strangest overheating issue

[R3b]

Chimming in because I have the same "issue" on my ka-t with koyo rad and mish fan shroud with 50/50 coolant mix.

Crusing from 2nd-3rd mixed driving on any day in florida from cool 64 to high 90s my temp is at 77-86c the highest (too lazy to convert since my gauge is my fan controller and got used to C)

But soon as I drive highway longer than 10mins over 10miles my temps rises like crazy. I have my fans kick on regularly at 66c but on highway my temps on longer drives 20mins + I get all the way up to 97-98c which is dumb hot for KA without AC I would think. I have AC and cruising its low 90s, I cant even put AC on highway because scared of overheating since its built block. I make 467 so I dont want to have do anything else on the car since its a builtproof daily...

Im thinking its my oem Tstat since a local by me similar specs had similar issue but went nismo Tstat and that helped a lot. He has a more serious setup and recently did an oil cooler which ill do eventually since I want to take longer trips in this soon.

Also big thing is im on e85 and obviously keeps the engine a bit cooler and big temp diffs when im pump.

Besides Tstat and going full distilled with water wetter idk what my highway temps are so high, maybe airflow because of AC parts or maybe need switch to mishi racefans?

[R3b]

double post..........

[Fade420sx]

Originally Posted by KAT-PWR

I had something similar, it was a pin hole in a hose under intake manifold. Finally found it. Would only have enough pressure to leak when hot

I was just wondering where you got the hoses? I’m looking online to fine one specific hose that seems to have a bend right where it connects. got the feeling if I use s flexible hose it might pinch and the coolant won’t flow

[oLemurs]

Originally Posted by Fade420sx

I was just wondering where you got the hoses? I’m looking online to fine one specific hose that seems to have a bend right where it connects. got the feeling if I use s flexible hose it might pinch and the coolant won’t flow

which one man? heater core hoses need to be 3/4" in diameter and look for non kinking lines, all of the smaller coolant hoses are 5/16 and none of them will kink.

[Kingtal0n]

This is such an easy issue to diagnose.

The way to do this is use
random aluminum radiator
and either well known fans (Altima fans)
Or Mechanical OEM clutch fan and shroud

with good water pump and t-stat it will stay cold with proper engine cruise timing and a/f ratio whether its a stock engine or a 500 horsepower sr20det cruising on the highway makes little difference.

Many fans are no good for our cars. Many fans will block airflow more when they are ON while the car is cruising on the highway. Many OEM systems shut down fans for highway cruise. I think even the clutch fan has some kind of RPM bias that helps it slow down on the highway. Bottom line is if using oem fan or well known fan it won't matter though. What happens is people use junk fans that block airflow and don't work well.

I Put a random chinese $75 radiator with $69 Altima fans and it keeps a 5.3L V8 with turbo crossover tube 2" from the radiator 180*F all day

If you think the engine has some kind of gasket problem then pressure test the system. If its leaking into a cylinder then pressurize the radiator with the engine off and then check each cylinder hole for evidence of liquid water. Also perform compression and leakdown tests. Actually I would skip the leakdown. Just pressurize the radiator and see no water, test compression and done. change the fan. Use 100% distilled water if it doesn't freeze there.