After head install car running hotter then before.

65-coupe

Well-known member
Ever since I installed the Alum head the car runs hotter. I have a 2 row 1 inch alum radiator with the stock fan. I alsoinstalled an overflow tube. I installed a 3.5" fan shroud yesterday and it still running hotter then before the Alum head. :banghead: Yesterday after getting off the interstate and sitting at a light it peaked at H and would come back down a couple of times. It was about 100 with heat index. My temp gauge does not show temp just C- H. Before and after the shroud it runs just below halfway between C-H. Could it be a bad sensor or does the V8 sensor read hotter. I am running about 3/4 gallon of coolant, water wetter and distilled water to fill it. Not sure what else to do. I thought it would run cooler with the new head. Any ideas.
 
What sort of fan system are you running? Thermostat?
I wouldn't think that the V8 sensor would read hotter.
 
Any boll over? Did you do any check of flow through the radiator core? What thermostat are you using? Are you using more then a 50/50 mix of coolant and water? The stock gauges are not very accurate but there is a way to test them. are any of the other gauges not reading correctly?
 
All gauges working normal. Radiator is about 2 years old( 2 row with 1" cores) with no problems with stock engine. I am using about 3/4 gallon of anti freeze so more water then anti freeze, the rest is Water Wetter and distilled water. No boil over that I have seen. I have the stock 4 blade fan with a 3.5" shroud, 180 or 185 thermostat(replaced last year), Radiator was flushed with good flow. I also changed the pully with a 2V from CI. I have not checked to see if they are different sizes. I will do that tomorrow.
 
Sounds like you covered most of the bases. I would double check that pulley size, then make sure the water pump is actually flowing water (as that sounds like the only thing that might not have been checked.) Are both radiator hoses hot?
About the only other thing that might need to be checked is that timing and carb isn't off, but I doubt that's the deal.
 
The water pump is flowing. When we installed the shroud we had to pull the radiator. So when I refilled it we ran the engine until the thermostat opened to add more water. I am going to see if I can borrow a infrared temp gauge to check the temp.
 
Since you don't have any boil over you more then likely are not running too hot. A better fan (more blades) may help when idling in traffic. You should first get an aftermarket temp gauge and or check the accuracy of the factory gauge so you know temps the engine is running at. Good luck
 
I did not install an Aluminum head. But, I did install the OZ 250 and had the same problem.

Remember, boring the block & changing compression will affect the cooling.

First, I advanced my timing which helped a little.

Then when I flushed my cooling system, I made sure it was burped correctly. When, the radiator is refilled. The engine should be run with the front end raised on jacks or ramps with the heater on and the cap off. This will make sure any air bubbles can be purged from the system. The cooling system is a closed system. So, an air bubble could cause a problem. Also, I am running a 16 lb. cap.

Make sure that you have the fan spaced no more than 1" from the radiator. Also make sure the fan is spaced half way in the shroud and half out. This is achieved with fan spacers. The 3.5 shroud is not doing its job if improperly spaced. Try using the regular stamped steel shroud not the plastic ones made for V8's which have more engine room. I also installed foam in any gaps between the shroud and radiator. If air is passing in between then it will not be effective.

I lastly installed an A/C fan.

When I used to go to Reno, NV in 100+ weather. It used to run hot while in traffic. When the above changes where made it ran cool.
 
Unless the OEM thermostat has one i always drill a 1/8th inch hole in the plate part and index it at 12 oclock to make for darn sure the cooling system burps completely.
Air where there is supposed to be none is a REAL enemy of a cooling system
 
I'd do like everybody else is suggesting but my thinking is the aluminum is a lot better heat conductor. That's a good thing. I think people are thinking that the engine will run cooler - the actual combustion chamber will be cooler which is better because less detonation problems. But the water is going to run hotter because its removing the heat better. Keep in mind the combustion chamber and exhaust ports are now aluminum and surrounded with water jackets. This is a good thing. I would expect the water to be hotter. I don't know if I'd worry if the water is a little hotter. Get a gauge on it and see what it really is.
 
drag-200stang":wck4k4xd said:
I'd do like everybody else is suggesting but my thinking is the aluminum is a lot better heat conductor. That's a good thing. I think people are thinking that the engine will run cooler - the actual combustion chamber will be cooler which is better because less detonation problems. But the water is going to run hotter because its removing the heat better. Keep in mind the combustion chamber and exhaust ports are now aluminum and surrounded with water jackets. This is a good thing. I would expect the water to be hotter. I don't know if I'd worry if the water is a little hotter. Get a gauge on it and see what it really is.


:unsure: Yep, its just like old low compression 70's and early 80's emissions engines, they used more fuel, made less power than there 60's variants, yet needed bigger radiators because they made more heat and ran hotter. The key is that when your engine power goes up, so does your heat. My 81 3.3 makes 92 hp, but uses my old 1982 Cortina 2.3 Cologne V6 radiator from a car that made 114 hp stock. Yet the 3.3 makes 160 lb-ft, but the little 2.3 makes only 130 lb-ft. Its the peak power and fuel use in mpg that governs how much cooling the engine needs. The total hp output defines how much cooling is required, because its very hard to make an engine more than about 23% efficient. So if you had 67 rear wheel hp with a stock 125 hp gross or 85 to 105 hp net 200, then if you boost it to 100 rear wheel hp, or 190 to 200 gross, you'll need 289 2-bbl style cooling. Its elementary.

Sounds like its all going to plan!!!! :nod: :mrgreen:
 
Thanks for all the replies. I bought another temp unit and it shows the temp where it use to be. I am thinking the other one(also new) may have been bad. No issues now so all is good. I will try jacking the front up and running the engine to make sure air is out. I never did have any boil over.
 
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