its not the drain that broke. its the little "barb" on the top of the radiator under where the cap sits where the hose connects that leads to the overflow reservoir.

i figured that sealant would most likely not work. will epoxy do the job? should a 13lb cap be sufficient to hold pressure or do i need a 16lb one?

 

[974X4BLACKSPORT]

To fix the "barb" on the radiator for the overflow, see if you can find a threaded brass barb to fit the over flow hose, then clean the broken plastic around the hole for the overflow port to allow the new brass barb to thread in nice and snug, but not too tight to crack the plastic. This is a "band aid" repair, but with finesse and care, can be made to work.

 

[Gary Crist]

Take a short copper tube that will fit the hole in the neck.
Take a flaring tool and flare the tube.
Chuck tube in drill sand down flared end enough to let radiator cap fit.
Push tube in with some sealer. flare other end some. Double
hose clamp.

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