Thermostat housing bleeder screw is screwed

katrina664 · 03-21-2008, 04:53 PM

The bleeder screw that is on the thermostat housing has been melted and jammed into the hole. This kicks fluid into the overflow tank.

I have the new screw and working on getting help with removing the old one without trashing the housing, putting a new thermostat in while I'm at it.

Here's the trouble, I bought the flex cap for the overflow tank as it was badly needed and low and behold now the poor thing can suck fluid out of the overflow when necessary BUT the guy helping me says this is not because of the cap but rather because he:

left some old tubing on that engine bleeder outlet and capped it. Then he capped the new tubing coming from the flex cap so there is no longer flow.

I would assume this is right, but it scares me that he insisted on modifying it and besides that I bought the new flex cap for a reason, not to have the system interrupted.

I hope someone on here knows, I have to drive it 30 miles to his shop in the morning to put that thermostat in (must be ordered to the month of manufacture from toyota by the way).

Does anyone know?

Also, guy who keeps overheating, you probably have an airlock because it is a closed system. If you can drain it and refill it according to directions you can find on links here, that may help.

Same guy who capped my engine bleeder valve refused to fill it according to those specs and left it capped so I am having more trouble now than before.

I have always loved toyota, but MR2s are a real bitch

Milfords87MR2 · 04-18-2008, 09:37 AM

Mine was frozen in there, i had to drill it out. Turns out the upper threads were shot, they were too wide for re-tapping. I put some JB weld in the upper threads and let it sit for 24 hours, ran the tap through it, installed a new bleeder valve and it is good as new, no leaks.

Mista 2 · 04-21-2008, 06:29 AM

if you cant get a bolt out and you have a replacement bolt then you could always use olctite freeze release and some vice lock pliers. this combo has saved me on a few projects before.

Jr.Two · 04-21-2008, 06:58 PM

i think this is a stupid question, but...

is the bleeder screw on the thermostat supposed to be open or closed while the car is running ?

mr2tim · 04-26-2008, 04:08 AM

If you'd like a 2nd thermostat housing to work on while yours is on the car contact me I have 4 complete units in the Garage Attic.
(Mark 1's only!)

I'd use a faster thermo up North in snow ?

mr2tim

Silver86 · 06-23-2008, 02:33 PM

MR2Tim,

I'd like to learn how to replace the thermostat in a 1986 MR2.
Can you email me at hengen@earthlink.net? Thanks.

-Paul.

Silver86 · 06-23-2008, 02:47 PM

Can anyone tell me how to replace the thermostat in a 1986 MR2?
The bleeder valve is frozen and the tangs are broken. How do I
get it out? Where can I get a replacement valve? How do I remove
the old thermostat? Thanks.

-Paul.

2restomod · 06-25-2008, 04:20 PM

Quote:

Originally Posted by Silver86

Can anyone tell me how to replace the thermostat in a 1986 MR2?
The bleeder valve is frozen and the tangs are broken. How do I
get it out? Where can I get a replacement valve? How do I remove
the old thermostat? Thanks.

-Paul.

You take off the two bolts holding the thermostat housing together and replace the thermostat with a new one. Just make sure you replace it with the spring facing the same direction! As far as the bleeder screw is concerned---just drill it out or break it out (if it's no good now, like you say) and buy a new one at the dealer (or get one at the salvage yard if you can find one).
Though it's old, Jr2's question about leaving the valve open or closed---it should be open when you bleed the coolant sytem (initially) then closed when you're running the car.

mr2tim · 06-26-2008, 11:54 AM

Dear Paulie,

Getting to the thermo assembly is easy on the N/A cars and not too easy on the S/C cars. (Both use the same assembly in the same way.) it's located atop the transmission.

Word of caution tho bro. There is a blue vacuum switch that has 2 ea 1/8 in hoses that must be very carefully removed. This vacumm is very brittle with age and the tiny plastic tubes break real easy..enuff said..

All the hoses seem to be connected to this assembly and must be removed to facilitate thermo removal.

The thermo assembly comes OEM with a bolt fastening it to the top of the tranny and presto it's loose.

I would strongly suggest replaceing the Thermostat with a OEM unit and not try to use a unit that opens earlier(cooler). Your doing so will affect the computer to read the engine as too cold and begin a process that will degrade the warm-up time and the Ecu gas mixture.

If you send your email address I'll send along some photos to guide you thru this rather easy dis-assembly.

Good Luck

Tim Nusbaum
plandcs@aol.com
mr2tim

2restomod · 07-01-2008, 06:06 PM

Just took a closer look at the thermo housing I got for the SC project and it is totally jammed too. Finally got the valve out and saw that the threads in the housing were actually cross threaded/stripped! How a plastic screw can do that is beyond me, but there it was. Retapped that (1.25x12). Also had to clean out the bore the valve goes in to because rust had pretty much narrowed the hole to the point that the o'ring on the new valve wouldn't go in the hole. Lot of work for such a small peice! Thanks for making me take a closer look at it as this would have been a bitch to fix on the car.

