installing thermostat

sd88supra · 11-29-2006, 02:02 AM

my car is running hot again, and given that ive installed a new electric fan, new water pump, tightened my belts and got a block test (no bhg), i have yet to change the thermostat, so im guessing this is my problem. it takes a while to get hot, but even with the fan on and it being pretty cool outside the gauge goes up to red. right after hitting red and accelerating, the needle drops quickly. my guess is the coolant isnt flowing as it should due to a bad thermostat. i got a new one and will replace it tonight under artificial lighting lol. i do however have 2 questions regarding installing a new thermostat.

1. do you really have to drain the coolant prior to removing the old one? im guessing some would spill but i suppose you could just refill whatever fell out (and of course being carefull

2. i got a 180? thermostat, but whats the deal with people drilling holes in theirs? and whats the deal with a brand new thermostat not opening up when first installed? is there anything i should do to it? im guessing these leave the manufacturer ready to be installed but ill let the supra experts guide me. thanks in advance.

jfunez · 11-29-2006, 03:39 AM

no you do not have to drain the system and as long as you install the thermostat with the bleed hole on top not the bottom it'l be ok...

good luck dude...

mrnickleye · 11-29-2006, 06:25 AM

Just put a catch pan under the thermo area to save what spills out. For winter heater use, I use a 195* thermo.

Cut the little dangly off the thermo, and put the hole to the top, with the spring towards the firewall.

Drilling the hole to 4mm helps get the air out of the system. Our cars a NOTORIOUS for getting air in the heater core, cause its the highest spot in the system.

I change from 180* to 195* every 6 months, and by drilling that hole 4mm, I have never had the air pocket problem. You may hear the 'under dash' gurgle some, but the air will bleed out over a few days of driving.

Use a thin coating of silicone gasket sealer on the new rubber gasket, to prevent the NOTORIOUS drizzle/leakage.

After you are all done, start the motor and slowly refilled the system w/coolant, leaving the level to "just" above the core tubes. Let the engine idle for 10-20 min., keeping the level as mentioned. When you start to feel the hot water flow thru the top hose, give it a 2-3k rev on/off a couple times every minute or 2. This will help purge most of the air.

Finish topping up the radiator and install the NEW cap.

Fill the bottle 3/4 full, and check/fill it in the morning to insure you don't run out. The cold engine will suck coolant back into it over night.

sd88supra · 11-29-2006, 07:28 PM

thanks for the info. if i dont ever use the heater, would i need the 195? thermostat at all? i live in san diego where we have nice weather and hot weather. never do i need to turn on the heater.

i do however, need my a/c from late may to early november. my a/c fan doesnt work so im gonna get a new one. however, is there anyway of wiring it so that i can turn it on with the flick of a switch without turning on the a/c? this i think would be a good idea if i was to drive in real heavy traffic when its not hot. i guess a wiring schematic for the a/c fan would help.

j3pz · 11-29-2006, 11:34 PM

this 4mm, where does it need to be drilled?

mrnickleye · 12-01-2006, 11:31 PM

Quote:

Originally Posted by j3pz

this 4mm, where does it need to be drilled?

Just open the existing hole up to 4mm.

mrnickleye · 12-01-2006, 11:34 PM

Those a/c fan(s) operate by relays just below the battery, under the coil (N/A car). I wired in a rocker switch to the ground circuit of the relays to make those fans come on when I want.
I put the switch in one of the coin holder spots on the dash, left of the steering wheel.

ddmcse · 12-05-2006, 11:41 AM

this car does actually boilover and piss water out , or has before and it's not just a wigged out water temp gauge ?

batmmannn · 06-18-2010, 02:23 AM

Whats the little dangle you say to break off? I surely did not do that to mine. I got mine from autozone.I am having similar symptoms, though I burped the hell out of mine. Thinking of pulling it out completely now to see what that does. Mine does not boil over. If I was supposed to break something off I didn't do it, But I can drill a hole. I am considering putting my old one back in. If an NA SUpra has no fan working could that make it overheat even on an 80 degree day? Thanks

11-29-2006, 02:02 AM	#1
sd88supra 3" Exhaust Join Date: Oct 2005 Location: San Diego, Ca Posts: 190	installing thermostat my car is running hot again, and given that ive installed a new electric fan, new water pump, tightened my belts and got a block test (no bhg), i have yet to change the thermostat, so im guessing this is my problem. it takes a while to get hot, but even with the fan on and it being pretty cool outside the gauge goes up to red. right after hitting red and accelerating, the needle drops quickly. my guess is the coolant isnt flowing as it should due to a bad thermostat. i got a new one and will replace it tonight under artificial lighting lol. i do however have 2 questions regarding installing a new thermostat. 1. do you really have to drain the coolant prior to removing the old one? im guessing some would spill but i suppose you could just refill whatever fell out (and of course being carefull 2. i got a 180? thermostat, but whats the deal with people drilling holes in theirs? and whats the deal with a brand new thermostat not opening up when first installed? is there anything i should do to it? im guessing these leave the manufacturer ready to be installed but ill let the supra experts guide me. thanks in advance.

