Overheating Issues

[BlairB]

Well this is somewhat a problem revisted, unfortunately.

Basically I have severe problems with my 4runner overheating while driving off road. If on the throttle hard for any period of time (like climbing a hill) my temp will shoot right into the red.

I bought my car into Toyota and when they looked at it they said it was due to all the mud and dirt I had in the radiator (oops) and they said that should take care of everything. It definitely has not.

After my car has gotten all the way into the red the only ways to cool it down are to turn it off and wait or drive a trail while cruising at a constant speed with little work for the engine required (basically allowing fresh air to flow), if I just stop and leave it running it keeps climbing.

My thermostat is fine (we checked that after I had it randomly overheat once) and my fluids are all at the right levels and I have not had problems losing any of the coolant other than to boiling over.

When we took a day trip to Hungry Valley this weekend my 4runner would be running in the red a huge amount of the time, and no other 4runner strayed away from having their temp totally normal (and I didn't even use a/c!).

I feel this problem has gotten worse, if anything and I was curious if anyone had any idea what they think it could be?

 

[josh220]

Overheating can be caused by anything that decreases the cooling system's ability to absorb, transport and dissipate heat: A low coolant level, a coolant leak (through internal or external leaks), poor heat conductivity inside the engine because of accumulated deposits in the water jackets, a defective thermostat that doesn't open, poor airflow through the radiator, a slipping fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose water pump impeller, or even a defective radiator cap.

One of nature's basic laws says that heat always flows from an area of higher temperature to an area of lesser temperature, never the other way around. The only way to cool hot metal, therefore, is to keep it in constant contact with a cooler liquid. And the only way to do that is to keep the coolant in constant circulation. As soon as the circulation stops, either because of a problem with the water pump, thermostat or loss of coolant, temperatures begin to rise and the engine starts to overheat.

The coolant also has to get rid of the heat it soaks up while passing through the block and head(s). So the radiator must be capable of doing its job, which requires the help of an efficient cooling fan at slow speeds.

The thermostat must be doing its job to keep the engine's average temperature within the normal range. If the thermostat fails to open, it will effectively block the flow of coolant and the engine will overheat.

Your engine may not be overheating at all. Your temperature gauge or warning lamp may be coming on because of a faulty coolant sensor. Sometimes this can be caused by a low coolant level or air trapped under the sensor.

 

[BlairB]

Your engine may not be overheating at all. Your temperature gauge or warning lamp may be coming on because of a faulty coolant sensor. Sometimes this can be caused by a low coolant level or air trapped under the sensor.

I had hoped something like that was the case, but you can physically feel and smell a huge difference between normal and when the warning lights are coming on, it is a horrible burning dirt smell haha and you can feel major heat being kicked off the engine

 

[CJ3Flyr]

When it's hot do you hear lots of fan noise? Is your fan enaging like it should?
:cheers:

 

[leftyguns21]

well its nice to know i wasnt the only person with this issue. on my 3rd gen i had this problem, i replaced the t-stat 3 times, the waterpump, flushed radiator, replaced fan clutch, fan clutch belt still not resolved. i would have to drive w. the heater on in some cases if i was idle in traffic in the heat or if i was heading to the mtns no matter what the temp (it has done it even when outside temp is in teens). i took it to several dealerships and it never got resolved, so that and the high mileage on her made me decide to trade my baby in for a new ride.

good luck i feel your pain, wish i was more help. the explanation i got was 'its normal' but like you, i saw several other 4runners driving around w/ no issue.

 

[BlairB]

When it's hot do you hear lots of fan noise? Is your fan enaging like it should?
:cheers:

Yeah the fan is engaging like it should hmmm

 

[BlairB]

well its nice to know i wasnt the only person with this issue. on my 3rd gen i had this problem, i replaced the t-stat 3 times, the waterpump, flushed radiator, replaced fan clutch, fan clutch belt still not resolved. i would have to drive w. the heater on in some cases if i was idle in traffic in the heat or if i was heading to the mtns no matter what the temp (it has done it even when outside temp is in teens). i took it to several dealerships and it never got resolved, so that and the high mileage on her made me decide to trade my baby in for a new ride.

good luck i feel your pain, wish i was more help. the explanation i got was 'its normal' but like you, i saw several other 4runners driving around w/ no issue.

So was there any sort of final verdict?

Or just rid yourself of it so you didn't have to worry about it?

 

[Mark86]

Have you noticed any coolant leaks from under your truck? I would look at your hoses and make sure they are alright. Since the dealer can't seem to fix the issue, maybe it is time for the lemon law. My 2005 has been taken through 105 degree heat, snow piles (where I had to really work the engine to rock it out), and other harsh conditions. My temp gauge will never budge from the middle regardless! Something seems very wrong with your truck because how many members here have gone offroading and not encounter any problems?

 

[BlairB]

Have you noticed any coolant leaks from under your truck? I would look at your hoses and make sure they are alright. Since the dealer can't seem to fix the issue, maybe it is time for the lemon law. My 2005 has been taken through 105 degree heat, snow piles (where I had to really work the engine to rock it out), and other harsh conditions. My temp gauge will never budge from the middle regardless! Something seems very wrong with your truck because how many members here have gone offroading and not encounter any problems?

