I have a 84 4runner, 22r. I have unsatisfactory heat and need some help. The 4runner has front and rear heat and neither blow very hot. I did some searching and thought it was the heater valve. It was stuck so I fixed it and I am still having issues. The truck does not seem to reach operating temp so I suspected the thermostat. I removed the housing and the coolant was steaming hot, much hotter than the coolant in the radiator. Could I have a plugged heater core?

 

Back flush it and see. How? Run water backwards through the heater core, that is shove a hose into the return line and open the inlet line.

 

I just did what 4 crawler suggested and low and behold I had a plugged heater core. I bought a new one at Kragen for 30 large and spent xmas morning switching it out. Now there is more heat than I know what to do with.

 

Does anyone have a pic of which is the return line and the inlet line?

I am going to try to flush the core. Only problem is its like -2 degrees so my outside hoses are not gonna work. The truck wont fit in the kitchen. LOL Maybe I can run a hose out the window?

 

http://www.4crawler.com/4x4/CheapTri...ne_Pix/14.html

 

the coolant hose's about 5/8" that feed from the engine block.. to the fire wall.. the a/c lines will be thicker and they will have a schreader valve on them so you will know not to mess with them at all (unless you want r12 or 134a in your face)

the heater core hoese should a hose clamp on the end of the hose..

 

Well, I am still freezing. I tested the thermostat with the stove to method and it is opening properly. I have hot coolant everywhere but the radiator. The coolant just does not seem to be circulating properly. All of the heater core lines had hot coolant. I am going to flush the heater core but I am worried. It is extremely cold here and I don't want any water to freeze inside.

 

blow all lines out with air compressor blow gun.

then add some coolant into the lines.. keep line up so, coolant wont drip out or hook them back up..

 

I flushed the heater core in both directions and it flowed freely, so I don't think that's the issue. It's just funny that the coolant is hot everywhere except the radiator. I can squeeze the upper and lower rad hose and there isn't any pressure. Could my radiator be plugged? What do you guys think about the small bottles of prestone flush stuff? I have a bottle that a buddy left in my garage. Maybe someone used stop leak in the radiator at some time and it plugged it up.

 

Sounds to me like a bad radiator. Try and flush it. And or get a new one. IF you heater core is good, hoses are good, thermostat good, then its prob your rad. Is there enough coolant in the engine?

 

I am pretty sure there is enough coolant. I will fill the rad to the top, run it with the cap off, and the coolant just sits there. No matter how much I drive, it does not seem to circulate.
Any opinions on the prestone radiator flush? What is the best way to use it? Should I just add it, drive a few miles, and flush the whole system?
I'll probably just buy a new radiator, but that will have to wait until payday.

 

I'd take the rad to a shop and have it flushed. If it still does not operate properly replace it.

 

i would drain all your coolant out and save as much as possible, just filter it out with some old scrap bed sheets and a bucket.. works very well..

i would spary the garden hose from the top hole to the bottom and see if you are getting a good flow of water coming out the bottom hole.

if its just trickeling you know you got a clogg

i would get a blow gun and try to use air compressor and try to use air pressure to to blow out the clogg..

by then i would say hell with it and start looking up prices for a new radaitor.. alot ppl on here say to use https://www.radiatorbarn.com/

i would check every parts stores price first and then see how much it would cost to fix the radaitor and then determine what would be the best route.

 

OK, so oddly enough the radiator flushed just fine. Just like everything else, it was not plugged up. This leaves me with one conclusion. Bad water pump, and now that I pay attention, the water pump does make a little noise on startup. Can't believe I didn't hear that before.

 

Is it a kind of grinding screeching noise? Then yea water pump is usually the last thing to look at.... its easy on a 22r to do.

 

to make the heater work on my 87 i had to park uphill and rev the motor to about 3 grand.... top the rad off and then cap it before letting it rev down.... sounds weird but it worked every time i had to drain the water i had to do this before the heater would work again... musta been a high spot in the coolant system in that truck....

 

well keep everyone informed of your progress.

 

Well, sorry it's been a while. I have some updates on the situation but don't have it completely solved yet.



As you can see I had some water pump issues. The impeller was obviously making contact with the timing cover. I suppose that would explain the lack of coolant circulation.
In this case one step forward is actually just a step to the side for a different angle on the problem.
After a new water pump I have hot coolant circulating. The rad, hoses, and engine are all hot. All of the heater hoses are hot as well. Now the funny thing is that the rear heat blows very hot as it should. However the front heat blows softly and is luke warm. If I move the heater temp control to cold the front heat is not hot but blows MUCH harder. The cable for the heater temp control seems to be moving properly but it doesn't sound like its moving the damper correctly. I guess that's the next thing I will check out.

 

you, got this.. you will get it figured out..

 

any luck with your heater prob my 87 4runner does same thing. rear heater is really hot front is warm at best when on recirculate.
i have a new water pump/ thermostat good engine temp just below half all the time