FaYgo

I got a used 97 4runner 3.4 V6 auto trans. earlier this year and have , since then, put about 9000 miles on it. a few weeks ago i was driving home from out of town ( like a 100 mile trip) and out of nowhere my heat guage shot up to red and coolant starts blowing out of the resivior all over the engine.

since that happened i have replaced all of the folloing things to try to fix the problem.
- radiator cap
- heat sensor
- upper and lower radiator hose
- thermostat
- water pump
- had the radiator washed and cleaned by a radiator shop
- and timing belt , but that is irrelevant i just did it when i changed the WP

It runs fine inner city driving and at low speeds. (1 - 55 mph)
yesterday i was going back out of town and i got 20 miles outside of town and it did the same thing, i can let it cool down and drive back at like 30 - 45 mph without overheating but when i get up to 70 - 80 it shoots coolant back into the resevior untill it overflows and the engine overheats.

i am affraid that it is the head gasket after searching the forums but if that were the case, it doesn't make sense to me how it could be fine all week long inner city driving ( to and fro work) and then all of the sudden go balistic when i get on the interstate.

and thoughts or ideas anyone has would be very useful.

replacing the head gasket is my last course of action, so i am trying to excersise every other possibility of what could be going wrong with the engine.

GrizzlyNC

I just had the same issue (on a NEW engine!) but it was HWY AND Climbing my road up to the house. It wound up being the Fan Clutch.. I went with a NAPA for 40.00 and it fixed it completely.. Just a thought.. But keep in mind it's a pain to get to..

DeathCougar

iTrader: (23)

lol its not a PAIN!!! actually it sorta is....but i cant see that at higher speeds the fan clutch even matters, cause you have airflow through the rad.

I'd check the HG's, before you replace the fan clutch. How many miles on the rig

FaYgo

220,000 yikes i know

DeathCougar

iTrader: (23)

oy so, the HG might be the issue. But, have them tested first so you dont waste anymore money. Is your oil milkey, or do you have oil film in your rad?

FaYgo

the oil looks normal honey brown and the coolant is just as translucent green as it was when i put it in last week.

ZUK

iTrader: (1)

That's pretty wierd. At highway speeds, there's so much volume of air rushing in the front that a bad fan clutch shouldn't change things much.....if the rest of the cooling system is working properly. A bad fan clutch would show up at slow speeds....around town driving....and climbing your road to your house.

Anyway, back to you Faygo.....your symptom of being ok around town at slower speeds....and shooting up at 70 mph is exactly what happened to me in my 87 Runner with 22RE with auto. I could drive around town and not have any over-heating at all. But it would happen within 10 miles of driving on the highway when the engine has to work harder obviously. MY radiator had 210k on it like yours and after replacing it with a new one the overheating issue was GONE 100%.

Unfortunately, it had been cycled in the red too many times during the diagnostic stage of the problem and 1 week later blew the headgasket. Lots of white smoke out the exhaust. Replaced the HG and life was good again.

So I think you should consider a NEW radiator. I don't think the cleaning that the shops do is helping much. Your 97 is new enough where you can probably get away with some hits to the red zone....so your HG will be ok. 220k on a 97 is alot of miles!

EDIT_____Now that I think of it....a friend of mine down in Tucson had a similar overheating issue on the highway about 8 years ago....he replaced the usual assortment of things but still had the issue. He also had the radiator rodded at a radiator shop and still had the problem. He then replaced the rad with a brand new one and problem solved. I have noticed alot of over-heating issues on these boards with Yotas and the radiator is low on the list of replacing.....but who am I to say because I did the same....

ZUK

iTrader: (1)

Faygo-- I have bought 2 radiators thru RadiatorBarn and been happy with the service and pricing.....my old 87 Runner ran 110 dollars for a 3 core.....looks like your newer Runner is a bit more pricey. see this.... $176.88 and free shipping....


http://www.radiatorbarn.com/s7.asp?a...L+ENGINE+SIZES

ZUK

iTrader: (1)

wow....nice deal here...

http://www.partstrain.com/products/S...RU-V6-005.html

FaYgo

sweet, thanks for all the help. i'm gonna try replacing the radiator and see if that works,

if not, who wants to come down for a head gasket changing party ! ;-)

give me about a week and i'll let you know what happens.

