vikkz

i hope you figure this out i got the pdf fsm for you year truck somewhere on my computer if you need it might help with diagnostics of the heater.

j2the-e

If your lower hose never gets hot, the tstat is not opening. If the tstat isn't opening, there's no way to get all the air out of the system. Water should flow into the heater core when the tstat is closed, but not if there's an air pocket. I would run it at 1500-2500 rpm with the funnel attached and a blanket over the grille to block the airflow and allow it to heat up faster. Do this until the tstat opens and the lower hose heats up.

jerry507

You said your lower hose temp was 50F IIRC, what is the ambient temp?

cheez

It doesn't sound like the stat to me. I just had 2 bad thermostats in a row and the symptoms definitely included overheating. If the coolant in the block is not circulating it will heat up VERY quickly when driving and the heat (if there is good circulation to the core) will be scalding hot. this really seems like the coolant is not flowing to the core and nothing more than that. At this point, I'd do a block test just to make sure you dont spend too much money chasing something around. The HGs can fail in funny ways and let exhaust gasses into the cooling system causing "air bubble" like symptoms. just my .02.

JonnyBoy

You have a 195* thermostat and you measured 180* at the thermostat housing...then 50* at the lower hose? And you think the thermostat is opening? I hardly ever used the heat on my pickup that had the 22r, but when I did it was never overly effective other than it was warm enough to defrost the window. I pretty much attributed it to my radiator being more efficient and larger than the original design, but I drove it more in the summer when it's ridiculously hot here, so I just dealt with it. Do you have a small enough radiator?

iliketoyota

i just kind of assumed it was opening because it was after driving it for about half an hour and it never overheated. And yes it is the factory size radiator.

I think that since most heating systems work the same in cars, there is no reason it shouldnt be able to get to at least 165f like my dads 1996 camry with 212,000 on the original heater core. Its barley 100 now and gets to 120 or so on recirculate after driving it for half an hour or so when the air its heating is already partially heated.

iliketoyota

so you think that maybe when im bleeding the system its not warming up enough just sitting there to open the tstat? I usually do run it up to 2500rpms but the lower radiator hose never gets very warm at all. I usually just keep squeezing the upper rad hose and the heater hoses till it quits taking coolant after about 15 minutes.

iliketoyota

just put a new head on it a few months ago after on of the hoses going to the TB split and i lost all coolant. So everything should be good there. It has been 6000 miles and i havent had to add a drop of coolant. Oil is good too.

JonnyBoy

Now that I think about it for half a second, I'd bet your thermostat is opening. I temporarily forgot that the 22r thermostat is in the upper hose, not the lower like the v6's. Humor me on this one, get ahold of some cardboard and cut it such that it blocks the lower 1/3 to probably 1/2 of the radiator at the most and stays in place. Let it idle and watch the temps, probably with your laser. If it doesn't seem to get much warmer idling, try a little drive. Let us know if that makes a difference a your heat vents.

iliketoyota

well first of all im an idiot....second i got it fixed. i went to put a new thermostat in it again today and when i took the housing off...i realized the old one was put in backwards. Put it in the correct way and i have good heat. Im glad its fixed but damn i could have had this fixed in 10 minutes instead of taking the whole dash apart and ordering 3 different heater cores trying to find the right one. Oh well, at least now i know ill never put a thermostat in backwards again.

rworegon

Good. So what temp is the duct kicking out now?

I will refrain from making any comment on the t-stat being reversed.

cheez

I hear ya brother, I've done that too. I'm glad the issue is fixed though, enjoy the heat!

jerry507

So I have always been under the assumption that the tstat doesn't fit in backwards. But also I've rarely seen a description about what "correct" actually is. According to the FSM picture, the "slug" points down into the engine on the 22RE and the pointed dome/curvy part faces up into the outlet.

That's correct right? Otherwise I'm gonna feel really stupid haha.

seabee 86

When u replace your t-stat take a picture of the old one to reference off of.

vikkz

its good that you fixed it lol took 2 pages of posts to get it. I did that to my first car ever was still trying to learn the basic stuff on cars at the time and i put it backwards but mine was overheating because of it. Have fun with the heat now.

iliketoyota

well the heat is much better than before, but still not great. I have read from multiple people on here that it should be blowing about 165 and mine still never gets about 135. I know im being picky but it takes alot of heat to heat the whole cabin of a 4runner.

The heater hoses are both about 140 right at the firewall. It just seems like either the water looses 50 degrees from the pump to the firewall. Even though its only 20 degrees out i should be getting hotter heat than this. Im usually already where im going before it gets warm in there.

The camry has no problem blowing 160-170 degree heat in this weather with 240,000 miles. So there is really no reason mine shouldnt. I have taken the water pump off and it checked out good, no broken fins and the propeller isnt spinning on the shaft. It looked almost new. If anyone has any suggestions that would be great. The thermostat housing gets to 190 degrees so i think the thermostat is fine even though the lower radiator hose is cold. Ive already put 4 in it, tried a few different brands, not a toyota one yet though. Although since the thermostat housing is up to temp i would assume its fine.

j2the-e

Still sounds like a possible air pocket in the heater core. It needs to be run with the cap off and a funnel attached until the tstat opens up(lower hose warm). It can take forever when its cold out. Or use an air lift tool.

iliketoyota

I wouldn't think so but possibly...I'll. Try it with that no spill funnel now that the thermostat is in there right now.

jerry507

Your problem can't be in the heater core. If you're getting only 140F at the heater goes going to the heater core, you'll never get anything higher than 140F. However, you say it's 140F at BOTH heater hoses, which shouldn't be possible. That would mean you're not dissipating any heat in the core at all.

I would be somewhat skeptical about your measurements. Getting a good IR (I assume you're using a IR thermometer here) measurement off the thermostat housing is not that bad. The whole housing will be the right temp. If you've got subpar flow, that heater hose (being an insulator) will be different temperatures all around the hose. It would be far more accurate to pull the hoses at the firewall, feed them into a bucket and measure the coolant temp in the bucket.

You've also got another related issue; you don't get up to temp quickly. Your thermostat seems to be working at the right temp, maintaining regulation, but exactly how long does it take you to get up to 190F? I assume your dash gauge reads middle? Try and give us some concrete numbers like how long at idle, or how many miles of regular city or rural driving.