FJ40 Thermostat Installation How To

[ToyotaMatt]

Nope, it’s yours in my book.

@S.CarolinaFZJ80

 

[jestlurnin]

@ToyotaMatt you got a part number for the nut that would go on the studs for the thermostat housing?

 

[ToyotaMatt]

@ToyotaMatt you got a part number for the nut that would go on the studs for the thermostat housing?

Stand by

 

[ToyotaMatt]

Nope, it’s yours in my book.

@letterman52
I cant take credit for the idea. Another mud member & vendor @ToyotaMatt mentioned using a stud in place of a bolt. I just stumbled across a proper length stud.

They were out.

Did the FJParts gasket end up being 3mm thick?

@ToyotaMatt you got a part number for the nut that would go on the studs for the thermostat housing?

 

[S.CarolinaFZJ80]

Here it is in action.

 

[jestlurnin]

This is awesome. Thank you @ToyotaMatt for the part # @S.CarolinaFZJ80 for the images!

 

[DenverMike]

Since it has been nine years since a thread has been created discussing the installation of a thermostat on a 2F engine, and since I spent about 30 minutes yesterday trying to figure out how to do the installation correctly with the odd gaskets that are included in different rebuild kits, I thought I would quickly show the steps that one would take to properly (hopefully) install the thermostat. (Also the old thread has lost its picture links)

EDIT 8/12/19: Cool Cruisers and SOR have gaskets (upper, lower - thick and thin) readily available. Search on their sites for "thermostat gasket". Not sure (it's been a while) but there may be OEM parts available as well. Search on your favorite Toyota parts website).

1. On a cool engine, locate the thermostat. It is on the front on the straight 6 engine (F thru 3FE). In the photos below it is circled in yellow.

View attachment 1479621 View attachment 1479622


Place a bucket or pan underneath and loosen the hose clamps. Allow the coolant to drain into the bucket.

2. Remove the top half of the thermostat housing by removing the two bolts. Remove them slowly and carefully as these have a high tendency to break within the aluminum housing. They are fairly thin and long, and bind up in the aluminum due to the increased exposure to water.

View attachment 1479628

3. Remove the old thermostat from the housing if you are going to replace it with a new one. If you are not then you should test the thermostat to make sure it still works by placing it in a pot of water and monitoring the temperature until it reaches the proper expansion temperature. At that time the thermostat should expand.

4. Remove the old gasket. Clean the lower and upper mating surfaces of any residue from the old gasket. Use a razor blade to scrape for material from the face of the thermostat housing, and then use a cleaning agent like general spirits, brake cleaner, or other non-residue creating cleaner to remove the oil from the surface.

5. Insert the thermostat with the visible spring facing down and the domed part up. It should fit into the lip in the lower housing. Install the thermostat so the "jiggle valve", as the FSM describes it, is located at the 11 to 1 o'clock position in the housing. It allows a little circulation until the thermostat opens. (NOTE: the thermostat pictured below does NOT have a jiggle valve).

This is the bottom:

View attachment 1479629



This is the top:
View attachment 1479630

Thanks for the great write up. I just replaced my thermostat but it hasn’t change the status. What temps are you seeing at the housing? I can’t tell if my reader/sender is bad or if my coolant is too hot. 205 at the thermostat housing, about the same at the top of the radiator then 135 exiting the radiator. Normal? Or too hot?

 

[73FJ40]

Thanks for the great write up. I just replaced my thermostat but it hasn’t change the status. What temps are you seeing at the housing? I can’t tell if my reader/sender is bad or if my coolant is too hot. 205 at the thermostat housing, about the same at the top of the radiator then 135 exiting the radiator. Normal? Or too hot?

Did you use an OEM thermostat? What was the temp rating?

 

[DenverMike]

I was asleep at the wheel when I ordered from Cruiser Corps: it’s an aftermarket 185

 

[ToyotaMatt]

Please subscribe to my new T-TEN Empowerment through Education Technical Channel if you like what you see and hear

thanks

NOTE : produced with the help and technical consultation of @S.CarolinaFZJ80

 

[donrolla]

I was thinking about replacing my thermostat on a 1978 FJ40 because it is so old but after reading this thread, I am hesitant to tear into if for fear of breaking bolts and gasket issues. Can I use the four bolt system available for 1980+ models without any issues? Does it make sense to install the 4 bolt kit rather than trying to deal with the current 2 bolt system? Did anyone ever figure out what the 12 o'clock reference was to? front of engine to back or back to front?

