Low Heat from Vents

[Canuckrz]

I'm getting little to no heat in the cabin. Heres a list of things I've done and checked:


-I just replaced the water pump along with the timing belt and other odds and ends. Also I just finished doing a coolant flush running cleaner and water through it for 4 hours. The low heat problem was still around beforehand.

-The cable running to the coolant valve on the firewall is busted but I put the valve in the open position and it feels to be moving when I shift the valve though I will double check it and pop the hose off.

-Both heater hoses are equally as hot as the main coolant hoses. which leads me to believe that the coolant is getting through the core which also means the valve is open.

-The engine temps via OBD2 are a solid 90-92C. And there have been no other symptoms besides the low cabin heat.

-The door that opens and closes under the dash to let air in gives a very audible chumph noise when opening and closing so I'm fairly confident in saying that its still connected.

-One thing I noticed is when on defog the side vents seem to get more heat than the windshield vents.


I'm running out of ideas here as to what the problem could be. Any shots in the dark are welcome at this point.

 

[Canuckrz]

Confirmed the coolant valve opens and closes properly.

The flush knocked out a fair bit of crap but it apprears to be mostly just small rust particles from the coolant passages.

Blew air and coolant through the heater core and it seems to be flowing sufficiently but not enough to rule out a partial clog.

Also theres something odd I noticed under the dash with the cables going to the vent box. On this 3 armed lever only 2 points are being used, nothing else in the area looks like it could hook to it. Possibly for the optional rear heater that I don't have?

Also theres another small lever of some sort that is zip tied in place and doesnt appear to have anything to hook to it and its purpose is unknown. Attatched is the picture.

 

[Canuckrz]

I found this picture in the heater core removal thread. There seems to be a rod that connects to that small lever that someone zip tied. I cant see clearly where the rod runs to however, perhaps the 3rd arm on that lever?

Does anyone know the purpose of the rod/arm?

 

[IBallEngineer]

Bump, cuz I is curious.

 

[Canuckrz]

The pivot that was zip tied was the door for the windsheild vents which explains the low flow to them but however does not solve the heat problem. It looks like the rod is connected to the 3rd arm on that other pivot. I'll likely bend one out of 3/32 welding rod since I cannot find it in the EPC atm and I have to leave to drive back across the country in a couple days.

I've put about 20L of water through the system after removing the flush treatment and water. The water is still coming out somewhat murky with small sediment similar to swamp water. I'm going to keep running water through it until it comes out clear. Then it will be refilled with toyota red and distilled water.

No noticeable effect has been had on the heat problem so far even after the flush.

 

[Canuckrz]

Water finally became largely clear after around 35L. The product I used for the flush was prestone super radiator cleaner. It sure ripped off one hell of alot of sediment and guck out of the system though its unclear if it actually helped my issue at this point. Its nice to know that I will now have pure clean toyota red running through a clean system however. It seems to be a bit warmer but not anywhere near where it should be.


I made the connector rod, however one thing struck me as odd which was I had to bend the rod in the middle so that it wouldn't interfere with another one of the 3 arms, and from the picture the rod appears to be straight.

I've "aquired" an EPC and I'm going to see if I can find a proper breakdown of the arms cables and rods.

 

[Canuckrz]

The EPC I found is unfortunately terribly outdated and is just a part number lookup but lacks any of the actual cateloging functions of the newer EPC's with diagrams etc.

I've also removed the blower motor and confirmed that both doors for the inside/outside air are functioning properly.

I've been searching and I cannot find a picture/diagram of the layout of the cables/pivots/shafts in that area for the cooling system or any better pictures. As far as I can see under my dash that arm is the only thing it can connect to but it just doesnt seem to jive with the other picture completely.

-The shaft appears to be straight and while going in the same area appears to have a slightly different trajectory.

-If you look at the 3rd arm in the back on mine it has a small shaft on the arm that something pivots off of vs a fairly large shaft almost as big as the width of the arm itself. Possibly another pivot that clips onto that arm.

Can someone please take a quick picture under their dash of where the rod goes to and how/where it attaches? I have to leave to drive back across Canada in a day or two and I would greatly prefer to have heat this time round.:help:

 

[Canuckrz]

Well I made it across the country again, apparently the heat seems to vary slightly here and again while driving according to the other buddy who was driving with me but I didn't notice it much myself. Other than that no change in the heat output after another 5k of driving with new pretty much everything in the cooling system.:dammit:

-I haven't ordered a new rod yet for the lever, however after messing with it in various positions it doesn't seem to make a difference. With the flap in its formerly zip tied position is seems to be getting slightly more heat to the vents.

-No signs of leaking coolant anywhere. There was a loose constant tension clamp going to the heater core that I replaced with a worm clamp but there was nothing other than that.

-Might be worth mentioning that the rad cap was f'd when I replaced it along with the water pump and everything else. Don't know if this is a sign of anything or was simply poor maintenance on the previous owners side.


Is there any way to test for a partially clogged heater core? Its getting enough flow to supply both lines no issue and both lines are equally hot as the rest of the system. Also with that cleaner I put through the system its hard to believe there could be anything left to gum things up after 35L of swamp like particle water.

 

[Grenvilleter]

I don't like the look of those zip-ty's. Def not stock.
You may need to stick your head under someone else 's runner to see whats missing.
It has to be obvious when you see a working system.

Where are you located currently?

 

[JBurt]

Do you get hot air out of your rear heater?

 

[Canuckrz]

I put in a home made rod out of a 3/32 welding rod however it didn't look quite right and I found I had slightly better heat with it zip tied so I put it back like that until I order a new rod from the dealership.

My 4runner is not equiped with the rear heater, its an american truck. I'm in Calgary AB.

Its also worthwhile to mention that outside air temps don't seem to have a ton of effect on vent temperature.

 

[Canuckrz]

My local pick and pull finally got a couple 3rd gens in so I could check out the levers and pivots.

There was a 2000 there with mint headlights that some jackass decided to screw up the lenses of with a lighter as he passed by. I really hate people sometimes. :rant:

But I digress, I hopefully found the source of the problem. The 3rd arm attached to the arm of another pivot I am missing. The missing pivot then connects to the rod which explains why it looked like it was going into left field.

I got both the rod and the pivot off the truck and snapped some pics for others to use for future reference. Heres hoping that the shaft for the pivot on my truck isnt missing/snapped off.....

 

[nevada]

I cant tell you for your specific application where the rods/arms need to be.
but the problem you're having is the blend door is open, or set to COLD inside the heater box.

you should be able to flip the levers around while the heater is on and feel the difference.

 

[Canuckrz]

Indeed. The issue is that pivot was entirely missing so I didn't know it was there to be able to mess with it. When its daylight again tomorrow I'm going to open the dash up again to see if its still hopefully intact and install the pivot and rod.

 

[ti-jean711]

Blend door problem

Hi back with a old post on my 1994 4runner looking to find with pivot move the blend door (witch one it is ) can find any pics of how my heater look like
the problem is I have tempered warm air on defrost ans cold on floor so I suppose the problem come from the blend door after flushing twice the core rad the water pass freelee wasn't rust or something else not shure if ther is a actuator to move that door ... is it ???
thanks for your help

 

[leonor700]

vents 4runner 1997 1996 1998 1999 2000 2001 2002

Hi anybody know if it is possible to find the square piece of the ac vents and what is the part number? it brakes with the years