diesel power

Hi,

2001 4Runner

replaced the tstat tonight. after re-assembly i'm getting a tiny bit of coolant on the lower stud/nut of the housing. i used a new OEM tstat and new gasket. its not leaking where the tstat housing seals against the water pump. did i miss something?

also on my scangauge (its 40F outside now) it seems to run at 202*, lower rad hose cold to touch. i know stat is in right and vent hole is at the top. both heaters work.

i've replaced coolant before but never the tstat. it ran a little cooler before.

thoughts?

thanks in advance

TheDurk

Look underneath further back. Is it leaking where the water pump sits against the block? The three nuts/bolts that hold the thermostat also secure the WP. Maybe it was already leaking there or was about to and now you disturbed the original FIPG by doing the thermostat. I hope I'm wrong but its the only thing I can think of.

Oh, the jiggle valve is supposed to be downwards, but that won't cause a leak. Might help the cooling part. Don't over-torque, spec is only 14 ft-lbs. Over-torquing could also cause a leak in the back. Did you use a torque wrench? That FIPG is pretty brittle by now if original.

mt_goat

Its up for debate, down (6:00) helps with draining the block without removing the t-stat. Up 12:00 helps with removing trapped air while refilling, I prefer 12:00 myself. 2cents Of course once the t-stat opens its irrelevant.

diesel power

sounds like i should pull the stat out and check it? driving about 20 miles last night mostly flat peaked at 207* which previosuly would have been about 10* cooler. also i played with running the heathers and they do lower the water temp while they are on. once i shut them off it starts to climb again.

diesel power

sorry what is fipg?

and the leak appears to be coming from the stud where the nut threads onto it. i've blown it off with compressed air and it persists. the temp issue is more of a concern at this point. one of the studs came out when i pulled the tstat cover but it isnt the one i see the weeping from.


my biggest concern is the increased temp. have a 12 hour drive through mountains tomorrow and i'd like to get this figured out today. just want to make sure i havent missed anything obvious before i drain the coolant and pull the tstat again.

mt_goat

Form in place gasket (FIPG), sold at dealer or you can use certain RTVs. I always check a t-stat opening temp on the stove before installing.

My favorite RTV for coolant exposure:

diesel power

i'm guessing ultra black won't work? i'm getting ready to pull the stat and check but am thinking of pulling the water pump and re-sealing it if it isn't too hard. i still have one more new oem tstat.

is there any benefit to breaking off the nipple for the air bleed? i thought i read about that somewhere but can't remember for sure.

i do appreciate all the feedback.

btw is the water pump hard to get to one the coolant is drained and tstat out of the way?

mt_goat

Do you have a V6 engine? If so you have to remove the timing belt to remove the waterpump, PITA.

I don't know about ultra black for coolant, sorry.

I don't think the nipple hurts anything. They must put it in for a reason, I just don't know what it is LOL.

ChefYota4x4

iTrader: (5)

Mr. Goat is right! lol....

Did much research on this when looking into sealing up the coolant lines that hit the back of the t-cover on my 22re, as well as other fittings I had leaking. Soooo, when I tore it back down, I made DANG sure I found out either way. That, what Goat listed, is what i was told to use, even by Toyota, "If you're not gonna use Toyota FIPG". However, for oil/cam cover half moons, pan, t-cover..... Toyota FIPK all the way! lol. That stuff is INCREDIBLY good quality.

Napa's Coolant stuff is as good as you'll need. The black stuff is OK for Water, but NO WAY for anything near Gasoline.(intake gaskets, etc.)

ChefYota4x4

iTrader: (5)

PS> Howzit, Mr. Goat? 10,000 Posts+, ...DANG! You da man! lol.

mt_goat

Thanks, I hope I helped a few peeps along the way.

mt_goat

Diesel here's a thread you might want to look over, info on timing belt/water pump replacement near the end: https://www.yotatech.com/forums/f2/o...rature-199783/

blake.nemitz

sounds like you picked up too hot of a thermostat, ive bought one from toyota that wouldnt open till 220 when it was supposed to be 190 or something like that. and black silicon will work it works for me

diesel power

thanks for all the advice. yes its a V6

i tested the original OEM one i pulled out, the one i had just put in, and my other new spare and found this:

original one in car - opened slightly later (just barely), but took longer to close (vs the 2 new ones)

one i just put in last night plus the other new one- they perform the same as eachother. they seem to pop open a little faster and open further a little quick than the old one but they also close quicker. i'm guessing its because they are new.

they are all OEM 82*c tstats.

so now i'm perplexed about the temp difference. just driving home from my girlfriends house in town today i saw 206 which i never saw before...

mt_goat

Maybe you are getting air pockets in the cooling system. Leaks can make that worse too. Picture every drop of coolant coming out an air bubble goes in to replace it.

diesel power

well i ended up putting the second brand new tstat in and although it tested the same on the stove as the other one it seems to run a little cooler now. i captured all the old coolant minus a tiny bit and as far as i can tell i ended up putting more in this time. had both stat's weep hope at 12 o'clock but perhaps it had some air in it?

i'm gonna keep an eye on the bolt. it doesn't drip if i watch it but i do see a little coolant on it even after blowing it off with the compressor. truck has 134k on it. water pump was done at 92k along with the timing belt.

partly i think i'm used to my dmax running at 188-192. it stays there all the time unless i'm pulling my 40' trailer up a mountain.

thanks again for the advice guys!

TheDurk

For the record, the FSM (page C-12, V. II of my '99 edition) says jiggle valve down. I just do what Toyota suggests. I doubt it makes much difference.

J2F42C

When is the last time you have changed the water pump? Losing any coolant?

Here is a good read concerning operating temperature and the like:

https://www.yotatech.com/forums/f2/o...rature-199783/

diesel power

truck has 134k on it. water pump was done at 92k along with the timing belt. no it hasn't been losing any coolant.

J2F42C

Do you know if the timing belt tensioner was replaced at the same time?

I'd start to say to check the fan clutch, but since you see these temps all the time, not just idling in traffic, I'm inclined to believe it is not the clutch.