Just installed a JDM D15B motor into my 91 hatch. I bought a new radiator and it starts to over heat. My friend and I noticed the fan switch was crack but the two pins were still intact. So we left it plug in. When I got home my reservoir was BOILING full with antifreeze?

Ill post some pictures tomorrow..

 

need more info are the fans coming on? did you make sure you bled all the air out when you intalled it? did you run your motor on the old rad ?

 

the fan relay maybe
when you put the new rad in did you let the water curculate ??

 

ok..

a. does the fan come on or not?
b. is the car actually overheating or is there just bubbles in the overflow?
c. is having too much water in your coolant a possibility?
d. did you purge the air out of the system for a few mins with the rad. cap off

 

I'm betting you forgot to bleed the air out of the system

 

yeah i bled the air out and the fan does not turn on.

 

well it might be the fan switch

 

Thermostat?

 

first thing that comes to mind for me is "new motor" and "boiling over res" when my head gasket went bad. my res boiled over so quick cause of the exhaust leaking into the coolant, and would overheat in like less than a minute. i replaced the head gasket and it stopped.

could be a very slight head gasket leak.

 

yeah it was the thermostat. the coolant isnt cycling.. So Im buying somebodies thermostat from a D16. Will that fit my motor?

 

your buying a used thermostat?? wtf?? theyre like 10 bucks new! and yea,,,that shizz will fit. but unless its new dont buy it....

 

oh. lol i thought it was that big peace, where the hose and fan switch connect to.

 

wtf? well the thermostat is inside there..behind what is called the thermostat housing...which the switch threads into. soo take that off and replace the stat. also you said the cooling fans fail to kick on?? theres yo overheating problem.! check the switch and check the fans to see if they even work..connect em to the battery or somethin

 

i bought the new switch yesterday too. but it wasnt turnin on either..

 

Your car is overheating because the fan isn't turning on. Fix the fan. Trace your wiring back, check your fuses aren't blown, check where you are getting power up until. Check if the fan motor works.

 

Just FYI water has better cooling properties than antifreeze so having more water in teh coolant would not cause an overheating situation.

 

never said that it would genious. too much water in the coolant system WILL however lead to it boiling out through the overflow tank. hence why i asked if too much water was a possibility after asking about the bubbles in the overflow.

 

Whoa now, no need to get butt hurt and call names. Simple misunderstanding. Yes it is true more water lowers the boiling point as well as raises the freezing point.

 

thanks for the help. i got it fixed. the last spot i ever check was the THERMOSTAT. -_-

 

doh...

 

Did you fix the fan?

 

yea

 

bad water pump?

 

negatory