can it be my heads?

[drewfever1020]

ok i got a 350 chevy small blcok with a small 465 cam lift!
when i first put my cam my truck ran fine not getting hot at all!
then one day it got hot on me!
so i put in a procomp full core radiator and i put in a new water pump and a new thermostat for 160, but its still gets hot!
i got an electric fan with a switch which i am going to upgrade to no switch soon!
but can it be my heads? i know my engine is good !
do i need new heads?

[CPNEJR]

try flushing the system real good. and not with the quick stuff do it with the stuff you need to run through the system for 20 min. we had a similar problem on our work truck it would get real hot real quick. once i did this we haven't had a problem.

[drewfever1020]

was is it called?

[Ole Blue 68]

1) Make sure your temp gauge and sensor are accurate. (My wire disconnected from the sensor once and came to rest on the header. Sent the gauge through the roof)

2) You might want to go with a hotter t-stat.

[WorkinLonghorn]

If it suddenly started getting hot then the first thing to check is the bottom radiater hose. Grab it and squeeze it and if it is ridgid,fine.If it collapses then it is NFG and you should replace it because the suction from the water pump will collapse the hose,restricting coolant flow.There should be a coil inside the hose that keeps it from collapsing.

[drewfever1020]

i had a 180 thermostat and it still went to 200 when i was at a stop light for a few minutes!
my hoses are good i know the coolant is flowing through cause i have checked it before!

[drewfever1020]

when i squeze the hose does the truck have to be on? i squeezed it right now and the trucks off and it did collapse real easy!

[Ole Blue 68]

Well some temp increase is normal in traffic. Was it still going up or did it level off?

What about your fan setup? Did you ditch the mechanical fan or keep it when you installed the electrics? If not, do you have a shroud for the electrics?

[drewfever1020]

i dont have a shroud my fan blows really strong.
no my temp doesnt level out it keeps going higher!

[68Stepbed]

I have the same issue. My engine has run hot since I installed it. I bought my engine new(GM 260hp crate engine) along with everything else to swap it out. I had a brand new radiator, hoses, belts, wp, fan, fan shroud, t-stat, etc. You name it, it was new. It's always run hot. I've replaced everything at least once. I even ditched the new 3 core rad. for a 4 core and still gets hot in traffic. Just recently, I noticed it wants to run betwwen 200-210 while driving, and still heats up at a light.

I've narrowed it down to it being in my heads.

[drewfever1020]

thats exactly how mine is

[Ole Blue 68]

Well try to rule out all the simple things first since heads are an expensive proposition.

That lower rad hose doesn't sound too good but you can confirm it by checking it while its running. Let it warm up for a while and then hit the throttle (or get a friend to hit the gas pedal) while you keep an eye on the hose.

Also, that lack of a shroud could be a problem too.

[drewfever1020]

so your saying when the truck is runing the hose will collapse when ever i hit the throttle?

[Ole Blue 68]

not exactly but getting the rpms up will trigger a collapse if the hose is bad.

[dznucks]

when you increase the engine rpm you are also increasing the flow of the water pump. when you increase the flow in a system you are going to create a vacuum. this vacuum could be collapsing the hose.

the shroud is very important too. when i put my enigne in i didnt put the shroud on at first during the break in period. i thought the fan was strong enough. the problem with no shroud is that the fan is pulling air from other places, not through the radiator cooling the coolant. yes its blowing air across your engine, but not pulling it through the radiator.

[drewfever1020]

i will consider getting a shroud soon!
and im going to check the hose later today, but for now im off to work! thanks guys!

[70k52wd]

Also, the reason you want to go back to a 180 or even 195 stat is it keep the coolant in the radiator longer to cool it more. The 165 is cycling to fast. It's not letting the coolant stay where it needs to be long enough.

[mclairmo]

I've had a hell of a time keeping my 396 cool but finally fixed it. I fabbed a sheet metal shroud to add to my Flex-a-Lite Black Magic fan so that the fan pulls air through the entire core. I'm running a new 4 row brass/copper radiator. I also sealed the radiator to the core support with foam weatherstripping so the fan would not pull hot air in from the engine compartment and through the radiator. You want only cold outside air going through the radiator. I have a new Procomp aluminum water pump and I'm running a very small water pump pulley, less than 6 inches in diameter and a very large crank pulley, almost 8 inches in diameter. The pulley sizes are very important for keeping the water pump flow high enough at idle. You need the water pump pulley to be smaller than the crank pulley, forget about underdrive pulleys, they suck. I am also running the vacuum advance, which helps to keep the engine cool. I also have ceramic coated headers to keep underhood temps down a little, as opposed to non coated headers. Exhaust manifolds would be even better. I run a 180 degree T Stat and the engine idles at about 190 degrees all day long now. Used to climb past 220.

[cdowns]

r u using antifreeze? just plain water will run hotter than the proper 50:50mix of antifreeze// and 200 in texas in the summer aint really very hot

[WorkinLonghorn]

That's right.That's only 5 degrees hotter than the minimun as set by a stock 195 deg.therostat.

[Ole Blue 68]

200 wouldn't be bad but it sounded to me like he meant it hit 200 and kept going.

[sleepertruck72]

Is your radiator cap also new ? May be too high of psi cap ? along with something else like the lower hose ...

[mclairmo]

Originally Posted by cdowns

r u using antifreeze? just plain water will run hotter than the proper 50:50mix of antifreeze// and 200 in texas in the summer aint really very hot

Antifreeze does NOT transfer heat as well as plain water. Antifreeze is to prevent the water from freezing, to provide a lubricant for the water pump bearing/bushing and to prevent rust. The engine should actually run cooler with 100% water. I ran 100% water with Water Wetter and it was cooler than with 50/50 antifreeze and water. An engine is fine to run at 200 degrees or even 210. If it goes above, then you need to start to worry. I don't think the radiator cap pressure rating will truly affect what temp the engine runs at. The cap rating affects the boiling point of the water. Raise the pressure, you increase the boiling point of the water which prevents a boil over. I have a 20 lb rad cap and it works great. This is why race cars use higher rated caps. However, the increased pressure can start to blow out weak cooling components, like hoses, radiators, etc.

[drewfever1020]

ok i bought a new thermostat 180 and another fan!
so i got one fan pushing and one pulling!
i put the new thermostat on already!
the truck was running for about 12 min and it got to 200, i think i got a real problem here!
my hoses are good i checked them!
everything practictly brand new!
waterpump
thermostat
2 electric fans
im sure its my heads rite?

[sleepertruck72]

Are you sure the temp. gauge is good ?