Help ?!?!?!?

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bbailey

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New here and looking for help... Way confused on what I am missing so reaching out. 2000 4 Runner with a 3.4. Chasing an overheat issue and I have replaced the radiator, radiator cap, thermostat with a Toyota factory one and done head gaskets. Still overheating. T belt and water pump are newer (not done by me). T stat out and great water flow thru radiator and no heat once moving, t stat in and after a short drive the temp starts climbing way up and tons of heat... Any suggestions ??? Way lost and realize I am new here but hoping I am not alone experiencing this. Thanks in advance.
 
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Replace your water pump and t belt. If its more then 4 or 5 years old it needs to be done but I really think that is your issue.
 
If it gets hot in stop and go or slow moving traffic, fan could be the issue, if it does not get hot when moving steady like on the highway or 35+ mph. I had a harmonic balancer go bad that caused me to have these symptoms. The crank pulley was not turning the accessories, it happened on a 2jz engine. I am not to sure what the 4 runner has there as it is still new o me.
 
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Pioww said:
If it gets hot in stop and go or slow moving traffic, fan could be the issue, if it does not get hot when moving steady like on the highway or 35+ mph. I had a harmonic balancer go bad that caused me to have these symptoms. The crank pulley was not turning the accessories, it happened on a 2jz engine. I am not to sure what the 4 runner has there as it is still new o me.
Click to expand...

I'm going with one of these two, probably the fan clutch. The harmonic balancer, i.e crankbolt tightness should be ruled out just because the WP was done six months ago and there is always the risk somebody undertightened the crankbolt to the wopping 218 ft-lbs. required. I doubt this is it, but the consequences are bad enough that I would check it. If it is indeed over heating stopped and going slow and fine in motion, then fan clutch is almost certainly the case as you have done everything else. See below:

Testing the fan clutch:

If you have reason to suspect that the fan clutch is defective, here is the recommended procedure to verify the condition of the fan clutch.


1. Start the car (cold) with the hood open and note if the fan is turning, increase the engine RPM and note if the fan turns faster and the noise increases, if it does, first good indication, if it
does not increase speed/noise, clutch is bad and needs to be replaced. (Remember, this must be tested after the car has been off for and extended period, over night etc.)

2. Leave engine running and note if the fan starts to slow down after 2-5 minutes, speed/noise should diminish and even raising the RPM, the fan should not make as much noise as when first starting, if it does slow, this is the second good indication. If speed/noise does not decrease, clutch may be "frozen" and should be replaced.

3. Leave the engine idle and watch the temperature indicator. When normal operating temperature has been reached, some increase in fan speed/noise should be noted, in particular when the RPM is increased. If temperature is fairly stable and the fan noise/speed increases or cycles, third good indication. If temperature indication continues to increase, with no increase in fan noise/speed, clutch is defective and should be replaced.

4. After the engine is at normal operating temperature or above, is the only time that the "rolled up newspaper" test that many people talk about should be performed! Take some newspaper and roll it up into a long narrow tube. Be carefull, keep hands and fingers away from the fan while performing this test! With the engine at full operating temperature and idling, take the rolled up paper and insert it on the back side of the fan and try to reach the hub of the fan avoiding the blades until close to the hub. Push the rolled paper at the fan increasing the friction to the hub area of the fan. If the fan can not be stopped easily this is the fourth good indication, if it can be stopped the clutch is defective and should be replaced. Again, this test can only be performed when the engine is at or above full operating temperature.
Click to expand...

Props to the guy on a BMW board who wrote this; it also applies perfectly to our trucks.

Here is my mini-DIY on the swap--rest of thread has some good info, too:

http://www.yotatech.com/f2/1998-3-4-auto-4runner-overheating-issue-suggestions-216502/index4.html#post51509656
 
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TheDurk said:
I'm going with one of these two, probably the fan clutch. The harmonic balancer, i.e crankbolt tightness should be ruled out just because the WP was done six months ago and there is always the risk somebody undertightened the crankbolt to the whopping 218 ft-lbs. required. I doubt this is it, but the consequences are bad enough that I would check it. If it is indeed over heating stopped and going slow and fine in motion, then fan clutch is almost certainly the case as you have done everything else. See below:

Props to the guy on a BMW board who wrote this; it also applies perfectly to our trucks.

Here is my mini-DIY on the swap--rest of thread has some good info, too:

1998 3.4 Auto 4Runner, Overheating Issue, Suggestions? - Page 4 - YotaTech Forums
Click to expand...

thanks for the good info!
 
Had a similar issue with my Jeep, after changing everything found it was the

Thermostat Housing that had a crack.

Was brought to my attention by the crystalizing on the outside and the fact that it burned my friend in the process!
Something to check, especially since I replaced the H2O pump, Radiator (twice), new houses, countless flushes, new reservoirs, and mountings, fan, fan clutch, replaced with an electric fan (single, dual and back to single) and the list goes on!!!!!

Good luck.
 
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