FJ40 Thermostat Installation How To (1 Viewer)
- Thread starter Vae Victus
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This.
1 Upper Thermostat Housing 16333-60070
2 Lower Thermostat Housing 16331-60040
3 Bolt - Upper to Lower Housing 91611-B0845 (replaces 91611-40845)
4 Bolt - Lower Housing to Engine 91612-61025 (replaces 91611-41025)
5 Gasket - Upper to Lower Housing 16341-60020
6 Gasket - Lower Housing to Engine 16343-60011
7 Thermostat 90916-03014
8 Thermostat Gasket 90430-40058
Bear
SILVER Star
Thanks, Roger.
Yes, the Parts catalogue shows 16341-60020 as the sandwich gasket between the two halves of the 2-bolt thermostat housing.
That factory gasket is 1mm thick and made of typical gasket fiber.
My question remains: why do some gasket sets include a 3mm thick rubber gasket for this use?
This rubber gasket is NOT 16341-60020 unless there has been a revision from the factory in the thickness and the material it uses for this purpose.
Whether using the above-referenced upper and lower 2-bolt housings, or their variations allowing oil coolers, BVSVs, etc., the gap between the two halves is usually too large to be fit with a single 16341-60020 fiber gasket when also using the rubber gasket above the factory 180*F thermostat. The fiber gasket DOES fit correctly without that rubber gasket above the thermostat, and perhaps this is used in hot-climate areas not needing a cabin heater, or anyone deciding to not run a thermostat (not advised).
This also remains true if substituting the factory 190*F thermostat as in the 8/80 and up 2F engine. (It appears the 190*F thermostat was introduced to help keep emissions in line during the "spaghetti years," where Toyota continued to struggle meeting stricter emissions standards in the US, Australia, and Europe.)
So................who is making this rubber sandwich gasket, what is its purpose, why is it included in some gasket sets, and does it have an official part number? Is it a cheap aftermarket substitution? Or should we all use the single fiber gasket and crank-down on those bolts to stop leakage? Is that part of the reason so many bolts shear-off when being removed? Anyone?
Yes, the Parts catalogue shows 16341-60020 as the sandwich gasket between the two halves of the 2-bolt thermostat housing.
That factory gasket is 1mm thick and made of typical gasket fiber.
My question remains: why do some gasket sets include a 3mm thick rubber gasket for this use?
This rubber gasket is NOT 16341-60020 unless there has been a revision from the factory in the thickness and the material it uses for this purpose.
Whether using the above-referenced upper and lower 2-bolt housings, or their variations allowing oil coolers, BVSVs, etc., the gap between the two halves is usually too large to be fit with a single 16341-60020 fiber gasket when also using the rubber gasket above the factory 180*F thermostat. The fiber gasket DOES fit correctly without that rubber gasket above the thermostat, and perhaps this is used in hot-climate areas not needing a cabin heater, or anyone deciding to not run a thermostat (not advised).
This also remains true if substituting the factory 190*F thermostat as in the 8/80 and up 2F engine. (It appears the 190*F thermostat was introduced to help keep emissions in line during the "spaghetti years," where Toyota continued to struggle meeting stricter emissions standards in the US, Australia, and Europe.)
So................who is making this rubber sandwich gasket, what is its purpose, why is it included in some gasket sets, and does it have an official part number? Is it a cheap aftermarket substitution? Or should we all use the single fiber gasket and crank-down on those bolts to stop leakage? Is that part of the reason so many bolts shear-off when being removed? Anyone?
David70FJ40
Older Than Most
When I replaced the thermostat two years ago, I missed the circular gasket. A PO didn't replace it so since I didn't see it I didn't replace it either. Engine temps never got above 150, summer or winter, and the heater wasn't blowing out much heat either. I found an exploded drawing, ordered a new housing from Roger, while he still had them, made sure I had the proper gaskets and now I have a constant 180 degrees on the gauge and in winter the heater actually blows out hot air. Terrific instruction thread. I wish I had seen it when I was in the process of working with mine. Just goes to prove the wealth and depth of the knowledge here on MUD.
My thermostat cover housing (that top piece) has corrosion on it. My O-ring is missing. My bolts are cruddy. The stat itself is an unknown. So I ordered that kit from Racer. I'm replacing the whole schmear.
Are you saying the upper and lower thermostat housing won't fit together when you install the rubber gasket on the thermostat, as shown below? I've not personally experienced that problem. When you take out the original thermostat, the gasket should be there. It should go back the same way. Notice the middle part of the thermostat is raised, and the gaskets fits around it.
I've also not seen a 3 mm sandwich gasket. Which kit did you find it in? That sounds like a recipe for leaks. The purpose of the gasket is to seal between 2 metal surfaces rather than to fill a gap.
Bear
SILVER Star
Thanks, Roger. Yes, I agree.
I have tested the problem on 10 different housings I have sitting loose on he shelf.
If you refer back to the photos and discussion from the original poster, his Item 7 in his second post illustrates both the fiber sandwich gasket and the thicker rubber sandwich gasket. Then in his item 10 he proceeds to install the thick rubber sandwich gasket for his final installation, not the thinner fiber gasket.