ZUK

iTrader: (1)

Don't forget about the $5 coupon at the top of the page! .....
http://www.partstrain.com/products/S...html?sku=P1998

FaYgo

oh yea, while i am waiting for my radiator to arrive here is another thing about this problem...

when it is heating up , if turn the steering wheel left to right , like i am trying to serpantine cones, the heat guage needle will slowly go back to normal temp range.

this would work all well and good except its an suv and if i try that manouver above the speed of 15 mph i take a very good chance of fliping my rig.

could my overheating problem possibly be connected to a power steering pump issue?

i needed to get a new radiator anyway cause i put a small hole in it when i removed the timing belt fan bracket cover , trying to get to the water pump.

just thought i would throw that into the stew. thought maybe it would bring up some more ideas.

DeathCougar

iTrader: (23)

The PS system is in no way connected to the cooling system....perhaps moving the truck back and forth is sloshing coolant around, and cooler coolant is getting to the sensor (indicating Water Pump, or Radiatior)

Btw, DONT USE aftermarket radiators. They always seem to have cooling problems. Buy a good used one, or a new factory one. Aftermarket replacements dont have the same number of cooling fins, have smaller water passages, and some styles are even made without drain plugs!!! (I have seen it many times, in many vehicles at work, so I know its true)

User 051420

FWIW, I have also used a RadiatorBard in the past. I got a condensor, and radiator from them and put it in m 97 (also over 200k miles). For the ~10k I put on it before I sold it, I had no problems with it. Two thumbs up for radiatorbarn.

MTL_4runner

You may also have a thermostat which is stuck open partway, but not fully open (hence the overheating on the highway only). They are cheap so you might as well put in a new one if you are going to put in a radiator too (I'd try that first to see if it cured it).

FaYgo

i was driving it today and it got up to normal temp, i had to stop on the side of the road for about 7 min. when i did i turned the engine of but left the key on acc with the radio goin when i got back the temp needle was all the way up to almost red, like 3/16 of an inch away. i started the engine and started driving and it slowly went down, mind you i was driving like 30 mph.

i think the overheating problem is worsening.

also i really really appreciate all the feedback you guys have given me. i am new to yotatech, and it has really helped me.
i used to be with team-integra.net but sold my acura and got a 4runner.

.........best thing i ever did.

GrizzlyNC

I completely agree ZUK.. I thought the same thing myself... but it fixed it and has never been an issue again.. but also after thinking back on it.. I do live in the mountains and most of the hwy's around here require there share of climbing, so I think maybe with the higher RPM's and climbing involved maybe that's why I had the issue?? I donno.. All I know is it seems to be fixed now.. I can climb my mtn with the AC on and it doesn't even budge..

tomstin

OK, off the wall here, what's the A/T fluid look like? Years ago I chased a overheating problem for a few weeks, then the A/T went out. The A/T fluid cools through the radiator, what was happening was the A/T fluid was SO HOT that it was heating up the radiator and not letting the coolant cool down. I know, a long shot, but it looks like you covered all the other bases...good luck on this one!

Finelygotone

I have a 99, V6 manual and just went through the same mess. My symptons were pretty similar and were exacerbated by trying to tow a boat. I could drive for a while at 50mph with the boat and no problem. Then suddenly, the temp would just take off and not cool down unless I ran my heater at full blast. If I had to climb a hill, I had to pull over to let it cool. The other interesting symptom was my fan clutch would not engage even when overheating. I looked at the whole cooling system and finally got down to the radiator as the cuplrit. I discovered this while taking simultaneous temp readings of the coolant and air going through the radiator. With the coolant at 210*, I found that the air in the mid section of the radiator was at 110* to 120* while the outer edges were 180* to 190*. I pulled the radiator out, put the cap on it and filled it full of cold water. A full 15" of core in the middle of the radiator stayed at room temp while the outer edges were cold to the touch. ( I have no other temp measuring devices....) There's the reason the fan clutch never engaged.... I pulled off the top and bottom tanks to find evidence of a water pump change in the past (here's why you don't let form-a-gasket fall into the motor...) - it had plugged about 1/3 of the passages. The other passages were blocked but I could not tell what with. But - it was definitely the problem. I went through Completeradiators.com and got a new unit for $150, free delivery. This unit is the same size and has the same functional characteristics as the OEM. I cannot vouch for it's long term quality but it is as good as the OEM in terms of function. I put the new unit in and and have towed the boat to 7000 feet in temps above 90* and not even had the temp guage move off of it's normal position. I also think that a new radiator will fix the problems....Good luck with your repair....

ZUK

iTrader: (1)

Ya, when I think back about my 87 and it would overheated on the highway.....so I pulled over and first thing I noticed was the fan clutch would spin easy.....I was at least expecting it to be stiff with all the heat coming thru the radiator. Didn't put 2 and 2 together about the center of the rad being clogged but it makes perfect sense now. Next time smeone has another rad that seems to overheat on the highway I will have them check for the loose fan-clutch and cool core. ZUK