97' Grand Voyager overheating?

[mshelby]

I have a '97 Grand Voyager SE with the 3.0L engine, 206,000 miles. It is overheating and I'm just not sure what the cause could be. Hoping to get a bit of insight here.

First, I'll mention what I've worked on and replaced (myself) on the vehicle in the past which might be relevant....

About 4 years ago I replaced the heater core with a used one I bought in a salvage yard. If you've never done this repair it is quite a job! I also replaced the controller which is the cpu of the vehicles heating cooling system. Basically I replaced the central panel with all the heat/cool buttons on it. That panel has the computer board on the back. I've also recently replaced the thermostat, and the radiator appears to be intact with no leaks.

About 4 months ago I started hearing what sounded like water rushing through pipes which I took to be the heater core breaking down. Also at around that time or possibly a few months before, the led lights on the heat/cool panel will all flash/blink for a few minutes when you first start up the vehicle. Predictably now the heater only works intermittently. It seems to "cycle." I am assuming that it stops heating when there is no more water/coolant running through the system.

On to the overheating... I have been filling the radiator up with nearly two gallons of water each time I make a trip. The vehicle cannot go over 25 miles without needing to be refilled. When it overheats the water/coolant seems to be leaking out of one of the return hoses which run back to or from the heater core. The problem does not appear to be thermostat related. And the leak appears to be centered on the hose with the coolant relief valve on it. the relief valve is in a "T" shape which connects the hose running to the engine from the heater core. It is designed to release pressure when it overheats.

So, with all of that info, where should I look to begin diagnosing the problem. It's been a good van and I'd sure love to get 220,000 miles on it!

[Airjer_]

Originally Posted by mshelby

On to the overheating... I have been filling the radiator up with nearly two gallons of water each time I make a trip. The vehicle cannot go over 25 miles without needing to be refilled. When it overheats the water/coolant seems to be leaking out of one of the return hoses which run back to or from the heater core. The problem does not appear to be thermostat related. And the leak appears to be centered on the hose with the coolant relief valve on it. the relief valve is in a "T" shape which connects the hose running to the engine from the heater core. It is designed to release pressure when it overheats.

You need to pressure test the cooling system and find out for sure where it is leaking. The only thing that releases pressure in the cooling system is the radiator cap. When pressure exceeds the caps limits it allows coolant to flow to the overflow bottle where it is stored until it is sucked back into the radiator if needed. Nothing else on your vehicle "releases" pressure. If there is something leaking than it is broke and needs to be replaced!

I f the "T" shaped "relief valve" has a cap on it than it is a flush T that was used at one time to flush the cooling system. These are well known to leak over time. If it is than either replace the hose that it is spliced into or they make brass fittings that will splice two pieces of hose together.

[mshelby]

Originally Posted by Airjer_

You need to pressure test the cooling system and find out for sure where it is leaking. The only thing that releases pressure in the cooling system is the radiator cap. When pressure exceeds the caps limits it allows coolant to flow to the overflow bottle where it is stored until it is sucked back into the radiator if needed. Nothing else on your vehicle "releases" pressure. If there is something leaking than it is broke and needs to be replaced!

I f the "T" shaped "relief valve" has a cap on it than it is a flush T that was used at one time to flush the cooling system. These are well known to leak over time. If it is than either replace the hose that it is spliced into or they make brass fittings that will splice two pieces of hose together.

Thanks for the info. I know you are right about that. We had the system flushed once before so that "valve" makes sense. The leak is on the upper hose (to the heater core I assume) and it is leaking/steaming at the point where the "T" has been inserted/coupled. When the car is not yet running "Hot" it will still spit a jet of water out at the connector point. I'll pick up a new hose or the brass coupler you mentioned tonight. Thanks!