HELP!! check light came on, boiling coolant, engine overheating
on my way home from lunch, i noticed my check engine light came on and didnt think anything of it. well when i got home, i popped the hood and there was steam everywhere. the coolant was boiling. then i turned the key to the "ON" position and the temp gauge was maxed
I'd check make sure that water pump is circulating water (remove the cap and see if water id movin), and that fans are turning on when it heats up, if fans dont run check fuses, if water not circulating probably replace water pump, could possibly be stuck thermostat as well, if thermostat never opens then water will never circulate.
i dont mind changing the thermostat, i know its easy, but i dont know if thats the problem.
i can see some coolant dripping from the bottom of the car, but not that much of it. i turned the car on and let it run, and i let it heat up almost to the max, and i could not see anywhere that it was leaking. i checked under the car as well, while it was running.
the fan comes on when the a/c is on but otherwise it never comes on even when the engine is well past normal operating temp. sounds like something is wrong with the fan to me, but why would that cause any leaking of coolant? even if the fan doesn't come on, would that really cause the car to overhaet?
Your best bet is to change the thermostat...Mine did that and freaked me out for a couple of days until I figured it out. It should be okay to drive your car IF you run the AC all the time to keep the fan going. The thermostat will only take about 20 minutes to replace and should fix the problem.
Remember kids, I make my living writing software, not fixing cars.
><i>even if the fan doesn't come on, would that really cause the car to overhaet?</i>
I wouldn't think so. Often, on stinky hot days, I'll hear my fan come on once I've backed in to the garage and am about to switch off. This tells me that the fan wasn't on while I was doing 100 MPH, otherwise it likely would still have been on when I was backing in.
So, we're all engineers, here - let's debug your problem.
- you're coolant is boiling
- you have a slow leak, but possibly not when the engine is running
- and that's pretty much all you've told us so far
- not enough information here to conclude any one answer.
So take the following steps in order:
(1) When the engine is cold, is your overflow tank filled to the high mark, and if you take off the radiator cap, can you see coolant right up to the level of the hose that goes to the overflow tank (in other words, do you have the required 8 quarts or so of coolant in the system)?
(2) Is your coolant a 50/50 mix, or is it all water or all rad fluid(which will boil at a much lower temperature)?
(3) Is your thermostat stuck closed? If it is, then the coolant in the block will overheat. Before going to the expense of replacing it, just yank it out and put the hose back on and try running without the thing and see if you still overheat.
(4) As suggested above, is your water pump circulating coolant? If it's not, then the coolant in the block will overheat. Sorry, but I can't suggest a good way to see if it's pumping or not. Perhaps if the engine is running and you have the rad cap off you can see coolant sloshing around? Or, start the engine and keep your hand on the upper rad hose - if the pump is working, you should feel hot coolant going through it after a few minutes. Hey, even better - run it without the thermostat as in (3) above, and you should have coolant gushing out the manifold as soon as you start the engine if the pump is working.
Driving back from lunch I noticed the A/C not producing any cool air. Thought "this is weird, hope the A/C isn't out". Drove for about 3 more minutes then noticed the temp gauge pegged. Killed the engine and coasted into a parking lot. Coolant was boiling in the overflow tank and leaking out it's overflow tube. Waited for car to cool off, filled the engine and overflow tank with coolant, then drove it back to work (about 1 block). Popped hood, left engine running, and waited. Sure enough, it would start running hot but the damn fans wouldn't kick on unless I was running the A/C. Turning that on would stop the temp from increasing anymore but it still wouldn't cool down to normal even with the heater on high.
So I got a ride home and the next morning rented a car trailer. At lunch had a couple of guys help me get the car on the trailer and towed it home with my truck. So now it's sitting in my garage.
I was thinking of bypassing the fan sensors and rigging it to see if it will stay cool with the fans on all the time. If so, I'll replace the fans. Looking at the wiring diagrams for the '92 model I see that the sensors (2 of them) are at the bottom of the radiator. I wonder then if my thermostat isn't just stuck closed and the coolant in the radiator isn't warming up. Strange since the top hose is firm and hot.
So maybe I'll change the thermostat first and see if that fixes it. I'm in the middle of getting all the 60K service parts now mailorder (car now has 70K, oops!) and was planning on changing the thermostat and water pump anyway. So maybe I'll just get raped on getting the tstat locally and change that first. Heck, I can't even drive the car to a mechanic now anyway to get the other stuff changed until I figure out what is causing this damn thing to overheat!
I did some checking and it doesn't look like the engine is toast. No water or steam coming out of the exhaust, no apparent coolant in the oil or oil in the coolant. The engine will still pull coolant from the recovery bottle when it cools. So hopefully the headgaskets and heads are OK. I think I only drove it less than a mile and for only a few minutes at that temp, so hopefully it'll be OK!
'92 Stealth RT/TT
Feelin' the need for more boost!
2001 F-150 SuperCrew Lariat 4x4
And a list of mods for both that will have me busy (and broke!) for months!
yeah, i'm thinking thermostat too. i think i will change it next week, i am leaving tomarrow morning to go to Kentucky with a friend of mine for a Beretta meet. i know, a BERETTA, but his car IS nice. lots of custom stuff, gutted interior (no back seats, carpet, center counsel, etc.). it hangs with GT Mustangs, not bad for a Beretta! should be cool, there will be 1/4 mile strip and stuff. thanks for the input everyone
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