Nope no coolant leaks to my knowledge (I check the coolant pretty often and only loose them when off roading after boiling over), and I checked all the hoses to the best of my ability and they all looked fine.

It is understandable that they originally blamed the problem on the amount of mud and dirt in the radiator the first time, I know I would have done the same.

I took it back in this morning and they are going over the car and will figure out what is the problem. I don't actually take my 4runner to a dealer, but rather to the service garage at National HQ in Torrance, so I have faith they will figure it out. They were very apologetic for not having done a more thorough diagnosis the first time.

It will be interesting to see what exactly the problem was, but in the mean time I have a stock 2008 v6 4wd 4runner to blast around in, and I get to use their gas instead of mine

 

[BlairB]

A little update, the worst case scenario is happening with my car. They have had multiple techs try to figure out what the issue is and they cannot find anything wrong with the car

They understand the problem is occurring off road, mainly when the engine is under some stress (climbing up a hill, for example) and are trying to figure out the best way to replicate this sort of condition to determine the problem, but as of now there is no luck.

I am keeping my fingers crossed...

 

[leftyguns21]

A little update, the worst case scenario is happening with my car. They have had multiple techs try to figure out what the issue is and they cannot find anything wrong with the car

They understand the problem is occurring off road, mainly when the engine is under some stress (climbing up a hill, for example) and are trying to figure out the best way to replicate this sort of condition to determine the problem, but as of now there is no luck.

I am keeping my fingers crossed...

you have the mystery car like i did. they could never get the problem to replicate so they thought i was crazy, but i finally took it to a dealership near the foothills and the mechanic had to drive it hard up the pass deep into the mtns to get it to replicate. couldnt figure out how to fix it...but at least saw i wasnt nuts.

 

[josh220]

A little update, the worst case scenario is happening with my car. They have had multiple techs try to figure out what the issue is and they cannot find anything wrong with the car

They understand the problem is occurring off road, mainly when the engine is under some stress (climbing up a hill, for example) and are trying to figure out the best way to replicate this sort of condition to determine the problem, but as of now there is no luck.

I am keeping my fingers crossed...

Will you not have your truck for the weekend then?

 

[BlairB]

Will you not have your truck for the weekend then?

I am hoping they should have it fixed by then, if they can't figure out anything by Friday I will go pick up my rig and tell them I am going to go get it to overheat again so maybe I can have more to tell them and then bring it back to them again on Monday.

If not, I do have the 2008 4wd 4Runner that they loaned me that has less than 2,000 miles on it and could use some breaking in....

 

[josh220]

I am hoping they should have it fixed by then, if they can't figure out anything by Friday I will go pick up my rig and tell them I am going to go get it to overheat again so maybe I can have more to tell them and then bring it back to them again on Monday.

If not, I do have the 2008 4wd 4Runner that they loaned me that has less than 2,000 miles on it and could use some breaking in....

Haha I'm sure they would love that.

 

[CJ3Flyr]

To absolutely eliminate any skepticism on their part take a vid camera and show the terrain/conditions etc. and the dash needle.

As basic at it sounds maybe having a radiator shop check the flow through the radiator. Maybe something goofy happened in production of the radiator, a shop rag jammed in one of the end tanks or something. A second be to might be dyno the T4R. If it comes out weak and it over heats maybe you have a defective, clogged converter (although that

 

[BlairB]

To absolutely eliminate any skepticism on their part take a vid camera and show the terrain/conditions etc. and the dash needle.

As basic at it sounds maybe having a radiator shop check the flow through the radiator. Maybe something goofy happened in production of the radiator, a shop rag jammed in one of the end tanks or something. A second be to might be dyno the T4R. If it comes out weak and it over heats maybe you have a defective, clogged converter (although that

 

[BlairB]

To absolutely eliminate any skepticism on their part take a vid camera and show the terrain/conditions etc. and the dash needle.

Also, they realize that the terrain and conditions shouldn't have any effect since I explained how I was having this problem while doing identical trails with 3 other 4Runners (Josh220, T4Rfun and geigerz2001) and I would be boiling over while their temp would not budge from the middle, even with their a/c on full!

 

[CJ3Flyr]

Well it sounds like you're 3/4 of the way to a fix. Often times it seems the hardest part is convincing 'them' that a problem exists. It's good to hear they're believe you and they're doing the right thing.

:cheers:

 

[Demon Dave]

Just a thought, but if the problem only occurs when you're off-roading then perhaps the could be a problem with the 4lo gear? Excessive resistance/binding of some sort putting extra stress on the engine?

Just a thought. I hope you get it sorted.

 

[Routty]

Did you do some serious mudding before the first occurence? I know of people who have had the same issue with an Xterrra. They got their radiator all clogged with mud which severely decreased its ability to cool. They tried to wash it out with a hose, but the problem still occured. The thing looked clean, but once they used a high pressure washer they were amazed at how much mud and dirt came out. After that no more problems. Just a thought.....