Coolant tube from Water Pump - leaking after replacement

Bammo68

TJ Enthusiast
Joined
Dec 27, 2021
Messages
160
Location
Western Australia
Hi Guys,

Just replaced the water pump, radiator and thermostat housing on my '99. I moved the coolant outlet tube (this is the hard line that goes from the water pump to the heater hoses) from the old pump onto the new one. I coated the threads with Loctite 561 on the recommendation of the local auto store. I can't do up the pipe tight though - the orientation has to be correct so that the barbed end faces the firewall and that means its a half-turn loose. The nut on the bottom the pipe is tight and there doesnt appear to be a flange to allow repositioning of the threads (you have to rotate the entire tube to install it, you cannot install it whilst the pump is on the engine).

Anyone know if that locking nut on the tube is supposed to be free to move cause it seems pretty well stuck in there...

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Update: I followed @TheBoogieman 's advice and replaced that pipe with a barbed fitting, some PTFE tape and an extension to the heater hose. Brilliant! Thanks for that suggestion. As the new thermostat housing gasket was stuffed I wound up using the Permatex Water Pump gasket maker on the thermo housing and also using a thin smear of that on the new water pump gasket. Allowed to dry and its all running perfectly, no hint of leaks and everything is running nicely.
 
I'm not sure if this was the case with yours, but I've seen several tubes leak because people will tighten, then bend bend them slightly for clearance. Due to the very thin metal, it doesn't take much to cause a small hairline crack at the tightening nut. Clever solution on the barbed fitting. That makes it much easier to remove the valve cover in the future!
 
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You should be able to tighten it slightly more. I use Teflon tape on mine. Nothing else. Some XJ guys that don't want to remove the water pump to replace the tube do this simple mod. New fitting and longer hose.
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Update: I followed @TheBoogieman 's advice and replaced that pipe with a barbed fitting, some PTFE tape and an extension to the heater hose. Brilliant! Thanks for that suggestion. As the new thermostat housing gasket was stuffed I wound up using the Permatex Water Pump gasket maker on the thermo housing and also using a thin smear of that on the new water pump gasket. Allowed to dry and its all running perfectly, no hint of leaks and everything is running nicely.

I recently sourced aluminum fittings instead of brass to avoid galvanic corrosion in my future aluminum intercooler build. In my case, the fittings wouldn't be touching aluminum, but the parts would all be touching the same engine coolant (electrolyte) which acts as the conductive path for ionic transfer.

If I had to attach brass fittings to aluminum, I'd use a healthy amount of PTFE tape to prevent the dissimilar metals from making contact.

I'm no expert, just trying to play it safe.