boiling radiator!

You'd better find out what it is quick, before you lose the whole engine.

It could easily be thermostat.

Secondly, are your fans working'? Water pump is less likely but is one of the options.

And, it could still be a headgasket or cracked head..Just because you dont see vapor from the tailpipe or oil in the water doesnt mean you dont have a problem. These are common symptoms, but you can have hot gas leak into the water jacket that will boil your coolant away.

thanx for help. i'm thinking head cracked as well! i'm hoping on thermostat of course.

if thermo sticks ...i pressume that would be stuck closed?

If it stuck open, it wouldnt cause overheating.

Could very well be a plugged up radiator. How long does it take to overheat? A stuck thermostat would take a shorter time than a plugged radiator.

Tim

rollup wrote:

It can stick either way. If it sticks open, engine runs too cool. Hurts fuel milage, contaminates oil quicker. But car is drivable. If it sticks closed, now you have a real problem :-(

He said earlier that he had 'flushed the system', which sounded promising but in retrospect, maybe not. I have seen cars that had rubber sheets (from decomposing hoses) in the radiator.

Those can move around, cause severe overheating. But I havent seen this happen in many years.

I think the thermostat should go, first thing. For most cars this is cheap and pretty easy. By the way, there is a new type thermostat available that is claimed to only fail in the fully open mode. If it works, that could save an engine.

Radiators rarely plug "overnight." Usually, they partially plug and the plugged area increases over time until they become totally ineffective. Consequently, the vehicle will progress from running a little warm under some conditions to running hot most of the time to ohmygosh!!

Feel of the radiator after the vehicle has warmed up. A partially plugged radiator will be cool in some areas and hot in others.

Also, run the heater. If it spews cool air when the engine is hot, the impeller may have come loose on the water pump shaft.

Which reminds me of another little trick. If the car is starting to overheat, turn the heater on full blast to take some of the heat out of the system. This can make the difference between limping into someplace where you can fix it and being stuck alongside the road.

You can take the thermostat out, put it in a pan of water and heat it up on the stove. It should open fully before the water starts to boil. If it is stuck closed, in an emergency you can run the car with the thermostat out until you can get a new one. The car won't run quite right, but you won't hurt anything.

BUT... While radiators on large cars/trucks rarely plug, plugging is very common on the small radiators used in small cars.

Jerry

Agreed.... I don't think we have enough info to make more than educated guesses. The radiator is definitely one of the things that could cause this. Plus, it is only a 1.6L engine, which to me, qualifies as a small engine radiator.

Tim

Jerry Foster wrote:

radiator cap not holding pressure might cause those symptoms as well.

The engine would run for some time before the coolant starts boiling off. Less likely with antifreeze coolants.

This is good to know--haven't seen one yet. Sounds like a great design. s

I researched this a little more, SD, and it is called the FailSafe by MotorRad, or some such. Was featured on one of the Two Guys segments.

BUT, in follow up, I found a lot of kvetching about these units. Apparently they tend to latch open with overheating, and may not go back to regular operation. Okay in Texas, but maybe not okay in Nome.

It looks like the electrical gookies are taking a look at this issue too, working on an electrical two speed water pump which will not need a thermostat at all. Economy, blah, blah. It probably costs a ton, fails more often, can still burn up an engine.