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Attaching a pic here of my 3VZE in my 95 4Runner. As you can see by the staining, I am getting some coolant leakage from where the radiator hose enters the water pump area (at least thats what I think this is). I can definitely see the coolant seeping from the seam where the gasket is.
My inclination is to grab the gasket part #16341 on this diagram:
Is there anything else you would replace while doing this? Is the part labelled 16331A in this diagram the thermostat? It seems like it based on the image but I didnt think the thermostat was sitting in this housing. All of this is likely original so maybe I should just replace the hose and clamps as well? Not sure how far to take this, as I dont want to go too far as I do think a timing belt/water pump job is in my future (maybe next year)
Your engine is a 6 cylinder 3VZ-E type.
The parts diagram you show is for a 4 cylinder 22RE engine.
Your 6 cyl engine does not use the 16341 gasket, and your thermostat is not under that water outlet either.
You are gonna need some form-a-gasket material such as Toyota FIPG, or Permatex Ultra Gray.
Careful with the studs and nuts, they may be corroded and easy to break.
Last edited by millball; Sep 29, 2025 at 02:26 PM.
Your engine is a 6 cylinder 3VZ-E type.
The parts diagram you show is for a 4 cylinder 22RE engine.
Your 6 cyl engine does not use the 16341 gasket, and your thermostat is not under that water outlet either.
You are gonna need some form-a-gasket material such as Toyota FIPG, or Permatex Ultra Gray.
Careful with the studs and nuts, they may be corroded and easy to break.
Ok I knew something was up with that diagram because it didnt make sense for the thermostat to be there because I know where its actually located on the 3.0
Is it not possible to buy a new OEM gasket for that section? any idea where I can see a parts diagram for this section on my engine because I would like to pick up some replacement studs/nuts as well
The original sealant was a factory installed bead in a groove that exists in the lower part of the housing.
I'm not sure whether any replacement is offered for that, or not.
There is usually no paper or rubber gasket found there.
The original sealant was factory installed in a groove that exists in the lower part of the housing.
There is usually no paper or rubber gasket found there.
Ahh that makes sense. Thanks so much. Ill have to grab some sealant then. Honestly at this point I may just replace that entire upper part of the housing along with the hardware.
Just wondering... if my fan goes on immediately when the truck starts, is that a sign of a thermostat/temp sensor issue? Could it be the clutch? I feel like it never truly idles...
EDIT: I just read that it will actually never stop spinning even when the truck is not moving, but I should be able to stop it from spinning when the engine is cool and the clutch should be disengaged.
You should be able to tell when it’s cold and you drive it has a loud whooooooshing noise when engaged, when it isn’t engaged it will spin just not with the velocity and be quiet. Mine was whooshing in the middle of winter on cold starts is how I noticed my clutch went out.
I believe it engages by the fan itself hitting the pre set temperature to engage the clutch.
Last edited by Discombobulated; Sep 30, 2025 at 02:32 PM.
You should be able to tell when it’s cold and you drive it has a loud whooooooshing noise when engaged, when it isn’t engaged it will spin just not with the velocity and be quiet. Mine was whooshing in the middle of winter on cold starts is how I noticed my clutch went out.
I believe it engages by the fan itself hitting the pre set temperature to engage the clutch.
Right so I noticed that when I accelerate from a stop, it sounds like a jet engine 😁
I tried to test by seeing if i could stop the fan with a glove on a few min after a cold start, and theres no shot. So Im guessing the issue is the clutch fails but instead of failing so that the fan free spins, it just stays engaged permanently?
Honestly at this point if I am replacing the seal on the water outlet, and the fan clutch... Am I approaching new water pump territory in terms of dissasembly? And then in that case, timing belt? 😭😭
I wasnt planning on doing those major items this year but if I am going to be pulling it all apart maybe it makes sense. Alternatively I could just fix the leak and leave the fan alone... I assume worst case it bad gas mileage and fan wear.
The fan clutch is an easy job, I recommend getting an Aisin if possible, but how many miles on the belt?? That would be the deciding factor.
And yes most threads I have read states the fan just stays engaged instead of just not working, maybe they designed it that way cause it’s better to stay on than stay off but it does effect gas mileage and power for sure, also longer warm up times and running way cooler in the winter when normally it wouldn’t even run at all depending on the outside temp.
Good luck with whatever you decide but when my fan was on it was worse for me as with my 22re it’s already slow but you can tell the extra drag the fan puts on it
The fan clutch is an easy job, I recommend getting an Aisin if possible, but how many miles on the belt?? That would be the deciding factor.
And yes most threads I have read states the fan just stays engaged instead of just not working, maybe they designed it that way cause it’s better to stay on than stay off but it does effect gas mileage and power for sure, also longer warm up times and running way cooler in the winter when normally it wouldn’t even run at all depending on the outside temp.
Good luck with whatever you decide but when my fan was on it was worse for me as with my 22re it’s already slow but you can tell the extra drag the fan puts on it
So Im the 2nd owner, and the truck has 85k. I am 99.9% sure its the original belt. I spoke to the Toyota dealership that took care of the car since it was purchased in 95 and they had no record of doing the belt so the only way it would have been done is if they went to another local shop due to dealership shop prices.
The truck is definitely slow especially off the line but I expected that going in on the 3.0
If the clutch job isn't that intrusive maybe I'll just fix this leak and change the clutch and save the belt/pump for 2026
Sep 29, 2025 | 02:09 PM
but it does effect gas mileage and power for sure, also longer warm up times and running way cooler in the winter when normally it wouldn’t even run at all depending on the outside temp. 
