engine overheats

[mubienrulz]

Hi!
i have a 1987 toyota camry 4cyl auto. the car moves really well. y'day i heard the water boiling sound from the engine. the temp gauge never goes more than half. i opened the reservoir tank and found hot gas coming out of it. please hel me to fix it. can it be the radiator cap?

[jtmoney]

looks like your out of coolant. refill. if its been a while, its worth the investment for a flush and new components. a new thermostat and radiator cap cost like $10. if you remove the thermostat, you can easily flush your engines coolant passages with a hose. do the same for the radiator. then place new thermostat and refill in radiator. 1 full gallon of coolant will make 2 gallons of 50/50 mixed coolant which should refill the entire system. if your still over-heating, it is a more complicated problem such as fan, fan switch, water pump, or radiator. in general, the engine cooling system is one of the simplest, if not most simplest, system in a vehicle. good luck.

[Doctor J]

Do the "block test" to check the head gasket.

[Dave88LX]

If you haven't replaced your thermostat or don't know the last time it was replaced, throw a new one in there, along with new hoses (if their age is unknown). Very very cheap insurance for simple cheap parts, that can cause very costly repairs or aggravation when they give up the ghost and you're away from home.

Did you check the coolant level?

I'm sure you already know but don't remove the rad cap from a hot engine...wait for it to cool.

[mubienrulz]

the coolant level is fine. i think there is a problem with the cap. when i press the hoses, with a small pressure coolant comes off to the reservoir bottle. then i checked the cap. the surface of the radiator ( where the gasket sit) has tiny chips. is there a way of filling that up?

[Dave88LX]

Well, a new cap shouldn't be more than $4. If the condition is unknown, just replace it and toss the old one.

I'm not following what you're talking about filling up chips though. Are you saying that you've got pits in your radiator where the cap is supposed to seal?

Are you running hot, or actually overheating?

[Kep]

OK, your temp gauge never goes over half, so you're not overheating. You have nicks on the radiator mouth (how did you manage that??). When you gently squeeze the engine hose (at operating temp or when cold?) the coolant flows into the reservoir.

If you didn't have the nicks on the fill tube I'd say get a new cap. With the nicks I might try filling them with epoxy and sanding the surface smooth and try again. (Just how big are these nicks?)

I believe that the standard radiator pressure test kits have an adapter to check the radiator cap pressure release function. However, a new cap would be pretty cheap. If you know someone who'd let you swap caps for a test you could do that as well. I don't think you should notice a coolant flow to the reservoir by squeezing the hose. Though if you do it when the cap is at the overflow pressure (operating temp) I wouldn't be surprised either.

Gotta go,
Kep

[fredk]

his chips are where the cap seals in the radiator, the plastic is brittle

[Kuler2.0]

Since we are talking about cooling systems, I have a question. What would be the easiest way to go about installing a radiator override switch? I want to make it so that I can keep my fan on exactly when I want it to be. Has anyone done this and does it seem to help keep the temp down?
Thanks,
Jay

[Kep]

If I recall, when you disconnect the plug on the radiator temp sensor the fan comes on. That would mean that you could add an interupt switch to one of the wires and turn it on & off. If you left the switch on it would revert back to being controled by the temp sensor.

If your car is running hot (we normally run just a tad over 1/2 way on the gauge) try to figure out why rather than cooling it more. Could be a failing thermosat or a clogged radiator. Or your temp sensor could be bad and sending the wrong temp to your gauge. Even your antifreeze mix can have an effect on temp (50/50 cools better than straight water or even 100% glycol, I understand). Also, an engine running cooler than designed is not as efficient. Your milage may suffer.

Kep

[Kuler2.0]

I am putting it in there mostly as precautionary. The car had a history of over heating before I put a new radiator in and changed all of the hoses. It still doesn't like stop and go very much and I was figuring that the override switch could be used on really high heat days and when I am stuck in traffic. However, wouldn't the interrupt switch turn off my temp sensor (and the gauge) when it was off (to keep the fan on)?

[Kep]

Unplug it and see if I'm right. I'm pretty sure that the temp sensor on the radiator is solely for the fan. The sensor on the engine is for the gauge (he said hopefully...). If it works the way you want it to with the radiator sensor unplugged then you're good to go. If not I am full of ... (not unlikely).

Kep

[Kuler2.0]

Thanks for the advise man. I will check it out and let you know.