Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Help w/ coolant not getting sucked in by radiator

Hi, I have an '01 Dodge Ram 2500 5.9L V8 with 150,000 miles. I have a problem where the coolant isn’t sucked into the radiator from the coolant reservoir. I can remember when I only had to fill the reservoir. This truck was involved in a front end accident in '05. The radiator was one of the parts replaced. I can tell you that when you open the drain plug from the radiator, nothing flows out. At the end of '08, the original water pump was replaced. About a year ago my hot temperature light turned on. I made it home since I was only about a mile away. When I opened the hood the coolant reservoir was full, so I waited a couple of hours for the engine to cool. When I opened the radiator cap I noticed there wasn’t any coolant inside the radiator! I get some coolant and fill it to the top (it was a large amount).So I replaced the radiator cap and have found that I still have to fill the radiator every 3 weeks or so and the reservoir continues to be full and now I just fill the radiator with water because I don’t want to keep spending money on coolant. I do notice an odd light gushing noise near the glove box every time I turn on the vehicle in the morning (I’ve heard this noise for about 5 years now). I can also hear it when at a stop and begin to accelerate (not all the time though). It was serviced 2 weeks ago and the radiator cap was again replaced, top and bottom hoses replaced, thermostat replaced and was told a flush was performed. So I take it back the next day and tell them I still hear the odd gushing noise. Before I took it to back to them in the morning, I opened the radiator cap and could not see any fluid in the radiator. When I picked up the truck at the repair shop the day before, I saw the employee fill the reservoir and the radiator. He then turned on the truck and topped it off with coolant as the coolant level in the radiator dropped. I am worried that work and money was spent without fixing the problem.

Could the problem be the radiator itself, since nothing flows out when the drain plug is opened, could a clog cause this? Should I be worried about the noise I hear inside the cabin in front of the glove box (the employee at the shop claimed he heard nothing, I guess he didn’t even try to listen to it)?

Please help, I need to make a long distance trip soon and don’t need trouble on the way!

Your heater core (cabin heat) is probably behind the glove box, but a flushing sound is unusual. I wonder if you have either air or debris in the system, possibly stop leak. I just changed out the radiator in my minivan and had overheating and noise problems from air in the system. A poster told me to remove (from the radiator) and fill my upper radiator hose, replace it, then top off the radiator, or if my thermostat was at the top of the system to detach a heater hose (generally about 1" diameter near glove box) and fill the radiator until fluid came out of the hose. Check out “burp or bleed a minivan” and you’ll find the suggestion and the name of the poster. Hope this helps.

The fact that you accurately described the problem (“coolant gets sucked in buy radiator”) means that you understand how it is supposed to work, so you know what the problem is. If no vacuum is being formed as the radiator cools, that means that it is able to suck in air somewhere. The fact that you have to keep adding water corroborates that there is a leak somewhere. You just have to find the leak.

If you don’t see any wet spots anywhere, I would first suspect the radiator cap.

Fill it with water, drive the vehicle until it is warm (pressurized), and crawl under the front end looking for dampness and/or drips. If the problem is not immediately apparent, try a new radiator cap. Also inspect the hose from the reservoir to the radiator for cracks or loose fittings. The leak could be from the radiator or the engine.

The noise near the glove box is most likely vacuum leaking from an accumulator or actuator on the cabin ventilation system. I suppose it could be your water leak if the water is finding its way to a drain rather than to your carpet. You probably would have smelled hot antifreeze in the cab if you had a leak under the dash.

You are hearing water gurgleing from behind the dash because you cooling system has air in it because of a leak. Your coolant recovery system isn’t working either because of a leak in the tube or the recovery tank or air is getting in the radiator because of a leak’ Get your radiator filled and pressure tested hot to find out where you are losing coolant.

A blown head gasket is a possibility… The “air” in the radiator could be combustion gasses…This will blow the coolant out of the radiator and into the overflow tank and it won’t be drawn back in…

There is a dime sized button on the center of the radiator cap snout. That button should be free to be easily pulled down. That button opens(should) when the engine cools and pressure drops.

I bought a replacement radiator once, aluminum core with plastic ends. Turned out the hole for the tube that goes to the overflow was never drilled out.

I would suggest checking for an obstruction either in the hose or in that tube. Could be a simple fix.

Also check the hose that goes from the overflow tank cap to the bottom of that tank. It can be gunked up at the bottom. Also check the vent tube of the overflow tank.

I had the problem of coolant not being sucked back into the radiator on a 1993 Oldsmobile 88 that I once owned. The problem was the hose between the radiator and the reservoir. The hose would allow the coolant from the radiator to flow into the reservoir, but would collapse when the radiator would try to suck it back in as the car cooled. THe repair was simple and inexpensive–$2 for a piece of new hose and 10 minutes to install.