11-29-2006, 06:25 AM	#3
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	Trust Me Just put a catch pan under the thermo area to save what spills out. For winter heater use, I use a 195* thermo. Cut the little dangly off the thermo, and put the hole to the top, with the spring towards the firewall. Drilling the hole to 4mm helps get the air out of the system. Our cars a NOTORIOUS for getting air in the heater core, cause its the highest spot in the system. I change from 180* to 195* every 6 months, and by drilling that hole 4mm, I have never had the air pocket problem. You may hear the 'under dash' gurgle some, but the air will bleed out over a few days of driving. Use a thin coating of silicone gasket sealer on the new rubber gasket, to prevent the NOTORIOUS drizzle/leakage. After you are all done, start the motor and slowly refilled the system w/coolant, leaving the level to "just" above the core tubes. Let the engine idle for 10-20 min., keeping the level as mentioned. When you start to feel the hot water flow thru the top hose, give it a 2-3k rev on/off a couple times every minute or 2. This will help purge most of the air. Finish topping up the radiator and install the NEW cap. Fill the bottle 3/4 full, and check/fill it in the morning to insure you don't run out. The cold engine will suck coolant back into it over night. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08. Last edited by mrnickleye; 11-29-2006 at 06:32 AM.

11-29-2006, 11:34 PM	#5
j3pz 500whp yet? Join Date: Nov 2005 Location: Mechanicsville, MD, US of A, 20659 Posts: 1,060	this 4mm, where does it need to be drilled? __________________ 88 N/A w/ 5spd - stock - not running, bhg 87 turbo/targa w/ 5spd- fidanza light weight flywheel, new oem slave cylinder, apexi air filter, no ac and no heat

12-01-2006, 11:34 PM	#7
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	Those a/c fan(s) operate by relays just below the battery, under the coil (N/A car). I wired in a rocker switch to the ground circuit of the relays to make those fans come on when I want. I put the switch in one of the coin holder spots on the dash, left of the steering wheel. __________________ Had a Red 1989 N/A. Automatic. Sports Pkg. w/wing. TEMS, and some nice MODS. Sold to a friend 10/08/08.

12-05-2006, 11:41 AM	#8
ddmcse 500whp yet? Join Date: Jun 2005 Location: CT U.S.A. Posts: 966	this car does actually boilover and piss water out , or has before and it's not just a wigged out water temp gauge ? __________________ 300+ RW HP Dyno run, jdm,mod turbo,3"exh,electfan,greddyboost Blown HeadGasket info My Supra KiXGaS

11-29-2006, 03:39 AM	#2
jfunez 12psi boost Join Date: Oct 2005 Location: georgia,usa Posts: 338	no you do not have to drain the system and as long as you install the thermostat with the bleed hole on top not the bottom it'l be ok... good luck dude...

11-29-2006, 07:28 PM	#4
sd88supra 3" Exhaust Join Date: Oct 2005 Location: San Diego, Ca Posts: 190	thanks for the info. if i dont ever use the heater, would i need the 195? thermostat at all? i live in san diego where we have nice weather and hot weather. never do i need to turn on the heater. i do however, need my a/c from late may to early november. my a/c fan doesnt work so im gonna get a new one. however, is there anyway of wiring it so that i can turn it on with the flick of a switch without turning on the a/c? this i think would be a good idea if i was to drive in real heavy traffic when its not hot. i guess a wiring schematic for the a/c fan would help.

06-18-2010, 02:23 AM	#9
batmmannn 12psi boost Join Date: May 2010 Location: West Virginia Posts: 320	*Littledangle** Whats the little dangle you say to break off? I surely did not do that to mine. I got mine from autozone.I am having similar symptoms, though I burped the hell out of mine. Thinking of pulling it out completely now to see what that does. Mine does not boil over. If I was supposed to break something off I didn't do it, But I can drill a hole. I am considering putting my old one back in. If an NA SUpra has no fan working could that make it overheat even on an 80 degree day? Thanks __________________ 1987 N/A 7MGE Left Hand Drive MK3 Red 5 Speed and Black Auto Supras My Next project is the Batmobile!

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