You may notice that coolant has collected on the ground under your car or that your reservoir tank is not as high as it should be. It's been done by many as a quick way to cool off an overheating cooling system. If the coolant reservoir cracks or breaks due to old age or overheating it will leak. Feel the hood to confirm if the car has cooled. If your cap isn't venting, this causes excess pressure in the cooling system, and can cause leaks or a collapsed radiator hose. Over the weekend, I popped my hood off the LX570 (2009, 106k miles). Add coolant to the reservoir as well. Comment; Flag; More. This stage bleeds air from the engine, rad and fill tank. Meanwhile, the coolant expands and creates additional pressure in the radiator. Blew into reservoir and again capping off over full tube. If the temp is rising past normal, check the radiator fan to see if its running. Keeping your engine coolant reservoir at manufacturer recommended levels is critical to your car’s operation. Add a mixture of water and antifreeze to the reservoir until the coolant … I went to Autozone, got a $10 radiator cap, put it on, and the problem stopped. 12 people found this helpful. My Insight also doesn’t have a vent or overflow for its non-pressurized reservoir. A bad one won't hold pressure or won't suck coolant out of the reservoir when the car cools off. Keeping your engine coolant reservoir at manufacturer recommended levels is critical to your car’s operation. Need a cap. Coolant cap cant get coolant reservoir cap off. may have a blockage in line going to recovery tank. 196000 And fine. You might have 2 electric fans, one for the engine coolant and one just for the A/C system, so check them both if you have 2. Yesterday while in idle waiting for a light my coolant reservoir popped! Buying & Selling. Page 1. Kind of lost on what could be causing this problem some people have pointed me in the direction of a blown head gasket but there's not coolant in the oil so I'm not sure. Some cars have a pressurized coolant system, like my 1986 Porsche 944 . And the the cooling fan mod is not an "always on" mod. I could be possible to have a cap tight without no leaks, but having its valve damaged, which would lead to overheating as well, since the cap won't be managing system pressure as it should, probably sending coolant to the system's expansion tank. Leaving off the cap will prevent pressure from building up. I replaced my radiator, hoses, and since my heater core is mostly clogged I bypassed it. This could be evidence of a slow leak in your system. I bought another heater core, but I am just waiting for it to come in. 119.8 KB Views: 985. image_1487816096358.jpg. It doesn't happen all the time. Some cars you have to bleed the air out of the system when coolant gets too low and after you top off the coolant too. So, the radiator coolant overflow tank functions to serve this exact purpose. A cap that is no longer sealing could also cause a leak. In normal circumstances, the coolant gets ousted out from the reservoir overflow tube, the moment the engine starts warming up. To enable Verizon Media and our partners to process your personal data select 'I agree', or select 'Manage settings' for more information and to manage your choices. Add to cart. IF the upper radiator hose is also swollen when the engine is hot you could have a bad radiator cap not allowing the system to vent. Any time there is a coolant leak, there is a possibility of the engine overheating. This is not the first car I've seen this happen to, my Jag also suffers from the same problem, but takes a lot longer to manifest itself. We use cookies to give you the best possible experience on our website. I drove another 30 minutes and the same thing happened. Most newer car models have labeled radiator caps. No farther issues after topping off my coolant reservoir to the correct level. All is well! My Car Coolant Overflow Tank Cap Pops Off. When the pressure is too high, the cap vents excess coolant to the coolant reservoir. supposed to hold 16 lbs pressure to keep the coolant from boiling too easily. Coolant came out around radiator cap. 1. Any such Leaks is an Indication of a problem. A malfunctioning radiator cap seal can allow air to enter the system, often producing bubbles in the expansion reservoir. 1 - 75 of 135 results Dorman 54201 Dorman Help! Dorman 82599 Coolant Reservoir Cap For Select Infiniti / Nissan Models. You may even be able to smell the coolant leaking. Alternatively, you can check your owner’s manual for its exact location. Why does my coolant reservoir cap keeps popping off? The A/C is on, and the reservoir cap be able to smell the boils. And inspection time and exposure to temperature changes, that plastic can weaken, and since my heater core mostly! Possibility of the radiator cap controls the pressure inside your cooling system viton now... 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