Still trying to figure this overheating thing out.

[regularman]

After adding the extra cooling and going for a drive the car ran nice and cool, but the temp climbed when I cut it off and left it for the night. yesterday my electric fan came and I bought an adjustable temp switch and a new thermostat for the car. when I removed the gooseneck for the thermostat, pressure blew out. After being not run for a day there was still pressure in the system? Should it not have cooled down and drew coolant back in and filled the system? I am going to pull the radiator out this evening to install the electric fan as a pusher and still have the option of putting my yellow plastic fan back on if more cooling is needed. Not enough room on the front for the electric fan and at the same time I will check the radiator. My dad has taken them apart and checked them before. If it looks to far gone then I will just buy a new one and quit screwing around. I have my other old one and might rip it part too and see if either are worth fooling with. The thermostat that was in there says made in england on it so it is probably the original. It has 74 on it so I guess that means 165 degrees F and the new one I bought is a 160 degree. Whew.

 

[Atrus]

Kim - any chance that you could still be having some headgasket issues? Can't a blown gasket cause massive overheating?

Other than that, I'd say that the thermostat could be bad...sounds like a bad case of heat soak if it climbs when off, but is OK when running. That's the reason some guys run drilled thermostats. It allows the coolant to flow still even when the T-stat is partially or fully closed. Temp probe is near the T-stat though, so I'd assume they should work synonmouosly - if temp looks high, thermo should be open.

I say replace that T-stat, it's cheap and easy!

 

[jlaird]

I would say put the thermostat in a pot of water on the stove and see what temp it opens and leave it on awile at that temp and see if it stays open.

 

[regularman]

That is first on the list, then I thought the electric fan might help because it can coniue to cool when the engine is off.

 

[Trevor Jessie]

OK, I'll bite. Why wouldn't the temperature increase after the engine is shut off? This seems normal to me.

 

[tony barnhill]

While you have the radiator out (& before you do anymore mods), backflush the engine & replace the thermostat.

 

[regularman]

OK, I'll bite. Why wouldn't the temperature increase after the engine is shut off? This seems normal to me.

Seems normal to me Trevor but what does not is the fact that is seems to push the water out when it does this and continue to hold pressure rather than cool off and form a vaccum and pull the coolant back into the system from the recovery tank like it is supposed to do.

 

[regularman]

While you have the radiator out (& before you do anymore mods), backflush the engine & replace the thermostat.

Got a new T-stat to put in. I could hook up a garen hose to the head and squirt water through it the other direction and see if anything comes out.

 

[tosoutherncars]

Anyone tried the 'trick' of filling the rad (or water passages in the block) with cheap cola, and letting it sit for the night? I hear all sorts of scary things get bubbled loose... but I've been a little hesitant to try it.

 

[tony barnhill]

Were it me, I'd backflush through a freeze plug fitting....they make a kit for that.

 

[bugimike]

Kim, what kind of condition is the radiator cap in? A bad one, or one with the wrong pressure rating could also cause some of the problems you describe!

 

[regularman]

Kim, what kind of condition is the radiator cap in? A bad one, or one with the wrong pressure rating could also cause some of the problems you describe!

I tested it and it checked ok. I bought this fairly expensive pressure tester for cooling systems back when the wifes car kept losing coolant and I could not find out where. It has adapters for testing the caps too. It is a 16 pound cap and held about 15 pounds for 30 min, so I guess that is good enough. I would go buy one of them If I thought it would help.

 

[tweety]

Re: Still trying to figure this overheating thing

I have a 1979 1500cc midget. I have had very similar problems.... I'm about 70% sure that it's a blown head gasket. The car overheated dramatically and burned off coolant... Milky oil etc. Luckily there was no indication of problems on the spark plugs.


I used some of the K&L head gasket sealer stuff (the old school stuff in the can, not the expensive fancy stuff in the green bottle) and it solved the problem for about six months. I did it again a few weeks ago and it's holding. I need to make it another year or so before I pull out the engine and trany and rebuild.

the key to this product is that you have to get all of the old coolant out of the whole system which pretty much means you have to do a really really really good flushing of the cooling system. I used the Prestone flush stuff and then ran water through the system. I then filled the system with water and drove it for a mile or two, drained and repeated. Squeaky clean inside.


My car also gets hotter when turned off, I believe that this is normal. The only thing I wonder about in your case the pressure buildup. My gut tells me a good flushing is in order.

 

[tony barnhill]

Re: Still trying to figure this overheating thing

16lbs cap? Isn't that too high?

 

[zimmy]

Re: Still trying to figure this overheating thing

Anyone tried the 'trick' of filling the rad (or water passages in the block) with cheap cola, and letting it sit for the night? I hear all sorts of scary things get bubbled loose... but I've been a little hesitant to try it.

how many pack of Mentos do u use with that? :wink:





on another note.....should i fill my overflow tank,
or do i run it empty?

 

[startech47]

Re: Still trying to figure this overheating thing

We need a picture of the radiator cap. There are different styles. The cap has to have a vacuum vent valve and it has to have 2 seals, one at the bottom of the filler neck and one at the top of the filler neck, in order for it to pull coolant back into the radiator when it cools down.

 

[2091351]

Re: Still trying to figure this overheating thing

7 pound system as I remember.

Steve

 

[regularman]

Re: Still trying to figure this overheating thing

Removed the radiator this evening. Sweated the end off of it and found that the cores don't look too bad. The metal is oxidized but none of that corrosion like you see in prestone commercials. Will put it back together tomorrow after installing the pusher electric fan. Still don't see the big problem. Will also go back with the new 160 degree T stat.

 

[regularman]

Re: Still trying to figure this overheating thing

I think I might have found the problem. Put the end back on the radiator and pressure checked it on the floor by rigging up some hoses and I found several tiny leaks on both of the tank ends. You can't even see these holes, they don't leak fast and I don't think I would have seen them in the car. The pressure bleeds off really slow, I don't know if I would have caught this on my pressure gauge. Time for a new radiator. I think these tiny holes were slowly letting the water out when hot until it boiled. layed down on the side with air on that side they were easy to find, but with water or antifreeze on them they would have only weeped a tiny amount and on a hot radiator would have evaporated before being seen. Now, who has the best price on a new radiator??

 

[texas_bugeye]

Re: Still trying to figure this overheating thing

Make sure you get a new cap and insure its the correct one it makes a HUGE differance. Make sure the primary seal sits proud enough to seal correctly.
The one I got from Moss was wrong! I thought it was 4Lbs?