Does anyone have any ideas on this?
72 small block auto/ air/ etc.
Fresh built motor. new gm water pump. Moroso 160 thermostat. Be cool dual electric fans.... come on around 160.
2 bottles of water wetter along with standard mix antifreeze/water.

70 mph with no a/c running..... 235 degrees!
yup, its real, double checked it with another electronic thermometer.
Was running a 180 delco, same problem.
Water appears to be circulating well enough.
I was wondering if anyone has the solution to this.
I guess one route is to get the BE Cool set up, but thats big bucks, but I cant drive it like this.
Any help or suggestions would be appreciated.
I do know that the fans are pulling the air through the radiator.
I have checked about everything I know to check.

 

235* just curious what you were pointing the gun at Vents, floor, etc?

You probably already check this but the vacuumed control actuator on the plenum door behind the kick panel on the passengers side might be open this door allows heat from the engine in when you select heat on the control, I say this because mine was stuck open and I wasn't selecting heat, also my cowel plenum was stuck open behind firewall/blower. My a/c doesn't work so I was getting really hot just pushing the 200* air from the engine into the car via ducts and plenum door behind kick panel on passengers side. To boot I have some firewall holes to still fix but these two venting doors fixed my hot air coming from ductwork problem... Got alot of help on this from some of the members here... Like I said you may have already looked into this.

 

FIRST thing to do is pop the stat out and run without one....second thing to do is make damn sure your lower/return hose has a GOOD spring inside it so it don't collapse under large water demand/suction....

after those two things report back as to what is results....

PM me as I maybe miss this thread....I too have a '72 a/c vert 350 but mine is now a hotrod, and no problems here in FLORIDA even.....

so your problem is minor, me thinks.....

 

with the lower hose thing, good possibility. Pop the T-Stat and see what happens just to make sure its opening, if it is in fact ok you will have the same problem.
Make sure the Air Dam is on place and working, make sure the radiator seals are all in place.

 

Thats engine temp, not inside the car.

I have run 2 new tstats, one gm and the other aftermarket.

I have a new GM lower hose, but I know that doesn't mean much.

 

The problem is not likely your thermostat if you have been through 2 and going less than 180 is like pressing the elevator button more than once. It may make you feel better, but doesn't bring it any faster.

I believe that the most often overlooked item when an engine runs hot, but not so hot as to overheat, is timiing. I bought my 427 last summer and just running down the street at 40 mph it would quickly get to 200-210*. That same engine is now a 496 and even if I really lean into, I only get to about 190; 200 if I am really mean to it. Normal driving gets me 180*. And this is with a small block radiator and I haven't put my little spoiler back on yet either.

What is your initial timing set at? How much mech advance? Is your vacuum advance set up?

You should definately check for obstructions, such as hoses and t-stats, but you don't need gimmicks, such as water wetter and the like to get a properly set up small block to run at 180*. If your timing is at 36* all in and you are running at 235, you have a blockage somewhere and need to find it. If your timing is substantially less than this, you need to read the timing sticky and experiment a bit and see if it impromves. If it does work on this. If not, start troubleshooting the blockage or other reason for running hot.

It is a known fact that retarded timing will cause your engine to run hot. Heck, when I fired up my rebuild and was breaking in the cam my headers turned orange because I didn't have enough timing in it.

Good luck

 

Not sure if I missed it, but what's the history for your radiator? Type/size/age/condition? Also, with the electric fans, what kind of shrouds are you using to force the air to move through the radiator? Are you sure the system is full of water/anti, my BB has a really bad problem with not filling completely. Once filled it runs "cool". Is the AC condensor in good shape and not blocking the air flow? Has someone "painted" either the radiator or condensor. Wrong paint, filled air passages, no cooling. Is the "front end" (everything in front of the condensor/radiator) original, open to air flow?

Just a few more things to consider.

Andy

 

At freeway speeds you should have sufficient air flow. You have a new water pump. I believe your radiator is not up to snuff. I have been there a million times; recently in fact.

 

Thanks for all of the advice.
I guess next step is to check the timing.
I could have heard a little spark knock, but with the header/sidepipes, its really hard to hear it.
Anyone else?

 

Make sure your radiator is 100% sealed to the surrond and that your shroud is 100% sealed to the radiator.

If either is installed with available sealing kits there will be HUGE air gaps that need to be filled. You'll want ZERO air gaps between the various pieces.

 

I have to agree , the fan shrouds are really important !! Also the rad hoses, ,my .2 worth! Ron

 

Running warm at highway speeds is usually an indication of a bad radiator. Heating up at idle and in traffic is more fan related.

 

Is Your Tranny Shifting Out Of Low Gear At 70 Mph If Not That Will Make The Motor Run Hot!

 

If your timing is OK then before you do anything drastic you might want to try this..........raise the front of the car, drain out a little coolant so it's below the intake, remove the thermostat and then fill the block and top hose thru the thermostat hole. I had a heck of a time with trapped air in my block that was causing an overheating condition I couldn't figure out. This solved the problem.

 

I'd had trouble filling my '69 BB ever since I'd bought the car. It'd overheat at the drop of a hat. A mechanic friend told me to drill a small air hole in the 'stat, remove the upper radiator hose, and fill the system using the top rediator hose opening. Watch for the water in the 'stat housing. Worked great. The car actually runs "cool" now.

 

Maco, this might sound insulting....but are your fans wired the right way??? You woundn't be the first person that had an electric fan spinning the wrong way The funny thing is the engine will run cool at slow speeds because the fans move enough air but at highway speed they just work against each other. I have Duals in my 82 w/ over 100k on the radiator and w/ the A/C on I run a cool 200 in the summer.