Overheating - Looking for suggestions

[Jim Yergin]

Drove my car on its first tour yesterday. About a 275 mile round trip with seven other woodies. Had a great time but had some overheating problems. Had to stop repeatedly to re-fill the radiator. Usually more than a gallon and a half low after driving about 45 minutes on the highway. Obviously I am losing coolant either through a leak or boiling off. Temperature gauge would indicate high heat very quickly after re-fill and would not go down while driving even with increased air flow through radiator. The engine has about 1200 miles since I rebuilt it with the block hot tanked and the water distribution tube replaced. At that time the radiator was also flushed and the flow checked by a radiator shop. I just replaced the water pump and I also checked the thermostat in a pot of hot water to make sure it was operating correctly. I do not see any evidence of leaks when the car is at idle. I also do not see any white smoke out the tail pipe to indicate a leaking head gasket. I have checked and adjusted the timing without any effect. I also double checked the tightness of the fan belt. I am going to go through all of the hose connections again to make sure they are tight. Just wondering if anyone has any suggestions on what else to look for.

Thanks.

Jim Yergin

[desoto1939]

Jim:

Is there any possibilyt that one of the bottom hoses from the waterpump back to the radiator might be collapsing on when when it gets hot and then this is causing the water to boil over and then go our the overflow?

Did you replace the hoses or did you us old hoses. This is just a thought. I know the bottom hose does not use a spring to prevent collaping but this might be something that you might consider.

rich

[Don Coatney]

Jim;

Have you used an external thermostat to confirm you are actually over heating? Could be a calabration issue with your in dash thermometer. When you need to add water if you remove the cap and look inside is the level below the top of the radiator core? These non pressurized cooling systems will release water through the overflow tube IF the radiator is too full. In other words they will see there own coolant leval.

The temperature here in the Boro was over 90F yesterday. If my car sits in traffic for any length of time the temperature gauge (I have an aftermarket gauge) will clime to around 200F. If I am making the engine work really hard climbing a long hill the temperature will also climb to the 200F range. Normal driving on level ground at road speed (70MPH in overdrive gear) my temperature normally runs right at 180F.

Last Friday leaving the Friday night cruse in here in the Boro I got in a race with a Hemi powered 56 Desoto heading home on the interstate. The guy was right on my bumper and pulled a slingshot at about 80 and passed me. I dropped the hammer. When I passed him my tach was reading around 3500RPM's in overdrive gear. This calculates to around 95MPH. The ambient temperature was around 85F and my engine did not go above 180F at that speed even though I was working it really hard.

Edited June 4, 2009 by Don Coatney

[Plymouthy Adams]

with that much coolant loss you seem to have a problem for sure...with the block hot tanked and new dist tube and new pump..I think I would be looking at the radiator as suspect...how many GPM did the radiator flow...even a bad radiator will void itself of water but the true test is in flow..each and every radiator is designed to flow x amount of water and these tables and data are usually found at a quality radiator shop. Aslo that same shop will hook your radiator up to the flow tester..it works like this..water inlet connected..radiator cap off..lower outlet free to flow without a hose...turn on the water and increase the input till the radiator is full just to the neck of the fill hole and adjust flow to maintain this water exchange...read the flow meter for input as this exchange is regualted by the radiator voiding itself...remember this is flow..there is no pressure for the cap is off the top...I do not trust any shop that does not flow test a radiator...

other items not mentioned is critical also..the slight advance of timing is critcal to running cool...doing a pressure test of the cylinder with a full radiator and check for bubbles..as this amount of coolant disappearing in absence of a visual water leak could indicate out the exhaust steam..however if you are just flat boiling over..you are not properly exchanging your heat at the radiator..it would not be likely if you do indeed have a good thermostat that the water is moving to fast and thus not exchanging heat..if however it is not moving fast enough through the radiator..you are cavatating in the lower hose and sucking air to the pump with the engine getting to hot...thus when idle the water not being pumped is returned to the block and super heated thus the immediate boil over ...

Edited June 4, 2009 by Tim Adams

[greg g]

I had a similar deal years ago with a Volvo, lost coolant then overheated. couldn't find the leak for the life of me. Changed the hoses, the thremostate had the radiator tanked, o change. Finally one day I opened the hood just after driving it on a cooler than average day, and saw a trace of steam at the very back of the motor, turned out there was a pin hole leak in the heater hose, the coolant was spraying against the firewall but only whent he car was running, and it was hidden so that you couldn's see it. Does it run cool when refilled and driving around town? Or does it over heat even whe full?