 

[ToyotaMatt]

I was thinking about replacing my thermostat on a 1978 FJ40 because it is so old but after reading this thread, I am hesitant to tear into if for fear of breaking bolts and gasket issues. Can I use the four bolt system available for 1980+ models without any issues? Does it make sense to install the 4 bolt kit rather than trying to deal with the current 2 bolt system? Did anyone ever figure out what the 12 o'clock reference was to? front of engine to back or back to front?

not replacing your so very old older the old 1978 Thermostat becasue of fear of breaking one or more of the same old crappy and weak Simple Simon is a old wise tail appoach that is kicking the JDM can of TEq down the road of it only will and does get worse each and every full rotation of the sun and moon ,

how do you know at all in any way shape or fit form and funtion , that the Dooms-Day scenero your talk about above is your pre-planned fate ?

- first use a nice deep CHROME thin wall 6-point 3/8" drive socket , sporting a 8-10" extension and a LONG handle flex head wrachet


- give each bolt a careful Sneak-Attack Righty-Tighty tweek to the Righty ,, ,,,,clock wise , then more so Lefty Loosy counter clock wise

repeat the above several times in a back and forth pattern , on the two 12mm hex clam shell bolts , DO NOT start on one thinking , about NOT-THINKING here is important , always use and apply the toyota Star-Pattern in and out FSM step by steps here ...


- if one or both will not budge and only THEN think Dooms Day is here , in a 12mm HEX Bolts way ?


- use the YELLOW only MAP gas torch kit via HOME DEPOT to pin point precision , get that Hex Head BOLT puppy cherry red HOT fast as u possibly CAN quicky like quik so the thermal BTUs do not transmit from the lower 12MM hex bolts threads into the Aluminum lower housing , keep that heat transfer to a minimum is requiired here


- the ONLY way actual way is H55F fast on the heat to cherry red status


- those bolts will back out now , then you seperate the Clam shells usinfg KIT GLOVES and a nice Rubber Mallet , a sand Filled one is best for me , that is called a DEAD BLOW hammer or mallet ...


- what is this GASKETS topic all about above your onerned about , please elaborate on that ?


matt

 

[ToyotaMatt]

I was thinking about replacing my thermostat on a 1978 FJ40 because it is so old but after reading this thread, I am hesitant to tear into if for fear of breaking bolts and gasket issues. Can I use the four bolt system available for 1980+ models without any issues? Does it make sense to install the 4 bolt kit rather than trying to deal with the current 2 bolt system? Did anyone ever figure out what the 12 o'clock reference was to? front of engine to back or back to front?

TOYOTA OEM thermostats no longer require a CLOCKING index because the "jiggle valve", as the FSM describes it,.//

is no longer on any of them have not seen that except on a FATORY PLANT A11 original era one ? that is to say if you ever see one on a so CALLED new oem 90916- of any sort ? walk the h#ll away from it and never look back ....

- i see the gaskets topic you refer to also , that is a EXRTEME case no doubt , but that final Solution using that K-MART Grade silly rubber thingy , is NOT THE WAY in any way correct ...

- the ONLY WAY on that , is to CLONE a Machine Shop milling and re-surfacing your cylinder head to engine block deck

- i WILL post some of my archived pictures tell 1001 words , TECH photos below on that , indeed chatty-matty topic , it;s too early on fathers day for all that .,...


stand by :

 

[clrussell]

Saving this info

 

[Nolacajun75]

Hello.
Hope someone can help me!!!

I have a 81 fj43 2f. It started overheating and driving me Crazy.

I replaced the following new.
Cruiser Corps aluminum radiator
OEM 190 t stat
New radiator hoses
Oem water pump
Sending unit
Burped level and incline using burp funnel, drove repeated several times,, removed temp sending unit once cool and topped off, burped again. Flushed with water and ran in between flushes 8 times. Clear full water flowed out of block drain.

Upper and lower gaskets are sitting correctly on the thermostat.

Still, It quickly gets max hot but not instant, as per the stock OEM gauge it also smells like it's getting really hot. Feels like it's getting super hot. The top of the radiator is super hot and the top radio to hose is really hard to squeeze. The bottom of the radiator is pretty cool and not as hard as the top hose at all.

Since this, I next got a 180 aftermarket thermostat. I removed OEM 190 thermostat placed it and the new 180 t stat in boiling water, both opened. Installed new 180 t stat after flushing again several times spraying hose into front of block, into sending unit, sprayed into drain, and flushed radiator, drained and flowed out great everywhere.

Will fill again and start to see what happens. Hope for the best. Just don't get it. I used 50 /50 red antifreeze with water wetter This time I'm using 70 /30 green with water wetter. It is driven fine and not overheated with the 50/50, red etc. For the past 2 years. This problem just came up.

