Running Hot

[killino]

   383 - Auto-A/C-- 160 Thermostat, New 26" Radiator, New water Pump, 30%coolant with Water-Wetter, Fan shroud, and New thermostatic fan clutch, New 4lb pressure cap. Engine is .030 over with "stock" purple cam. Carb is stock thermoquad.  My problem: as I drive down the highway, the temp goes up. If I let it idle, it's fine. Around town, it's fine. Drive on the highway-- TEMP GOES UP! With the A/C on, TEMP REALLY GOES UP! Every coolant part is new and correct. Thermostat functions fine.
    When I re-did the engine, the original steel head gaskets had larger holes for some of the coolant passages. The new steel ones I got from Chrysler, had smaller holes. I thought it was an updated "better" version. Does anyone have a pic of an ORIGINAL STEEL head gasket? What are your thoughts on my overheating problem? Remember, everything is new and functioning properly. I know the cars came with 16 lb. caps, but that still won't prevent my car from getting hot.

[70charger_boy]

Your timing is probably advanced.  Do a search on this forum somebody had a similar problem last week

[Just 6T9 CHGR]

Spring in the lower hose?  this prevents the hose from collapsing @ higher RPM's

I would also use the 16psi cap....pressure raises the boiling point


BTW....how hot is hot?  What is is running?  Stock or after market gauge?

[Chryco Psycho]

is the vacuum advance connected to manifold Vacuum , this is the most common cause of running hot on the highway
disconnect the vaccum advance & set the timing at 36-38* total

[Charger-Bodie]

  and also have someone with a lazer temp gun check the temp right at the senser to see if its acurate ..they sometimes arent

[killino]

Thanks for your thoughts--

Timing is not advanced-- retarding the timing makes it run hotter ( later spark, more fire out the exhaust, more heat in the head)  -Stock is 7.5 deg. mine is at 10deg. 

I am going to get another temp gauge and check it-- I really think mine is accurate-- when I run it on a cool morning, it hovers right around 165 deg.

Vacuum advanced is hooked to proper port on thermoquad.  I checked timing last night and diconnected the vac. line before I checked it.  It never ran this hot before I re-built the engine. 

Does anyone have a pic of an original steel head gasket?  Thanks

[firefighter3931]

New (rebuilt) engines will develop more heat while they're breaking in. I wouldn't be too concerned about it at this point.....at least not until you have several hundred miles of driving on the new build.


Ron

[PocketThunder]

How hot is too hot?  My 440 in my 68 was up to 230º when i was waiting to get into my parking spot at the car show last week.  And when i drive to work in rush hour like this morning it goes up to 220º on the guage and then when i get moving it drops down to about 190º or so.  Am i doing harm to my block at 230º?

Paul

[killino]

Thanks for all suggestions.  Here was my problem: at idle the gauge showed 170.  As I drove it with the AC on or off, the gauge rose.  I shot all parts of the cooling system with an infrared gun.  It tells the temp by aiming a laser at the object.  My rad temp at the top tank was never over 199, even though the gauge showed differently.  I got a new sending unit (again) and all is fine!