Please Help, Cooling Issues and I'm Confused!

psraff

psraff

New member
Hey Everyone... Please refer to a thread I started a few days ago.

http://www.toyota-4runner.org/3rd-gen-t4rs/194621-idea-dual-water-temp-guages.html#post1989933

It all started with an opinion of an idea. But the more I worked on my Cooling the worse it got. Long story short....

New TStat (jiggle valve in 6 O'clock position)
New Fluid (Toy Red)
Good Fan Clutch (new several years ago)
Temps always ran a bit high per Scan Gauge
Dash Gauge never was over half way

I put my EFans back in and temps higher so I took them out again.

Now temps higher then before, some things I haven't noticed before have me worried... Please confirm if I have a symptom and what could the cause be. I'm confused and stressed.

Again please refer to other thread for more details....

Thanks in advance!!!
 
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So I've read the fine points of the other thread, and I have a question. I don't own a scangauge, but any chance since it's an OBDII scanner, wouldn't it be reading the temps of your *potentially* busted temp sensor? I might be horribly wrong....but it's seems like a simple potential solution
 
The chances of me reading one thread to comment on this one are pretttttty slim... So thanks for the cliff notes =D

What are you temps at? On the scangauge, that is.

To see if the coolant is moving through the system you should be able to just give the upper rad hose a squeeze and feel it moving... Also, if the system is burping, that'd be a pretty good hint.
 
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My 2 cents: I've read some threads on here about SCII gauge readings and honestly, I take those with a grain of salt. I would rely on a quality aftermarket gauge/sender before trusting the reading of a gauge that just displays the data sent to the ECU.

Maybe those sensors are calibrated slightly on the high side to nerf the margin of error.

You say your temp reading in your dash cluster never goes over half? Why not just trust that gauge? I'd have to reread your other thread, but is your SCII data the only indication that your rig is running hot?
 
SpidermanGeek said:
My 2 cents: I've read some threads on here about SCII gauge readings and honestly, I take those with a grain of salt. I would rely on a quality aftermarket gauge/sender before trusting the reading of a gauge that just displays the data sent to the ECU.

Maybe those sensors are calibrated slightly on the high side to nerf the margin of error.

You say your temp reading in your dash cluster never goes over half? Why not just trust that gauge? I'd have to reread your other thread, but is your SCII data the only indication that your rig is running hot?
Click to expand...

this was exactly what I was trying to say, just much more eloquently!
 
I think you're worried about nothing honestly. You're still in normal operating temperature range. How high up are you? The fact that it isn't riding the thermostat may be a result of altitude, or a production variances in the thermostat. Or as others have mentioned, the temperature reading may not be that accurate. I'd go buy a brand new Toyota thermostat and put that in to start with.

The chances of the water pump not working properly are pretty slim.
 
Thanks guys! I'm feeling better. The biggest thing that worried me is my Scangauge readings are higher then just a day or two ago which caused me to think something isn't right. Yesterday I saw a temp of 209* on the Scangauge. I've had two different Scangauges in this truck and they both have both read a little high. I normally see temps in the 202 - 204* range. Even my tranny temps always seemed a bit high compared to what others on here have posted ( I've had two different aux tranny coolers in over the years).

I will order a new ECT sensor today, with a new Toyota TStat. I'll also work on a quality temp gauge setup just for a peace of mind.

The Scangauge is my only indication of my higher temps. My dash gauge has NEVER gone over half way. So I guess you guys are right. I'm just stressing over nothing... Just don't want to start a road trip and get stranded out in the middle of no where.

Ok Everyone! Thanks again!!
 
At this point I would suggest you take it to someone for bumping.

I won't cost much and is worth a shot. I have been told these trucks are difficult to burp fully and air pockets cause you exact problem.

I tried burping mine using the DIY methods and no luck.
 
BrianSD_42 said:
At this point I would suggest you take it to someone for bumping.

I won't cost much and is worth a shot. I have been told these trucks are difficult to burp fully and air pockets cause you exact problem.

I tried burping mine using the DIY methods and no luck.
Click to expand...

Yep.... Even though I did everything I possibly could think of, there is always that possibility. Going to call and order my ECT Sensor as well.

Thanks!
 
BrianSD_42 said:
At this point I would suggest you take it to someone for bumping.

I won't cost much and is worth a shot. I have been told these trucks are difficult to burp fully and air pockets cause you exact problem.

I tried burping mine using the DIY methods and no luck.
Click to expand...

These and the 2nd Gens are known for holding air and not giving it up.

Often what happens is that air will collect near the ECT and Temperature sending gauges and give false readings.
 
The little hole is supposed to be clocked to allow air to escape past the thermostat. The thermostat regulates the use of the cooling system. Do you know what temp it is rated for?

Also change the rad cap, everybody forgets that this is an important part of the cooling system. It regulates pressure in the system and prevents the coolant from BOILING. If it's not holding the rated pressure you could be getting large air pockets. It's cheap, buy a new one from Toyota.

Scaling in The radiator from hard water (mineral deposits) can restrict flow and further reduce heat transfer to the air. Mud or dirt etc caught in the rad between the fins can also cause overheating, I see this on 4x4 trucks lots, wash that ish out at the car wash.

