jacksonpt

as a follow-up...

I payed particular attention to the heat this morning on the way to work (7 degrees F at my house this morning). My truck was in the garage over night, so I had that going for me. I have the V6 with an auto tranny, for comparison's sake, and a TRD tranny cooler.

It took about 3-4 minutes for my temp guage to be at normal operate temp - just below middle on the guage. I turned my heat on then and it was warm. Not sure if I'd call it hot or not, as that's a relative term, but it was definitely warm... warm enough to make my freezing cold fingers burn a little. Took about 10 minutes to get the cabin to where I didn't feel like I needed the heat on anymore. As an FYI, I generally like it cooler than most people, so the 10 minute thing might be a bit misleading.

Hope that helps.

Hugo

Jamie, I live in Québec City. The heat is ok, althought the rightmost vent always shoots colder air (compared to the other ones).

I often use the recirculating air position + the AC (to prevent fogging) to get a little more heat; I also make it a habit of turning on the rear heater to make the heat more uniform. If you do that + recirc. the aire, it gets warmer.

02SE

That's a characteristic of a thermostat, that is stuck open.

It's easy to change too.

GSGALLANT

The thermostat is easy enough to test. Take it out, put it in a pot of water, and heat up the water while checking the temperature with a thermometer. Get the specs for the thermostat opening / closing temperatures for your truck, and see how they compare to the test.

Toms2runner

I think it is a thermostat problem as well, but check your coolant first. If you coolant is low it could cause problems too. If it hasn't been changed in a long time it could gum up in the heater core. I fixed one on my 71 Riviera by unhooking the heater hoses and connecting the garden hose to the core. I was able to blow out the blockage. That worked for a couple years until it got really blocked. I haven't bothered fixing it because it doesn't get that cold around here.

Keep in mind that the last two positions on the dial for defrost also use the AC compressor. Your air conditoner is on when the defroster is on. AC units remove humidity from the air and that is a big part of removing the moisture from the windows.

MTL_4runner

I did exactly what you mentioned (hook the garden hose up to both the heater core and the heat valve and made sure there was good flow through there......both seemed fine) when it was still warm because I was sure the issue was a blocked heater core. I even used the hose to backflow check the heater hoses coming from the engine (ie I hooked up the garder hose and watched for flow coming out the radiator hoses) and they flowed fine too. I am very meticulous about fluid levels (so no low coolant) and I just changed it (when I checked the system with the garden hose). None of which seemed to make a difference. I hope it is as simple as a bad thermostat because I am not tearing the dash apart or changing the water pump in the middle of winter. I got the thermostat this morning and will try to get it in tonight (can't wait, it's -10 here now!).

MTL_4runner

Keep the suggestions coming, I appreciate the help on this!

lv4runner

Had the same problem before with my 94 22re. It was a stuck thermostat that was stuck open. Took a long time for the engine to warm up and it always ran too cool. Replaced the thermostat and problem solved. My temp gauge seems to float just below the halfway point. If yours is lower like maybe a 1/4 of the way, I'd change the thermostat.


Good luck, let us know what happens.

MTL_4runner

The wierdest part of this is that the engine seems to heat up normally (for this time of year) and you get reasonable heat at low speeds (nothing to write home about but still warm) but it is when you go highway speeds that is really cools off (which is exactly the opposite of what I would expect). The needle for the temp is only just under the halfway so it seems ok in that respect (I need to watch if it is dropping on the highway, hence the drop in air temp).

Scofco

I have a canvas grill cover I cut to fit for when it gets below -20c.
Heat works like a hot damn though.
Every once in awhile I'll string a blanket from the roof to the floor behind the front seats so I don't have to waste heat on the rear half of the 4runner.

02SE

So, did the new T-stat fix the problem?.

MTL_4runner

Didn't get to do it yet....been on vacation and had to take the Civic.
I am hoping to do it this week and I will definatelty post the result.

CynicX

also sounds to me like a stuck thermostat not throttling the proper coolant temp.

I doubt its the tranny cooler since I've had my truck in the single digit temps with no affect on the heat n I have a tranny cooler....

keep us updated....

dallison

heat is extremely warm

MTL_4runner

OK.....update.

I finally had a nice day in the middle of winter to see if installing a new thermostat would help the issue. Easy to change and I had to drop the skid plate to do it. I took it out for a spin and tried out the heat. Again it was warm but not what I would consider hot at all. So I am beginning to get a little frustrated with this mystery problem so I decided to do a little check on all the heater hoses to see what the deal is. The top radiator hose heats up nicely and seems to build decent pressure in there. The heater hoses going to the heater core also seem to be heating up quite well. Then I felt the bottom radiator hose and it was cool to the touch (not cold, just cool). Now to me this was not normal and seemed like a thermostat that wasn't working (but remember I just put in a new one). So a shut the engine off and felt the fins on the radiator.....there were definate sections of hot and cool (it was really hot on the sides, not as much in the center). So to me it seems like the radiator may be blocked (which sucks because I am sure these are crazy $$$$ from the dealer). So I am thinking that I will go ahead and do this to see if I can cure the vehicle of this issue.

Any thoughts? Anyone have something like this happen on their 3rd gen?
I am also baffled why this would not cause the vehicle to be overheating?
Any idea what I am looking at for an OEM radiator from the stealer?

Also if anyone knows a good source of OEM parts online in Canada, please post it!!!

surf4runner

mine gets HOT within 3 miles of driving.
i read another post here about a blocked bypass/passge line regarding transmission shifting. maybe another place to check if limited coolant is going through the heater core.

02SE

Are you sure there is no air trapped in the system?.

If the radiator is blocked, it would cause the coolant temperature to be hotter than normal.

Is the fan clutch operating as it should?. If it locks up, it would draw too much air through the radiator, potentially overcooling the engine.

MTL_4runner

I am positive there is no air trapped in the system.

The fan is working fine as far as I can tell (will double check).

I am guessing it is one of three things:
1) Radiator is blocked
2) Water pump is not working
3) Blockage in the engine block (not likely since I ran a garden hose through to check before).

The radiator seems strange the way there were very defined hot and cool areas, but I would expect the fins to all be warm on a radiator working well (hottest at the top yet warm at the bottom). My hunch is that something is just not right there, but I don't have another 4runner to do a side by side comparison on.

snap-on

on my truck even on a 0 deg morning (we had back in first part of dec) I could start her up, have it idle for a couple of min while i cleaned windows off, and by the time i hit the interstate a mile away and about 3min i can have about 1/4 on the gauge and 1/2 on the gauge with in a few min of that. 5 min latter your taking jackets off or swetting your balls off one of the 2. (again this is with single digits outside)

Amir904

sounds to me like u have a bad thermostat. on the highway is the temp needle at normal range or is it running cold?
edit: oops, didnt read all of the thread before posting, looks like u already tried changing the thermo.