Ordered laser thermometer. Will check different locations and post that soon as I can. I will also ground the wire to the sending unit to verify a grounds and goes to full hot.

Thank you all so much for your help and patience. I did read through every single post on this forum that I could find including this one more than once. I feel like I'm chasing a ghost

 

[1911]

Hello.
Hope someone can help me!!!

I have a 81 fj43 2f. It started overheating and driving me Crazy.

I replaced the following new.
Cruiser Corps aluminum radiator
OEM 190 t stat
New radiator hoses
Oem water pump
Sending unit
Burped level and incline using burp funnel, drove repeated several times,, removed temp sending unit once cool and topped off, burped again. Flushed with water and ran in between flushes 8 times. Clear full water flowed out of block drain.

Upper and lower gaskets are sitting correctly on the thermostat.

Still, It quickly gets max hot but not instant, as per the stock OEM gauge it also smells like it's getting really hot. Feels like it's getting super hot. The top of the radiator is super hot and the top radio to hose is really hard to squeeze. The bottom of the radiator is pretty cool and not as hard as the top hose at all.

Since this, I next got a 180 aftermarket thermostat. I removed OEM 190 thermostat placed it and the new 180 t stat in boiling water, both opened. Installed new 180 t stat after flushing again several times spraying hose into front of block, into sending unit, sprayed into drain, and flushed radiator, drained and flowed out great everywhere.

Will fill again and start to see what happens. Hope for the best. Just don't get it. I used 50 /50 red antifreeze with water wetter This time I'm using 70 /30 green with water wetter. It is driven fine and not overheated with the 50/50, red etc. For the past 2 years. This problem just came up.

Ordered laser thermometer. Will check different locations and post that soon as I can. I will also ground the wire to the sending unit to verify a grounds and goes to full hot.

Thank you all so much for your help and patience. I did read through every single post on this forum that I could find including this one more than once. I feel like I'm chasing a ghost

That is pretty thorough!

I only have one more thing to check - your distributor advance mechanism, and the ignition timing in general. Retarded timing will produce extra heat. I have seen badly-retarded engines that would heat headers to cherry red, and still run semi-ok. When I first got my own (12/79, 1980 model) 40, it was running hot on the highway until I found that the vacuum advance mechanism had rusted and was inoperable. Replacing the distributor with a rebuilt unit fixed it. I was also able to advance my base timing a bit since I am de-smogged.

 

[John McVicker]

You’ve done a good job of trying to fix your problem. I would suggest checking your temps with an infrared temp gun. I know you said you replaced your Sender…but you may be chasing a ghost. Infrared to be certain.

 

[Nolacajun75]

That is pretty thorough!

I only have one more thing to check - your distributor advance mechanism, and the ignition timing in general. Retarded timing will produce extra heat. I have seen badly-retarded engines that would heat headers to cherry red, and still run semi-ok. When I first got my own (12/79, 1980 model) 40, it was running hot on the highway until I found that the vacuum advance mechanism had rusted and was inoperable. Replacing the distributor with a rebuilt unit fixed it. I was also able to advance my base timing a bit since I am de-smogged.

Thank you. The vehicle is desmogged. Don't think it ever came with smogged anything as it came from South America. Advanced vacuum going through the distributor is a brand new piece and I didn't touch anything with the distributor after I changed it out a year ago with all new parts and it's been running beautiful ever since. So I don't think it's anything with the timing because right before this started it overheating for the last year I had no issues and didn't change anything.

Thoughts, I'm at a loss

 

[1911]

Thank you. The vehicle is desmogged. Don't think it ever came with smogged anything as it came from South America. Advanced vacuum going through the distributor is a brand new piece and I didn't touch anything with the distributor after I changed it out a year ago with all new parts and it's been running beautiful ever since. So I don't think it's anything with the timing because right before this started it overheating for the last year I had no issues and didn't change anything.

Thoughts, I'm at a loss

I would still take the distributor cap and rotor off and see what the advancer mechanism looks like; possible it could have rusted during the past year, especially if not vented well. U.S. market late 40's have a vacuum venting system for the dissy that keeps ozone and excess moisture out.

 

[Nolacajun75]

You’ve done a good job of trying to fix your problem. I would suggest checking your temps with an infrared temp gun. I know you said you replaced your Sender…but you may be chasing a ghost. Infrared to be certain.

Hey John, yes I Just got my laser thermometer. I will check the temps in these locations and post what I find once I get it done. Going to fill it with straight distilled water just to flush out the hose tap water and check everything before I drain again and refill with 70 /30 green fluids again for the 30th time LOL. The way I do not have a heater installed so there's no heater lines to mess with in case someone ask.