[Joe Flanagan]

I had the same experience as Greg. It was a pinhole that you had to look at really hard to see but it raised heck with my engine.

Don, does your wife know that you're out racing cars on the freeway? I didn't know you were a Rebel Without a Cause.

[Joe Flanagan]

By the way Jim, this has got to be the absolute last bug, right?

[Don Coatney]

Don, does your wife know that you're out racing cars on the freeway? I didn't know you were a Rebel Without a Cause.

Lisa is in Indiana grandmothering. I have not seen her in 3 weeks. And it will be another two weeks before I do see her. Rebal....yes, cause... I wanted to wup him....

[Joe Flanagan]

And who knows what you'll be up to at the end of another two weeks. Probably smoking cigarettes and carrying a switchblade. You'll have to get rid of all evidence of this behavior by the time she gets back.

[Plymouthy Adams]

@$#% &*$@ kids need to grow up...

[Don Coatney]

I do have a switchblade tucked away somewhere.

[Plymouthy Adams]

I know you a big boy Don..but a switchblade..at a gunfight..?? not real smart..have Ruger will travel..lol

[Jim Yergin]

Jim:

Is there any possibilyt that one of the bottom hoses from the waterpump back to the radiator might be collapsing on when when it gets hot and then this is causing the water to boil over and then go our the overflow?

Did you replace the hoses or did you us old hoses. This is just a thought. I know the bottom hose does not use a spring to prevent collaping but this might be something that you might consider.

rich

Rich,

The hoses are new but I will double check the condition of the lower hose.

Thanks.

Jim Yergin

[Jim Yergin]

Jim;

Have you used an external thermostat to confirm you are actually over heating? Could be a calabration issue with your in dash thermometer. When you need to add water if you remove the cap and look inside is the level below the top of the radiator core? These non pressurized cooling systems will release water through the overflow tube IF the radiator is too full. In other words they will see there own coolant leval.

The temperature here in the Boro was over 90F yesterday. If my car sits in traffic for any length of time the temperature gauge (I have an aftermarket gauge) will clime to around 200F. If I am making the engine work really hard climbing a long hill the temperature will also climb to the 200F range. Normal driving on level ground at road speed (70MPH in overdrive gear) my temperature normally runs right at 180F.

Last Friday leaving the Friday night cruse in here in the Boro I got in a race with a Hemi powered 56 Desoto heading home on the interstate. The guy was right on my bumper and pulled a slingshot at about 80 and passed me. I dropped the hammer. When I passed him my tach was reading around 3500RPM's in overdrive gear. This calculates to around 95MPH. The ambient temperature was around 85F and my engine did not go above 180F at that speed even though I was working it really hard.

Don,

I have not used an external thermometer to check the temperature and do not know the accuracy of my gauge. According to the gauge, after refilling the radiator it would run about 180-185 for a short time before rising beyond that. When I stopped to refill and took off the radiator cap, the water was boiling. The speed of the car and the amount of work being asked of the engine, etc., had no effect on the temperature readings. I know about the overfilling but it took so much to refill before it even covered the core that I don't think it was merely a matter of it "finding its own level".

Jim Yergin

Edited June 4, 2009 by Jim Yergin

[Jim Yergin]

with that much coolant loss you seem to have a problem for sure...with the block hot tanked and new dist tube and new pump..I think I would be looking at the radiator as suspect...how many GPM did the radiator flow...even a bad radiator will void itself of water but the true test is in flow..each and every radiator is designed to flow x amount of water and these tables and data are usually found at a quality radiator shop. Aslo that same shop will hook your radiator up to the flow tester..it works like this..water inlet connected..radiator cap off..lower outlet free to flow without a hose...turn on the water and increase the input till the radiator is full just to the neck of the fill hole and adjust flow to maintain this water exchange...read the flow meter for input as this exchange is regualted by the radiator voiding itself...remember this is flow..there is no pressure for the cap is off the top...I do not trust any shop that does not flow test a radiator...

other items not mentioned is critical also..the slight advance of timing is critcal to running cool...doing a pressure test of the cylinder with a full radiator and check for bubbles..as this amount of coolant disappearing in absence of a visual water leak could indicate out the exhaust steam..however if you are just flat boiling over..you are not properly exchanging your heat at the radiator..it would not be likely if you do indeed have a good thermostat that the water is moving to fast and thus not exchanging heat..if however it is not moving fast enough through the radiator..you are cavatating in the lower hose and sucking air to the pump with the engine getting to hot...thus when idle the water not being pumped is returned to the block and super heated thus the immediate boil over ...

