Hello All, I need help in determining why I all of a sudden have an anti-freeze over-flow issue. 68 Firebird with the original 400. The last two times I took the car out for a ride, when I got back home and parked the car, I noted ant-freeze was coming out of the over-flow tube at the top of the rad. I would say approximately 4-5 ounces spilled out after my last ride. The temp gauge appeared to be normal. It's an analog temp gauge, thus I couldn't tell exactly what it was reading, but the reading was the same as it always is on any given day, which I would say is around 160 - 180. I can tell you that I had replaced the water pump, rad cap, and thermostat about 5 years ago (180 thermostat). I have probably put on about 2000 miles in the last 5 years. I have not had an over-flow in the last 5 years, except for the two most recent over-flows in the last few days. I can also tell you that the car runs great and I don't notice anything unusual. Any insight as to what the issue may be would be greatly appreciated. Regards, Jay
I get this occasionally too. Gauge reads fine. I attribute it to not having the expansion bottle and it's only when temps in my area are 90ish.. I'd like to hear what others think also.
I'd guess you have something going on causing the coolant to overflow. First I'd look into the things you're doing different, i.e. you running the A/C, drive more city, more up hill or more aggressive. If you're not doing any of these, then I'd look into the things you replaced 5 years ago. Make sure your waterpump is not leaking out of the small hole on the bottom, makes no noise and when opening the radiator cap at start up you can see the coolant flow when the car is starting to get warm. Look into your fan clutch if you have A/C and make sure its tight and won't spin more that a turn or 2 after shutting the engine off. Run the heater making sure the thermostat opens up fully and check the radiator for leaks. Pull the oil dipstick to ensure no coolant in oil - you don't have head gasket issue.
The fluid level is fine, about 3 inches down from the top of the rad cap and has always been at that level with no previous over-flow issue . Strange thing is no over-flow in the last few years, or ever for that matter, just recent over-flow. I will check some of the things that ramair68 suggested. I have A/C, but have never used it or the heater since I have owned the car ( 8 years). I have not been driving the car any differently. All city driving, flat land, no hills. Outside temps in the 80's.
If your car is a driver I would put on the overflow tank. Then all you need is to monitor the level in the tank.
Also, replace rad cap as it maybe letting the fluid leak out. Do you need to top up? Check your oil. If you have a leak you maybe getting air in the system and coolant in the engine.
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When the coolant gets hot it expands. If you have the rad filled to the top the extra volume has to go somewhere, that would be out the overflow tube. Once the coolant cools the fluid level will be somewhat below the top of the filler neck. Maybe your rad cap is no longer holding pressure and more coolant is escaping than normal. I installed an overflow bottle on mine to catch and return the overflow back to the rad when it cools, that keeps air out of the rad. If you put on an overflow tank make sure you change the cap to one that will allow the fluid back in as pressure drops in the rad. Just a thought, I'm not an expert.
Found a few previous articles on this subject. Has anyone else added an expansion tank since these discussions? I would be interested in seeing pictures of mounting locations. As mentioned I think I would prefer the plastic over the stainless so you can see the level.
I have kept mine original and do not have an expansion tank. Radiator is the original style and I do not have a issue with it puking up fluid. I have set idling in traffic for a couple hours in hot temps and ran on city roads with no problems.
