uptownfunk

i have rebuilt this engine twice now (d16z6) due to rods being the wrong size....neverless.
i have had to run without a thermostat due to overheating. It ran fine with a thermo before i tore it apart... then after the rebuild the thermo wouldn't open. i have tried 5 different thermos and tested them all on the stove with a thermometer... there all fine. i have replaced coolant with many different processes and still no luck. when it runs the only hoses that get hot are the top hose from radiator to exhaust side of head and the small hose that runs from left side of intake manifold to underneath the manifold to a sensor or valve!?! the heater hose and other bypasses are cold.
what is going on.... if it run great without a thermostat but not with a tested one.... what could keep it from opening?


help, help, help.......this makes me want to hate my Honda....never thought i could say those words!

A-townRacer

thats crazy man you dont have the thermostat upside down do you?

uptownfunk

no... everything is installed properly! all the shops i have been to say something different each time i go. they always blame another component yet these parts work fine w/o a thermostat installed!

gourley

Take the thermostat out, take a heat gun and shoot it at the thermostat for a while. It should heat up the wax inside and cuase the thermostat too open. Thats how you know if its working or not.

uptownfunk

i know they work because i have boiled them on the stove with a thermometer in the water... they all have open at temps they were set at!
this is not a thermostat issue...at least not its basic operation with opening at a certain temp! It wont open when installed... the only thing i could think of was the infamous air bubble issue. that is why i have tried all the different ways of adding coolant (honda's recommended, local shops, manuals, and the internet). if you attempt to run the car with the hose off the thermo housing... you can see coolant come into the housing which leads me to believe that there isnt an air pocket!
i just dont know!
i hope someone has had experience in this matter.

Pothole987

is your fan coming on? my cousin had a problem with his el. the fan switch ( brown 2 wire plug on the thermostat housing ) was not working and made the car overheat.

thesmogman

Well if is not the t-stat we got to look elsewheres.

Blockage in hoses? Or head? Or radiator
Waterpump - fin's broke or propeller came off.

Or the dreaded air bubble, You do know about the coolant bleeder.

That's all that is comming to mind right now.

hebrewhammer

im probably gonna go with blockage somewhere

uptownfunk

yes but it runs fine with the thermostat out... shouldnt that rule out blockage?

kenny707

whats so bad about running with out a thermostat

uptownfunk

not much unless its the dead of winter! i have also read that its beneficial for the engine to heat and cool in the cycle the thermostat provides.

silver-ek4

did you try getting a low temp thermostat?

uptownfunk

yep!!!! tried the two lowest temps and a fail-safe for no reason at all!

hoffmanb16

is this in a EF?

hoffmanb16

just asking cause i had the exact same problem in my old ef.... never did figure it out...

uptownfunk

EG coupe... D16z6 head on a D16y8 block. Of course this started happening after a rebuild with the original D16z6 full engine so it shouldn't have to do with swap.

ByrdB20

this is old i know but did you ever figure out what it was i just rebuilt my b20 and i'm having the same problem

tundra2000

I'v heard and seen on the internet that not having a thermostat migh not get your engine to warm up to its right temp and i also heard that it can cause your engine to over heat because without the thermostat your not allowing the coolant to cool down before it enters the engine again.
Maybe you didn't get all the air bubbles out?

strategy400

My thermostat has a little jiggle valve that has to be positioned right to let trapped air through. Is the jiggle valve positioned right?