I left my car at my son's for a month and unknown to me his wife's grandfather had removed the radiator cap and not put it back on correctly. About 30 miles down the interstate I noticed the spray on the windshield and my temp gauge which always runs right under the halfway mark was on H. I pulled over. Let it cool about an hour. Added water and went to the next exit. It ran right where it had but started a little rough. Before I left the parking lot it went to H and I rolled back and parked it. The friend I called tried to drive it but it went back to H and he heard a pop. When we opened the hood steam was coming from under the top ledge of the radiator. I'm a single woman, it's parked right now in a lot. I'm not sure what direction to turn. It's in an area I don't know any mechanics in. If I start calling as a female from out of the area I can already hear the cash register going ching ching. Some background info may help me become knowledgeable enough. HELP please!
This is where we hope that it did not warp the head. Is there any sign of oil in the water or water/antifreeze in the oil dipstick?
The original problem is obvious, no cap pressure.
The extra heat may have fried your thermostat, or more likely, cracked your radiator, especially if it is original, in which case it was probably going to break before long anyway.
When your friend tried the second time, did it overheat almost immediately or take a few minutes? Also, did it drop a large amount of antifreeze/water on the ground or is there still some that you can see from the cap opening?
My first checks would be to see if the radiator is cracked, which will probably be visible on the upper plastic section. Then check the coolant level and look for signs of oil, and check the oil for signs of antifreeze.
I am sure that others here can offer additional help, but you may want to try the miata.net forum as well if you have not already. It is a lot more active than this newsgroup.
What you are hoping for is that you noticed the overheating soon enough that you didn't also blow your head gasket. That's a much more expensive repair than just the radiator. But first of all you definitely blew out your radiator, and you'll have to get that replaced. If you ask the dealership they'll quote you something like $400 for a new OEM radiator. Don't buy that; you can get an aftermarket replacement from any number of parts outlets for about $150. It's not a real elaborate job to pull the old one and put in the new; I wouldn't expect to pay more than about $125 for labor. Good luck!
Thank you for your reply. Yes it was the original radiator. The car is being towed to me Monday and then probably on to a mechanic. From my discussions with a couple mechanics I'm afraid there is engine damage due to it not wanting to idle on it's own after putting the cap back on. I am hoping for the best and the 1st thing I will do before sending it on is check for water in the oil and vice versa. Several friends have suggested I suck it up and send her to a junkyard, they just don't know, lol.
Thank you especially for the aftermarket info. It will be towed home Monday and then on to a shop after I check a few things. Worried but hopeful.......
It's hard to say that there's so much wrong, as the other fellows have pointed out. The part that worries me is that you added water then tried to drive away...If you were evaporating enough coolant to overheat the engine (which I have before!) then it takes a good hour of slowly pouring in mixed coolant directly into the radiator for the radiator, the cooling pipes, and coolant reservoir to fill up completely.
One pours it slowly into a hot engine, because cooling it too quickly might crack the block. You might call that an undesirable effect. The reason you keep doing it over an hour is to give the coolant time to work itself into the whole system.
While pouring into the radiator...the car should be on. This means the fan is running and so is the pump...with the vibration of the car as well as the help from the pump, the air that you discovered does not circulate heat very well will be pushed up and out of the top of the rad.
I'm pretty paranoid about all of this, so I keep jumping into the driver's seat to check the temperature. If it gets to a little less than 7/8 of the gauge, I shut the thing down and wait for it to cool itself enough to pour again.
I know I'm done when the coolant is visible from the rad cap hole, it doesn't sink, and the temp is back where it should be. That's all assuming the rad doesn't have a leak, the thermostat is in working condition, etc. :-P (With the rad leak you probably have, I wouldn't change my prognosis, though.)
The worst thing you might have done is blow your head gasket. This sucks, but it's not...all that terrible. You probably did blow a seal on your stock radiator, though. Depending on the age, it was probably almost time to replace it anyways. Is your car a 97 or earlier? Then, it's time. I recommend Radiator Barn online for the rad. They have great prices, super-friendly service, and the radiator...well, I forgot I installed it! That's a good sign. If you drive a standard, it's okay to get a radiator for the same year for an automatic. They have a higher water capacity, which will make you a bit safer, though it will make the nose around 4-8# heavier.
Hope I could help you, or at least anyone else reading this. Overheating sucks. I've been the one to "make it work" on my own Miata, my sister's old Civic (twice), my friend's car, and given advice on it to many others. It's just, no fun at all.
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