bohica2xo wrote:And there it is.
3 to 5 times a year, every year for the 12 years I have been on this board the same series of questions happens.
1)" My A/C sucks at ide / overheating at idle"
2) Questions about engines, parts, etc. - this can go on for pages.
3) "I got rid of the OEM fan(s) for space / efficiency / because it looks cool"
Finally. The real answer. The incredibly well engineered OEM cooling system has been compromised. Engineers spent significant time on that system. Wind tunnel time. FEA. Testing & refinement.
You have an LS swap. OK, easy enough to understand. Be faster to get answers with that info up front. Any other radical departures from stock? Waterless coolant? Radiator support relocated in car?
Like I said before, internet lore is worse than speed shop customer tech info. A cast Iron block does not "run hotter". The heat you have to get rid of at idle is simply the fuel it takes to spin the assembly. And at WOT, the heat load is still the fuel burned. Aluminum transmits heat better, so an alloy head has a slightly cooler combustion chamber. The Iron block is actually a bonus. It keeps the cylinder walls a little warmer, which reduces friction. In an ideal engine model the cylinder walls would be 275f while the heads would be 200f
Make sure you have enough bypass flow in the coolant path. Blocking a bypass circuit on an engine swap is a common mistake. The cooling system flow within the engine can be significantly higher that the radiator flow.
If the ONLY problem you have is idle cooling with the A/C on, you need to increase heat exchanger airflow. A bone stock car with a bad fan does the same thing at idle. A missing air seal & dead fan clutch in a V6 Ranger would make you look for a blown head gasket - except on the freeway it is cold as ice.
All of us here will be glad to help you through the process. We like Hot Rods. Ice literally wrote the book on Hot Rod A/C. I have done enough engine swaps in my lifetime to make every possible mistake. I was designing Turbo Systems in the late 1970's
My car is factory original as it sits right now, 19 years after I purchased it. Its not an LS swap. The car came with an LS engine and it still has an LS engine. Its just made out of iron instead of aluminum. The only change this car has seen is an iron block was installed to replace the aluminum block. Nobody touched any part of the cooling system. The factory radiator and condenser, lines, shroud, air dam, every single factory part remains untouched on the car.
The aluminum engine was pulled out......every single accessory part was swapped over to the iron block (heads, intake, throttle body, fuel rails, every single factory part that came on the car when I bought it.....except this short block is a 1,500 HP capable fully forged engine. Callies crank and rods, Diamond pistons. And its even a lower compression engine than the factory aluminum block, at 10.2:1.....because its built for boost. The only difference in the factory engine is the metal......its now iron. The day I picked it up at the shop who swapped the engine.....I've had these overheating issues only when the AC is ON.....anywhere other than highway cruising.
So the iron has to be the problem.....iron gets deep heat soaked, aluminum doesn't. Everyone who owns this year model car that goes to iron has higher engine bay temps, and so do I. Everything under the hood is hotter now also. I used to be able to lay my hand across my factory plastic intake after its up to operating temp, about 200*F.........now when the temp gauge still reads 200*F, my hand cannot be laid on the intake or I will get burned. Its because of the iron getting heat soaked and heating everything else up thats under the hood.
The factory cooling system is the same as it was for the last 19 years I've owned the car and never had a overheating issue....I changed to a iron block, and now I'm overheating. Its 114 pounds more dense metal, than the aluminum block.
What else could it be thats causing the overheating when not a single other item was touched or disturbed in any way.....?
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