overheating problem, please help

[Joe Vandatta]

I am begining to suspect you have a cracked head if you have ruled out head gaskets, etc.

[66bird]

Hey sorry i havent been on in a long time. First of all when "old faithful" blows the temp gauge goes all the way to the right then rapidly drops. Well i havent solved the heating problem. But im trying dual electric fans. Also my head gasket is leaking so i have to replace that. I have no clue what the heat riser is or is doing. Ill look into that. I dont believe its a cracked head. Atleast i sure hope its not. Thanks for your help

[CANNEDBAND]

its very simple to chack the heat-riser.make sure the eng is cool enough to touch the ex. manifolds.the heat riser(if it hasnt been removed.)is located on the left-hand side ex. manifold,just where the H-pipe bolts on.Youll see a circular cast iron object that should work freely and "spring back"when you release it.

[JeffMedved]

I am curious to know if your electric fans resolved your overheat problem. I have a 67 Landau that runs hot in the summer. Granted we are in the Southern Nevada desert here. I have replaced the radiator with an aluminum radiator and has a new water pump. The engine was rebuilt about 1000 miles ago. The engine runs what I feel is a bit warmer than it used to, but with the A/C on at idle, or a stoplight, it overheats. The A/C has been converted to R-134A. I was told that converted systems run hotter at the condenser than R-12 systems, but I dont know if that is accurate or not. Anyhow, I really want to resolve this issue, and I have considered an electric cooling fan, but I am unsure of what CFM rating is necessary to meet the necessary cooling. I am sure that an electric fan would probably resolve this issue, as it would pull a lot more air at idle than the standard clutch mechanical fan. Though, I would really like to know the cause of all of this.

Has anyone else converted their A/C to R-134a and noted an increase in idle temperatures?

Anything else that anyone else can offer would be appreciated.

I can be emailed direct at [email protected]

Thanks for responding in advance.

[boaterbob]

Most garages can put preessure on your system to check for a high pressure leak. Also how old is your radiator? Sometimes it may look good but not have proper flow and flushing it at home don't work. You could pull it out and have the flow checked at anny good radiator shop. I used to have trucks and sometimes they took the tanks off and rodded the cores to get the barnicles out and put them back together. I don't think they do that to small car radiators.

[JeffMedved]

Radiator is brand new (aluminum 2-rows 1 inch tubes). Flow-kooler water pump and RobertShaw 195 degree thermostat. Engine was rebuilt about 1500 miles ago. Car seems to run fine until I turn on the A/C and when I get to city stop and go traffic, it gets hot (to the 'P' in temp and beyond.)

The A/C is causing the overheat issue(s). I had the system converted to R134a and was wondering if that might have caused the issues? I am dumbfounded on what the cause of this is and where to find a solution. I am pretty much out of ideas.

[boaterbob]

Are you pulling enough air through the core at idle? I put a radiator with more tubes in a 56 chevy. It worked well while going but the fan could not pull enough air through the extra restriction from the diffrent core configuration.

[JeffMedved]

I did a complete review of everything under the hood. I came to the conclusion that I had been treating the symptoms of the overheat problem and not trying to fully investigate the cause. I think I may have found it! The exhaust control valve at the right manifold appears to be rusted and stuck (won't now for sure until I take the pipe off). However, this valve is designed to redirect exhaust heat through the intake and out the left exhaust pipe, to help warm up the engine in extreme cold climates. This would, if stuck, definitely make the engine run a lot hotter.
To be on the safe side, I ordered a replacement spacer to take the place of this valve from T-Bird Sanctuary, and it should be here by week's end. I will take the old valve out and inspect it and replace it with this spacer (in the southern Nevada desert climates, I don't image I will have too many issues with sub-zero temperatures!)
I will let you know how this all turns out. This valve, if the cause, was probably the cause of the overheat in the original post on the '66 T-Bird that started this thread posting.

[JeffMedved]

Well, its good and bad news. The valve was stuck, unforunately, it was stuck open. So, this was not the problem! So, I guess I am still searching for answers. I am taking the car in Monday to a diagnostic center to check compression and see if (he) can figure out what is causing my running hot issue. I will keep you updated.