NEED HELP!!! Car overheating

[VigVoodoo]

OK, the engine is a blacktop S13 SR20DET that has recently been rebuilt with all new oem parts except the following:
BC Street Cams
BC Springs
BC Retainers
BC 0.5mm+ Valves
ACL Perfomance Bearings
ARP Headstuds
ARP Mainstuds
ARP Rodbolts
Koyo Radiator
Greddy Headgasket

Now the problem the car is having is that when the thermostat is installed it overheats, with no thermostat it runs fine. Help is greatly appreciated, thanks!

[ladiesman8527]

have you checked to make sure the thermostat is opening correctly? boil some water and throw the t-stat in and see if it opens up.

[s13gold]

if the upper rad hose is hot and the lower hose is cold.
its clogged.

[B Love]

Get a new thermostat

[Tenchuu]

if the upper rad hose is hot and the lower hose is cold.
its clogged.
+1 easiest way to check

also did you install it correctly? you do realize that you can install it backwards or upside down?

nipple goes to the top, long part goes ion the block. backwards would be hard, but upside down could be easy if you weren't paying attention.

[KA-Owner]

check the radiator and the Thermostat. Also check the Gaskets if they are warned out. Most likely it would be your Thermostat and Radiator..

[s13monkey]

you can also have air in the cooling system did you bleed the cooling system when you swap out the termostat. if not then that could be your problem.

[VigVoodoo]

The system has been bled many times. The thermostat has been changed and checked many times. With no thermostat the system flows and cools perfectly, top/bottom hoses and radiator are hot. With the thermostat installed (long part in engine, nipple on top) the top hose is hot and bottom is cold. What could be the problem?

[VigVoodoo]

I'm still unable to solve this issue.:confused:

[burnsauto]

if the upper rad hose is hot and the lower hose is cold.
its clogged.

The system has been bled many times. The thermostat has been changed and checked many times. With no thermostat the system flows and cools perfectly, top/bottom hoses and radiator are hot. With the thermostat installed (long part in engine, nipple on top) the top hose is hot and bottom is cold. What could be the problem?

you just answered your own question.

did you get a new therm?

[mayco_86]

:x: if it aint any of that check your water pump might not be circulating enough water throught the system when the thermostat is on if the water pump is fine you might have a warped head worst case scenario

[VigVoodoo]

I have tried like 3 new thermostats. The system seems to circulate strong without the thermostat. The head just came back from the machine shop and it checked out fine. Everything but the block and head is brand new.

[racepar1]

Well you are running out of options. It sounds like either the water pump is bad, radiator is losing it's thermal efficiency (yes I have seen this happen, but only on OLD radiators), or somebody screwed up when assembling your engine and the headgasket is bad. If you overheated it multiple times then the headgasket is quite possibly damaged at this point.

[VigVoodoo]

Well the radiator is brand new as is the water pump. This is actually the second new Greddy headgasket I try.

[Gnnr]

What fan are you using? What are you using to measure the engine's temp? Which Koyo radiator is it? What radiator cap are you using? Is it new? Describe the method you are using to bleed the cooling system of air.