Here's my problem: My 884runner 22re runs at normal temps, needle rises a bit on long steep highway grades. But when the temperature selector is pushed over to warm the engine temperature needle rises significantly, nearly into the red. Just as I am getting really concerned the fan kicks in and the needle drops down to normal. It continues this cycle whenever the temperature selector is in the warm position. When the selector is at cool the engine temp is completely normal. It only began doing this since my HG rebuild (5 months ago). Currently the radiator is leaking and could use a repair or replacement. My only thought is possibly air in the system due to the fluid loss from the leaky radiator causing the temp sensor to read the temperature of the air instead. Any ideas?? This is really bothering me. It's getting colder now in the morning and I would like to use the heater. Thanks in advance.

 

I've heard of the heater causing the (perceived?) temperature to rise before. I can't help you though.

 

Make sure you don't have any air in the cooling system.

 

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

The thermostat is closing on you, see the link above.

 

After finding a substancial leak in my radiator I ordered a new one from radaitorbarn, it should be here today. I figured it would be a good opportunity to upgrade to the heavy duty one. Anything I should know about putting a new radiator in? seems pretty straightfoward. Is the heavy duty one still a bolt in?

 

Radiators are easy. No worries. Unbolt, re-bolt, done. Good time to renew hoses...especially the little coolant bypass hoses that hover around the throttle body. If your 22RE is like mine, when you first start and run the engine after refilling the cooling system, it'll do a few weird things: idle rise, then fall by itself a few times; Temp rise unusually high until air is purged out of cooling system---it may help to rapidly squeeze the top radiator hose as it's warming up. Be sure to open(turn on) the heater valve when draining and refilling the coolant, and the during the initial warm up.
BTW, if by 'heavy duty' radiator you mean the one intended for the 6 cyl engine, the 3-row one, IMO it's not necessary. I had one for a few years and I found that when the outside air temp was high(heat wave, 95+ degrees, etc) and driving at highway speeds, that the 3-row rad cooled the 22RE less well than the 2-row standard one. Later I replaced the 3-row with a stock 2-row, and the temp never seems to vary, no matter how hot the air temp.

 

flush the system.

i had the same issue when i did a HG. ran a few weeks then overheated (from clogged rad) replaced and all was good.

 

it's the 'heavy duty' one for the 22re, according to radiatorbarn's website. Hopefully I can get it back together tonight.

 

just a side note-
if the engine is overheating with the heater on, it's likely because the coolant can flow more easily through the heater than the radiator, but since the heater core is not able to transfer as much heat as the radiator can, you will overheat. with the controls set to cold, the coolant is forced to flow through the radiator and it can, even when significantly plugged, pull more heat out than the heater core can.
since you're replacing the radiator, make sure you get the upgraded thermostat with the jiggle valve ( or two-stage) and flush it all well.

 

Definately spend the extra $5 and get a new thermostat from Toyota. Other brands aren't worth the $5 you save.

Read up on 4Crawler's site and consider getting the 2-step thermostat. Worked for me.

Cheers.

 

Purchased the OEM thermostat from Toyota.

I just finished installing the new radiator everything's hooked up and ready to roll. How can I get all the air out of the system? I've been pumping the top hose while the engine is warming up (with the heater on). Will that get all the air out? sorry for all the q's I'm still learning this stuff.

 

I've always left the thermostat and stuff off, then filled the radiator up till the thermostat housing is full... then I put the thermostat, the outlet and other stuff on over the thermostat then start the engine with the radiator cap removed.
... I start the engine and let things warm up then watch the radiator for coolant flowing through it...
then top the radiator up while the engine is running...
then add some coolant to the overflow reservoir.

it also helps if you can point the truck up-hill, where the radiator is higher than the engine.

 

I use a cv boot as a rubber 'funnel' in the rad neck.
I turn the heat lever to HOT and leave the heater fan OFF.
I put a piece of cardboard in front of the radiator so it warms up faster (like turning off the engine fan effect)
Overfill the rad using the rubber funnel. Idle engine until the gauge is in the middle, put the NEW rad cap on, and overfill the reservoir by 1" above the max line.

That's it. Double-check the coolant level the next morning (when cold) and top up if required.

 

Radiator's in and I believe the fluid is good to go. I took it out for a test drive on friday and shortly into the drive it started to overheat again. Same problem as before. So yesterday I did 4crawler's tip and drilled a small hole into my thermostat to allow the fluid to pass through. Gauge needle seems to run a bit high, but no more overheating.

 

Is this the 4Crawler page you looked at:
http://4crawler.com/4x4/CheapTricks/...tml#Thermostat

 

and what kind of drive was it? around town or on the highway?

 

yes...that's the one.

 

I live in a town about 4 square miles in size. I drove through town (2 stoplights) and hit a back road at 70mph. At that speed with the heat on it took about 5 minutes to get too hot.

 

so it tends to overheat at higher speeds...

at this point, I'd be leaning towards a radiator problem, plugged, or just too small, but you got a higher capacity one so...
are you using electric fan(s) or the stock fan?
is the fan shrouded properly?

... or maybe the lower radiator hose is getting sucked closed

 

I wouldn't necessarily say it's overheating at higher speeds, i think it just took that long for the engine to get warm(4 minutes after leaving my house I was cruising at 70.) I have the stock fan and the shroud is placed correctly, the lower hose is also new.

I will take it out for a longer highway drive soon and report the results.