A weak waterpump can also cause overheating, the bearing may be loose but it's not weeping/leaking. I see this more on American stuff, but it's not an impossibilty.

Last but not least is an internal headgasket leak, combustion gasses can leak into the cooling system causing air pockets and over pressuring, There is a special test kit to check for this, but you can visually check for air bubbles inter the rad cap while hot and running.


A tip for bleeding the cooling system, get it hot, put the rad cap in and rev the piss out of it for a minuite or two, say 3k rpm. Then immediately shut the engine off. The rad cap must be on for this to work. You might here a gurgling or slurping noise as it sucks in a ton of coolant.

Also, FYI, when ECT sensors fail they almost always read cold. They are a negative coefficient sensor, meaning as temps go up, electrical resistance goes down. When electrical components fail their resistance typically goes up, meaning the sensor would read cold.
 
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I also forgot, did you dilute your coolant or is it pure glycol? If you don't dilute it, it won't have the proper cooling properties, you can check the percentage with a tester. Ideal mix is 50/50 water coolant
 
Paperjam said:
The little hole is supposed to be clocked to allow air to escape past the thermostat. The thermostat regulates the use of the cooling system. Do you know what temp it is rated for?

Also change the rad cap, everybody forgets that this is an important part of the cooling system. It regulates pressure in the system and prevents the coolant from BOILING. If it's not holding the rated pressure you could be getting large air pockets. It's cheap, buy a new one from Toyota.

Scaling in The radiator from hard water (mineral deposits) can restrict flow and further reduce heat transfer to the air. Mud or dirt etc caught in the rad between the fins can also cause overheating, I see this on 4x4 trucks lots, wash that ish out at the car wash.

A weak waterpump can also cause overheating, the bearing may be loose but it's not weeping/leaking. I see this more on American stuff, but it's not an impossibilty.

Last but not least is an internal headgasket leak, combustion gasses can leak into the cooling system causing air pockets and over pressuring, There is a special test kit to check for this, but you can visually check for air bubbles inter the rad cap while hot and running.


A tip for bleeding the cooling system, get it hot, put the rad cap in and rev the piss out of it for a minuite or two, say 3k rpm. Then immediately shut the engine off. The rad cap must be on for this to work. You might here a gurgling or slurping noise as it sucks in a ton of coolant.

Also, FYI, when ECT sensors fail they almost always read cold. They are a negative coefficient sensor, meaning as temps go up, electrical resistance goes down. When electrical components fail their resistance typically goes up, meaning the sensor would read cold.
Click to expand...


Yep, Yep, Yep, and Yep. LOL

I've read in the Hynes manual that the Jiggle Valve should be in the 12 O'clock position. But in this forum, it's been noted many times that it should be in the 6 O'clock for our 3.4L engines. So I put mine in the 6 O'clock. If that's wrong, please correct me.

Coolant is diluted. Tested to about -20 \ ~260 * (I think it was 260.. I don't quite remember. Up here I care more about freeze point.) But yes, it is deluded.

I'm pretty sure I've got a clean radiator. There's a massive temp difference from the top and bottom hoses. When I pull the plug, there's no hesitation of fluid draining (I've even removed the TStat housing with a full radiator to get mass, instant flow and there's instant discharge. I've caught the fluid and inspected it and there is little to no solids in it. Fins are clean on the outside.

I just put an order in for a new ECT Sensor, O-Ring, TStat, Rad. Cap, and crush rings (all Toyota) from Camelback Toyota in AZ.

Alaska prices are stupid high. ECT from Camelback - $49... Here - $89
TSTat - There $16. Here $32
Cap - There $10.50 Here $23.....

So two day shipping (which doesn't exist up here) was $19 from AZ.

Once that is changed and I monitor the temps, I'll see where I stand. Then have a shop burp it. See where I stand again. I'm at 185K so it's almost time for a Timing belt and water pump anyway so I will do that this summer if I don't see a difference.

I'll look into a Auto Gauge Water Temp so I have a direct reading (not going through ECU) and see how those numbers compare.

Thanks Everyone!! I think my road trip for Saturday is back on. I feel better about this.
 
psraff said:
I've read in the Hynes manual that the Jiggle Valve should be in the 12 O'clock position. But in this forum, it's been noted many times that it should be in the 6 O'clock for our 3.4L engines. So I put mine in the 6 O'clock. If that's wrong, please correct me.

.
Click to expand...

I think you're good there. I just pulled mine out to do the water pump, and it was at the 6 O' Clock position. My truck runs at a consistent 180-185 degrees, and that's in FL. From what I've read from other members they run a little hotter with it at the 12 O' clock, and the Toyota manual says to put it at 6. I have no idea why it would make a difference, but it seems to. :shrug:
 
Just a thought, especially since putting the efans in raised the temp. If your in such a cold climate, maybe the coolant is cooling too much and shocking the thermostat closed a little more then it should be since its on the intake side of the cooling system. Maybe try a cheapy 10 degree colder auto parts store tstat to test and see if it makes a big difference.
 
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