Tim,

I don't know the GPM. I merely relied upon the shop telling me it flowed OK. So that may be the problem. I appreciate the suggestion. I have tried different timing settings without any resulting changes in the coolant temperature. I have it slightly advanced right now.

Jim Yergin

[Jim Yergin]

I had a similar deal years ago with a Volvo, lost coolant then overheated. couldn't find the leak for the life of me. Changed the hoses, the thremostate had the radiator tanked, o change. Finally one day I opened the hood just after driving it on a cooler than average day, and saw a trace of steam at the very back of the motor, turned out there was a pin hole leak in the heater hose, the coolant was spraying against the firewall but only whent he car was running, and it was hidden so that you couldn's see it. Does it run cool when refilled and driving around town? Or does it over heat even whe full?

Greg,

That is interesting. It runs cool for a short while after refilling but then heats up whether I am driving on the highway or just around town. I will have to look more closely for any signs of leaks. Would a pin hole allow a gallon and a half to be lost in such a short amount of time?

Thanks.

Jim Yergin

[Jim Yergin]

I had the same experience as Greg. It was a pinhole that you had to look at really hard to see but it raised heck with my engine.

Don, does your wife know that you're out racing cars on the freeway? I didn't know you were a Rebel Without a Cause.

Joe,

How did you locate the leak?

Thanks.

Jim Yergin

[Reg Evans]

Do you have the proper water pump for your either internal or external bypass system?

[Jim Yergin]

By the way Jim, this has got to be the absolute last bug, right?

Joe,

Is there such a thing as the "absolute last bug?"

After this, I still need to get the O/D to work properly as well as get my hood fitted correctly, but I am getting there.

Jim Yergin

[Jim Yergin]

Do you have the proper water pump for your either internal or external bypass system?

Reg,

Good question. Surprisingly for me, I did make sure that I had the correct pump for my external bypass system.

Thanks.

Jim Yergin

[Joe Flanagan]

Jim,

I found the leak accidently. I was just looking all around the engine compartment and I thought I heard a funny sound and there was this geyser that was so tiny you could barely see it. It was mostly steam. But I doubt a hole like that could empty that much water in such a short time. Didn't your car run fine before this? I wonder why it started all of a sudden. I like Tim's suggestion about the flow of the radiator. Maybe some leftover crap worked itself loose, started circulating through the system, and is now lodged in your radiator.

[Jerry Roberts]

[quote=Jim Yergin;...<snip> I just replaced the water pump ...<snip>

Jim , Did you replace the water pump just after or before it started running hot ? If you replaced your pump and it then started to run hot , can you put your old pump back on to see if it will run normal ?

Edited June 4, 2009 by Jerry Roberts

[Frank Blackstone]

How about an overnight pressure test of the cooling system. Seems to me that might reveal even a pin hole leak.

[Rodney Bullock]

I do have a switchblade tucked away somewhere.

A switchblade:cool:This guy has a butcher's nife:eek:

After riding with Don there is one thing for sure, He ain't backing down from no Hemi! Hey Joe Don is so experienced now by the time the wife gets home all evidence is long gone:rolleyes: I long for the old days.

[Rodney Bullock]

Jim, Two questions. While you were working on your trans did any of these symtoms reveal themselves? When you checked your timingwas the car hard to start?

When you start your car, have the radiator cap off. After a while you should see the water curculating. Rev the motor and look at all hoses. Do they move? Check your oil is it over fulled? Take a look at your heater core did you shut off the valve that supplies it water in the winter? could it be leaking? If there is no visible leak then maybe your mixture is to much water and it's evaporating. The water or fluid has to be going someplace. These problems are easy to find on our old motors however you will have to put yourself out there to find them. We have had alot of rain lately so the next dry day drive it and observe, you have done such a great job it's right under your nose. A rebuilt motor does run tight at first the stude did, what weight oil are you using have you changed it and added your ZDDP plus?