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radiator hose leaking after radiator replacement
February 8, 2011 8:33 AM   Subscribe

I just replaced the radiator on my 2002 Ford Crown Victoria. I filled the coolant reservoir to the cold fill line. Now, if I let the car warm up for 10 minutes, coolant starts leaking out from under the upper radiator hose where it meets the radiator. The hose looks solid, and the hose clamp is on pretty tight so I assume the pressure is just getting really high. Also, if I open up the coolant reservoir cap, liquid coolant starts coming out, not steam. The coolant isn't even that hot. I can stop the radiator hose leak by reducing the amount of coolant in the reservoir, but the coolant level needs to be way way below the cold fill line for that. What is going on? What should I do?
posted by racecar to Travel & Transportation (12 answers total) 1 user marked this as a favorite
 
Most likely either the hose is damaged, the radiator neck is damaged, or you don't have the hose attached as well as you think you do.

Now it's possible that your radiator cap isn't working properly (these open to relieve pressure) but your hose --> radiator connection should withstand a LOT of pressure.
posted by gatsby died at 8:43 AM on February 8, 2011


Leaky/blown head gasket? Has the car really overheated recently?
posted by de void at 8:59 AM on February 8, 2011


My first guess is there's still air trapped in the system, I would try this a few times before I worry about it.
posted by mewmewmew at 9:21 AM on February 8, 2011


Yeah, sounds like trapped air. What procedure did you use when filling the system? Sometimes it can take a lot of perseverance (i.e. standing there with the cap off slowly topping it up as the engine idles) to get it all out.
posted by Rhomboid at 9:29 AM on February 8, 2011


Third trapped air. Coolant shouldn't be coming out of the reservoir at idle.
posted by Civil_Disobedient at 9:32 AM on February 8, 2011


Regardless of trapped air, coolant shouldn't be leaking from where the hose connects to the radiator. Fix this issue first.
posted by gatsby died at 9:48 AM on February 8, 2011


The proper way to fill up is to top off the radiator and don't touch the reservoir at first. Leave the radiator cap open and watch it.

Run the car till it's warm and the thermostat in the engine opens. The open themostat lets coolant circulate through the radiator in addition to the engine; when it's cold, it just circulates through the engine so it warms up faster. As the thermostat opens it starts running more coolant from the radiator.

You know the thermostat is opening when the coolant level at the radiator cap drops and the coolant starts to move. It may burp down with a big drop or two, indicating trapped air being liberated—that's good. Add more coolant as the car warms up to keep the level full up to the open radiator cap.

When it's fully warmed up and the level isn't dropping any more, you cap the radiator then fill the reservoir up to the hot fill line. As the motor cools, it will suck fluid from the reservoir into the main system and the reservoir level will drop to around the cold fill line. The point of the reservoir is to keep any air from being introduced when the motor cools, and to store the coolant forced out by expansion when it's hot.

Of course you also want to follow up on any possible leaks. Your upper hose's inside surface may be deteriorated even if the outside looks OK. Yank it off and have a look. The clamps are not optional and should be in good shape.
posted by maniabug at 9:53 AM on February 8, 2011


Most likely either the hose is damaged, the radiator neck is damaged, or you don't have the hose attached as well as you think you do.

This. Combined with an air lock in the system somewhere that will either bleed itself out as the engine warms or needs a procedure similar to the one linked to. If the coolant isn't even hot, then it is not over pressurising the system yet. Run it until it gets fully warm with the rad cap off, slowly topping up as needed, and see what happens, but fix the hose first. Perhaps the hose clip has chewed through it underneath?
posted by Brockles at 10:00 AM on February 8, 2011


I vote for a new hose and new clamps.
posted by exphysicist345 at 12:02 PM on February 8, 2011


I don't know if I'm crazy, but I don't think this radiator has a cap. I'm at work now so I can't go look but I'm pretty sure I would have noticed it. This is the model: http://www.oreillyauto.com/site/c/detail/MHT0/431393.oap?keyword=radiator&pt=01386&ppt=C0331

Maybe I should run the engine a while with the reservoir cap loose instead of the radiator cap if it's the only pressure relieving mechanism?
posted by racecar at 12:35 PM on February 8, 2011


I guess I could also pull off the upper radiator hose and pour coolant into the opening through a funnel. That would let air escape the system right?

Failing that I guess I'll go buy a hose.
posted by racecar at 12:53 PM on February 8, 2011


I don't know if I'm crazy, but I don't think this radiator has a cap.

It's possible it doesn't. With a properly designed water system there should be nothing at all wrong with filling purely from the expansion tank. It is not the 'proper' way to fill the rad separately first.

I guess I could also pull off the upper radiator hose and pour coolant into the opening through a funnel. That would let air escape the system right?

This shouldn't be necessary, nor will it guarantee an effect on the airlock. It's unlikely the airlock is between the expansion tank and the radiator, but in a hose or an internal engine cavity, so this won't make any difference.

Regardless of the air lock, your hose is either badly installed or faulty. You need one anyway if it still leaks after trying again to get it to seal. But run the engine with the expansion tank lid off until warm and closely monitor the coolant level and temp gauge.
posted by Brockles at 1:21 PM on February 8, 2011


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