I'm not sure where these thicker rubber sandwich gaskets originated(I have several) as well as the thick cork version of it (I also have). I see where other guys are indicating they also have some of these thicker gaskets that came in "kits" of gaskets they purchased. They may be aftermarket, or not; they may be incorrect for the application. Or, they could be correct in certain instances. Right or wrong, the OP appears to have used one, and since I, too, have noticed this discrepancy, I questioned the "experts" out there for opinions. I don't think the solution to sealing the gap should include excessive amounts of RTV as some have done in the past.
The torque on the attaching bolts may be different if this thicker gasket is used rather than the thinner fiber gasket. Additionally, the problem may go away if when tightening the complete assembly, the upper rubber gasket atop the thermostat is compressed sufficiently to allow the assembly to seal the halves using only the fiber gasket. Hopefully doing so doesn't put undue pressure on the thermostat itself.
Perhaps the question I should have asked is: how many folks out there are using a rubber gasket between the two halves of the thermostat housing, and where did you buy it?
I have tested the problem on 10 different housings I have sitting loose on he shelf.
If you refer back to the photos and discussion from the original poster, his Item 7 in his second post illustrates both the fiber sandwich gasket and the thicker rubber sandwich gasket. Then in his item 10 he proceeds to install the thick rubber sandwich gasket for his final installation, not the thinner fiber gasket.
I'm not sure where these thicker rubber sandwich gaskets originated(I have several) as well as the thick cork version of it (I also have). I see where other guys are indicating they also have some of these thicker gaskets that came in "kits" of gaskets they purchased. They may be aftermarket, or not; they may be incorrect for the application. Or, they could be correct in certain instances. Right or wrong, the OP appears to have used one, and since I, too, have noticed this discrepancy, I questioned the "experts" out there for opinions. I don't think the solution to sealing the gap should include excessive amounts of RTV as some have done in the past.
The torque on the attaching bolts may be different if this thicker gasket is used rather than the thinner fiber gasket. Additionally, the problem may go away if when tightening the complete assembly, the upper rubber gasket atop the thermostat is compressed sufficiently to allow the assembly to seal the halves using only the fiber gasket. Hopefully doing so doesn't put undue pressure on the thermostat itself.
Perhaps the question I should have asked is: how many folks out there are using a rubber gasket between the two halves of the thermostat housing, and where did you buy it?
For some reason I had both gaskets in my gasket set. I dont recall where the gaskets came from. I do remember trying to decide which one to use. They both seemed to work, as i swapped thermostats a couple of times. I think I ended up with the fiber gasket, but I still have the thick rubber one.
Vae Victus
Posting more than I know
- Thread starter
- #31
WRT the halves not fitting together - with the round rubber grommet on top of the tstat the two halves did not fit together leaving a 2 mm gap between. Without that grommet it fit together easily. (See one of the photos above)
I decided to try the thicker gasket instead of forcing the halves together.
IIRC it sounded like the metal of the tstat was hitting the top housing - but that doesn't make sense does it?
I'll pull things back apart and report back facts instead of vague memories.
I decided to try the thicker gasket instead of forcing the halves together.
IIRC it sounded like the metal of the tstat was hitting the top housing - but that doesn't make sense does it?
I'll pull things back apart and report back facts instead of vague memories.
S4Cruiser
SILVER Star
I ordered oem parts through one of our mud vendors and the Toyota gasket I got to fit b/w the two halves is the fiber one. What's the Toyota part number for the thicker one? I'd rather not purchase a 'kit' just to get the thicker gasket.
@Bear - this goes back to your original question - what is the specific Toyota part number for the thicker rubber (or cork) gasket?
@Bear - this goes back to your original question - what is the specific Toyota part number for the thicker rubber (or cork) gasket?
John McVicker
SILVER Star
This is a great thread. Subscribed.
Agreed. Seems like a simple thing to do, but I messed mine up so will now get it corrected.
I'm following this now... I want to see this 3mm rubber gasket mystery solved!
Vae Victus
Posting more than I know
- Thread starter
- #36
Me too. I ordered the gaskets so long ago and ordered things from so many sources I have no idea if the rubber gasket was in the FelPro kit or something else.
I'll see if FelPro lists the parts in gasket kit
EDIT: They do include both in their engine rebuild kit.
I'll see if FelPro lists the parts in gasket kit
EDIT: They do include both in their engine rebuild kit.
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Bear
SILVER Star
Thanks for checking, Vae. Were there any written instructions with that kit that might explain when either gasket is to be used?
At least it's not a replacement decided upon by a third-world company.
Any idea where the cork version of that gasket originates?
The plot thickens.
At least it's not a replacement decided upon by a third-world company.
Any idea where the cork version of that gasket originates?
The plot thickens.
Vae Victus
Posting more than I know
- Thread starter
- #38
Instructions? Ha. Nope, just a box of funny looking rubber, cork, paper, and metal gaskets.
Haven't seen a cork version of that gasket yet, but I'll bet it works better than the thick rubber one as it squishes out too easily.
S4Cruiser
SILVER Star
Found this photo online of the cork version. Looks like a SOR part.
I had not replaced my thermostat before my engine rebuild. I figured it was fine and reinstalled it, bad idea, it created a lot more work by having to empty the coolant. Here are a few pictures during the replacement. I purchased both my new thermostat and center gasket through Napa. The gasket that goes on top of the thermostat comes with the thermostat it self. The rubber center gasket did not fit as well as expect so we ordered a OEM one. The OEM one is a thin paper gasket which is what we ended up using. Of course the bolts snapped off so we had to drill and easy out, PIA. I am replacing them with some SST bolts and using anti-seize.
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