03-21-2008, 04:53 PM	#1 (permalink)
katrina664 No Skills Join Date: Mar 2008 Posts: 11 Thanks: 4 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Thermostat housing bleeder screw is screwed The bleeder screw that is on the thermostat housing has been melted and jammed into the hole. This kicks fluid into the overflow tank. I have the new screw and working on getting help with removing the old one without trashing the housing, putting a new thermostat in while I'm at it. Here's the trouble, I bought the flex cap for the overflow tank as it was badly needed and low and behold now the poor thing can suck fluid out of the overflow when necessary BUT the guy helping me says this is not because of the cap but rather because he: left some old tubing on that engine bleeder outlet and capped it. Then he capped the new tubing coming from the flex cap so there is no longer flow. I would assume this is right, but it scares me that he insisted on modifying it and besides that I bought the new flex cap for a reason, not to have the system interrupted. I hope someone on here knows, I have to drive it 30 miles to his shop in the morning to put that thermostat in (must be ordered to the month of manufacture from toyota by the way). Does anyone know? Also, guy who keeps overheating, you probably have an airlock because it is a closed system. If you can drain it and refill it according to directions you can find on links here, that may help. Same guy who capped my engine bleeder valve refused to fill it according to those specs and left it capped so I am having more trouble now than before. I have always loved toyota, but MR2s are a real bitch

06-23-2008, 02:47 PM	#7 (permalink)
Silver86 No Skills Join Date: Nov 2007 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	How to replace the thermostat in a 1986 MR2? Can anyone tell me how to replace the thermostat in a 1986 MR2? The bleeder valve is frozen and the tangs are broken. How do I get it out? Where can I get a replacement valve? How do I remove the old thermostat? Thanks. -Paul.

06-26-2008, 11:54 AM	#9 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	Thermostat repairs. Dear Paulie, Getting to the thermo assembly is easy on the N/A cars and not too easy on the S/C cars. (Both use the same assembly in the same way.) it's located atop the transmission. Word of caution tho bro. There is a blue vacuum switch that has 2 ea 1/8 in hoses that must be very carefully removed. This vacumm is very brittle with age and the tiny plastic tubes break real easy..enuff said.. All the hoses seem to be connected to this assembly and must be removed to facilitate thermo removal. The thermo assembly comes OEM with a bolt fastening it to the top of the tranny and presto it's loose. I would strongly suggest replaceing the Thermostat with a OEM unit and not try to use a unit that opens earlier(cooler). Your doing so will affect the computer to read the engine as too cold and begin a process that will degrade the warm-up time and the Ecu gas mixture. If you send your email address I'll send along some photos to guide you thru this rather easy dis-assembly. Good Luck Tim Nusbaum plandcs@aol.com mr2tim

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04-18-2008, 09:37 AM	#2 (permalink)
Milfords87MR2 No Skills Join Date: Mar 2008 Location: Rahway Posts: 13 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	Mine was frozen in there, i had to drill it out. Turns out the upper threads were shot, they were too wide for re-tapping. I put some JB weld in the upper threads and let it sit for 24 hours, ran the tap through it, installed a new bleeder valve and it is good as new, no leaks.

04-21-2008, 06:29 AM	#3 (permalink)
Mista 2 Cage Fighter Join Date: Nov 2006 Location: Adelaide, Australia Posts: 463 Thanks: 16 Thanked 21 Times in 21 Posts My Google Map iTrader Rating: (0/0% )	if you cant get a bolt out and you have a replacement bolt then you could always use olctite freeze release and some vice lock pliers. this combo has saved me on a few projects before.

04-21-2008, 06:58 PM	#4 (permalink)
Jr.Two No Skills Join Date: Jan 2008 Posts: 12 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	i think this is a stupid question, but... is the bleeder screw on the thermostat supposed to be open or closed while the car is running ?

04-26-2008, 04:08 AM	#5 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	If you'd like a 2nd thermostat housing to work on while yours is on the car contact me I have 4 complete units in the Garage Attic. (Mark 1's only!) I'd use a faster thermo up North in snow ? mr2tim

06-23-2008, 02:33 PM	#6 (permalink)
Silver86 No Skills Join Date: Nov 2007 Posts: 7 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	MR2Tim, I'd like to learn how to replace the thermostat in a 1986 MR2. Can you email me at hengen@earthlink.net? Thanks. -Paul.

07-01-2008, 06:06 PM	#10 (permalink)
2restomod msnusers.com/mr2projects Join Date: Apr 2007 Location: Queen Creek, AZ Posts: 377 Thanks: 23 Thanked 14 Times in 14 Posts My Google Map iTrader Rating: (3/100% )	Just took a closer look at the thermo housing I got for the SC project and it is totally jammed too. Finally got the valve out and saw that the threads in the housing were actually cross threaded/stripped! How a plastic screw can do that is beyond me, but there it was. Retapped that (1.25x12). Also had to clean out the bore the valve goes in to because rust had pretty much narrowed the hole to the point that the o'ring on the new valve wouldn't go in the hole. Lot of work for such a small peice! Thanks for making me take a closer look at it as this would have been a bitch to fix on the car.