Overheat, Brake Shake, Worst Car Enthusiast Ever.

[Derek_Hart]

I'd like to first apologize for [probably] posting this in the wrong section. My Mazda is my first car, and I've had it all of four days. I don't know a thing about cars, except how to fill one up with gas and check the oil.

I've got a fairly keen '92 Mx-3. It starts up fine, idles high, but otherwise does not have too much trouble starting up.

However, when I take it for a spin, after about five minutes of riding at normal speeds, it begins to overheat. By the time I get the car home, I can smell burning all around, and I have to let it rest for 2-3 hours before I can repeat the process. Naturally, I do not do this often.

I've studied the problem elsewhere, and it seems it could be a thermostat in need of replacement, or a head gasket is leaking/broken. How do I check either option without purchasing the other and hoping it works? Is there anything else that could be causing this?

Also, when I begin to brake, the brakes jump around a little. I expect hesitance from any old car like this one, but the pedal and the car literally wiggle beneath me. I looked up another topic with the same problem, but I have no idea what the acronyms mean or how to check the differences between the various 'types of shaking'. Perhaps somebody could clarify for me?

[Derek_Hart]

I doubleposted. Sorry..

I even fail at car forums, see how desperate I am?

[fowljesse]

I'm not technical enough to help much, but I suggest that you post specific questions in the appropriate forums (V6, 4 Cyl, suspension, etc..) Good luck. You'll find the answers.

As for the brakes, look through your wheels to see if the shiny rotor looks grooved like a record. They will be grooved a little, but if you can feel the grooves, you need to have them "turned" at a brake shop. If not, take off the wheels, and see how thick the pads are that touch the rotors. There is a little tab on the pad that you can see that touches the rotors, and squeels when they need replacement.
Check your coolant level in the white box to the right of your engine. It would be a good idea to change the thermostat, anyway. Do it now, and save alot of time and $$. Mine went out, and I didn't have my tools, and it cost over $300 to have a random shop replace it, and towing was free because I have AAA.
I always change all the fluids when I buy a car. It's cheap insurance.

[fowljesse]

Oh, yeah... Change the oil right away. When it overheats, the oil breaks down, and doesn't work well anymore. If you're brave, change the oil while it's hot. It drains more efficiently. Just put a rag over your hand that's pulling the plug, so it doesn't get burnt.

[neutral]

Simplest, cheapest, and most common cause of chronic overheating is low coolant level followed by a thermostat that needs replacing. If coolant level is not the prob, you can ck the thermostat by removing it and placing in a pan of heating water with a cooking thermometer to ck temp at which the thermostat opens. You'll probably see that it does not open, or only opens partway when water temp reaches ~195 degrees F. A properly functioning one opens and stays open at that temp to allow coolant to circulate thru the engine and radiator to prevent overheating. It's a $10 part and worth replacing anyway since you'd have the old one already out of the car. Not a difficult or lengthy do-it-yourself repair and the online shop manual on MX-3.com main page is an xlnt reference guide. Since you are new to car ownership, get a friend to help if ya need the moral support or schedule a visit to your mech to do it.

Are all wheel lugnuts tight? If so, that pedal "shudder," especially when first braking at highway speeds is often a sign that wheel bearings need replacing, usually the front ones. On high mileage cars, as the bearings get worn they allow the wheel(s) to have too much freeplay, maybe not noticeable at steady speeds or under acceleration but application of the brakes causes a change in forces on the axle and so the wheel wobbles. Not a job for the inexperienced and not a safe driving condition. You can put the car on jackstands and check the wheels for freeplay by grabbing the tire at the top and bottom and seeing if there is freeplay. If there is any, the bearings are worn however, I've also had bearings go bad that did not always display freeplay. Recommend taking it to a trusted mech for diagnosis and possibly repair as needed. Just describe the symptoms to the mechanic and let them check the car and tell you what they find as the problem. Front bearing replacement is labor intensive and can be expensive. Post back if ya have Q's or concerns.

[Derek_Hart]

Oh. Excellent. Thanks a lot, guys.

[Derek_Hart]

I changed the thermostat yesterday, but being the brilliant mechanic I am, I managed to somehow break the already-brittle-and-ironically-impossible-to-replace temperature sensor. I went around every dealer within a 10 mile radius (none of which are Mazda dealers. That's an hour ouy of my way) and none of them had any sensor that could replace the one I managed to break. The one that toppled off was a square one-prong, and the ones they kept showing to me were 2 prong'd, rectangle-like sensors.

I'm replacing all the car's juices this weekend, but without the sensor, I won't be able to tell if I still have my OH problem. Does anyone know what size I need, or where I might unearth a replacement?

Another thing discovered while changing the thermostat is that there (in the words of my fiance') 'may be a blockage- hopefully in the radiator and not the engine', because when we unscrewed some nameless silver device on the lower left part of the car, green stuff sprayed sprayed everywhere. Can somebody translate her words into Things I Can Do To See That I Don't Have To Replace The Radiator? I'm not sure exactly what we unscrewed, or what came out, or how she came to her diagnosis, and she's not exactly certain how to check for sure either.

[Aston Wards]

If it's green, then it's coolant. as to what you undid, i dunno, are you talking about the drivers side or the passengers? left depends which way you're facing lol! whatever it is, do it back up n check your coolant level

[onlytrueromeo]

If you can post a picture, that'll narrow it down pretty quick

[Derek_Hart]

It was green stuff, yesh. I'm not sure what coolant looks like/smells like. It kind of squirted out of a sort of silver alien head shape on the passenger side; my left, your right.

And, I'm so technical. Isn't that awesome?

[tehbrookzorz]

Do you have a 4 cyl or v6?

I'm just trying to figure out how you broke something on the opposite side of the engine bay if you were changing the thermostat in the v6. If you have a 4 cyl, I don't know much about those engines.

The brakes may just have warped rotors, which are actually relatively cheap to replace.

[mortenmorfar]

Maybe you have air in your brakes, then the pedal will feel spongy, or there could be grease on your brakes