Weird Getting Hot

[bigcatchdaniel555]

I was sitting at a traffic light yesturday afternoon when my temp gauge went from normal to almost the h mark by the time the light changed I know the h mark isnt really a good indication of temp but it never gets that high. Anyhoo I pulled into the next parking lot the motor didnt seem too hot i could touch the clock my overflow tank was full it wasnt boiling I grabbed the cap and took it of it foamed a small bit and drained to the overflow. ithought if it was overheating I wouldnt be able to grab the cap. But6 everything back on let it idle for a few minutes and took it home at another light on the waY home I could watch the gauge move. I got home took the cap off again with my bare hands it overflowed slightly when I looked inside the radiator it had no coolant visible. So I added some took the car out and stopped with the car in gear for as long as I could and nothing it stayed at its normal temp. I did this a few times in the drive way on the road and even in the BK drive through it moved the needle a liuttle but thats normally what it would do. Any ideas I didnt see any coolant leaking maybe it wpuldnt draw from the overflow and just kept feed it starving the rad. Thermostat could of got stuck closed or the sender went bezerk for a little while ???

 

[66 Fastback]

The overflow coolant recovery tank will not siphon back into the radiator if the radiaor is not full. Radiators without coolant recovery tanks operate with a normal level that is an inch or so below the top when cool. Radiators equipped with coolan recovery must be full and fluid packed when cool and have additional coolant in the recovery tank.

Barring any leaks, you might just have some air in the system. Keep topping off the radiator when it is cool. Openning the cap when the radiator is hot is more likely to introduce air and also initiate boiling of the coolant both of which will break the siphon to the recovery tank.
Doug

 

[pedal2themetal45]

Sounds like you might have some contaminats in it as it was foamy. Might want to flush the system out real good.
tim

 

[bigcatchdaniel555]

I drove it all day today and it was fine knock on wood. I'm going to Miami on sunday about a 35 minute ride so we'll see how it goes. The rebilt dizzy from autozone was on its way to taking a crap missing and what not replaced that today it also had a BAD exhaust leak on 3 and 4 cyl that is fixed also.
Thanks Dan-

 

[The Plankster Prankster]

another cause of the recovery tank not working is a leak in the line from the rad to the tank. the tank will fill up, but it won't siphon back to the rad. also a bad cap could do it.
and you shouldn't be able to remove the cap from a hot radiator without a big enough steam cloud to seriously burn you.
i did it to a bus several times last weekend, and when there was no pressure in the system, it was easy. but after i fixed the leaky hose and it overheated again, i went for the cap (gloves and bare arms), the steam got to me, so i dunked the glove in a mud puddle, then the steam got to my arm, so i went for a coat, by that time most of the pressure had been relieved and i could get it off without burning myself any more.
if you have little or no pressure, as is evident in the fact that you took the cap off with your bare hands without being burned by a steam cloud, shows that you have a leak. quite possibly your cap isn't holding pressure. cheap easy fix. if that's not it, i would suspect a heater hose, upper rad hose, or the rad itself may have a leak near the top. wherever the leak is, you would still have pressure until the water level is below it.

my truck tries to overheat like that (high reading but no action) whenever i'm struggling to get around in teh snow, but never at a stoplight

 

[bigcatchdaniel555]

The hose is new and so is the rad maybe a year it has some discoloration of the brass on the top so I painted it black to make it easy to find future leaks i'll also go get a new cap thanks.