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2007 Voodoo blue FJ cruiser
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Discussion Starter #41
"Probably"

But you took photos then cleaned it all off, so that you'll be able to tell if there are any new coolant "leaks," right? ;)




These clues say to me to make sure you have checked the transmission, transmission fluid, and transmission cooler well enough... From reading the summary and timeline, it looks like you haven't really dug into those yet. Your transmission cooler isn't gunked up or anything (inside or outside), right?

Automatic Transmission FJs have a portion of the main engine radiator dedicated to cooling the transmission - the little hoses out the bottom of the radiator. If you have an aftermarket transmission cooler, someone had to have disconnected those and... done something. Added your transmission cooler inline? Bypassed the original transmission cooler altogether? You mentioned you had your radiator replaced as part of this. Who did that? I don't suppose you have photos after your transmission cooler install and before the radiator replace just to double-check that the radiator replace didn't change anything out from underneath your assumptions about the transmission cooler?
hahahaha I’ll be sure to do that before I leave today 😉

And as for the transmission cooler, I installed that myself a few years ago. It is attached to the condenser on outside of the radiator, and is inline after the radiator transmission cooler and before the transmission. My transmission temps have not changed at all throughout all of this, it hasn't been getting hot whatsoever. It sits pretty steadily at 140–160F. I’ll give it a solid look over and see if any of the fluid is leaking or if the transmission hoses appear damaged or worn, or routed differently from when I did it. I can’t imagine if my transmission temps were so hot they overheat the engine but showed as normal on my gauge. But I’m not opposed to looking at anything. I’ll look it all over this evening and report back.
 

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The engine going up and transmission temperature does not. That’s a pretty impressive transmission cooler. If it was mine I’d circle around and confirm it is truly overheating. FJ Test I think question the accuracy of the sensor, that’s sounds like something I’d look at. You mentioned a mechanic that suspected head gasket. I believe that’s not much more than a half hour job to check that. Did that happen?


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2013 Trail Teams #181/2500<>< <*((^(((><
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I thought wow what a great idea for an invention, a radiator cap with a built in thermometer.Then I did a search... Not sure if it will help but maybe? Did not look up any for an FJ.

<>< <>< <>< <*((^(((><

1132207

High Pressure Radiator Cap With Temperature Gauge 1.8 Bar For Kawasaki Mule 3000 2x4 2001-2008

$31.77
Walmart
Free shipping
1132208

Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm 125 250 450

$23.98
eBay
8+ sold
1132209

Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm Husqvarna

$23.96
eBay
190+ sold
1132210

Mr. Gasket Thermocap Radiator Cap, 2470S

$37.99
Advance Auto Parts
1132211
Special Offer
1132213

Tusk 2.0 High Pressure Radiator Cap Temp Gauge Husqvarna Fe Fx Tc

$23.89
eBay
3+ sold

Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm Husaberg

$28.93
eBay
35
 

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2007 Voodoo blue FJ cruiser
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18 Posts
Discussion Starter #44 (Edited)
Okay so a lot happened in the last few hours.
The FJ overheated on the way home. But boy was he fighting to get me to my mechanic. He started getting hot, and I immediately turned on the hot air and started monitoring the temp. We drove for 15 miles with the temp hovering around 204F, and as we we’re approaching the exit he spiked to 215, and cooled down a bit, to 210. As we rolled up the exit he spiked to 220, and by the time we rolled around the corner into the mechanics he hit 225. God I love this truck, he has never failed to atleast get me to a mechanics!

I put him in park and quickly opened the hood to see if I could spot any coolant leaks or collapsed hoses. Coolant was everywhere, but even with the engine idling at 225, no hoses were collapsed and no visible leaking was occurring anywhere. The overflow pipe was the obvious source of all the coolant in the engine bay. After the engine cooled enough for me to reach in with a rag, I grabbed the two radiator hoses and both were very stiff.

My mechanic is convinced it’s a head gasket leak. The overflow bottle is completely full, and with no hose collapses and no transmission overheating, I’m starting to believe him. The transmission stayed at 150F even when the engine was 225F! It is a very large tranny cooler, and I’m glad it’s doing it’s job!
 

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Registered
2007 Voodoo blue FJ cruiser
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18 Posts
Discussion Starter #45 (Edited)
I thought wow what a great idea for an invention, a radiator cap with a built in thermometer.Then I did a search... Not sure if it will help but maybe? Did not look up any for an FJ.

<>< <>< <>< <*((^(((><

View attachment 1132207
High Pressure Radiator Cap With Temperature Gauge 1.8 Bar For Kawasaki Mule 3000 2x4 2001-2008
$31.77
Walmart
Free shipping
View attachment 1132208
Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm 125 250 450
$23.98
eBay
8+ sold
View attachment 1132209
Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm Husqvarna
$23.96
eBay
190+ sold
View attachment 1132210
Mr. Gasket Thermocap Radiator Cap, 2470S
$37.99
Advance Auto Parts
View attachment 1132211 Special Offer
View attachment 1132213
Tusk 2.0 High Pressure Radiator Cap Temp Gauge Husqvarna Fe Fx Tc
$23.89
eBay
3+ sold
Tusk 2.0 High Pressure Radiator Cap Temperature Gauge Ktm Husaberg
$28.93
eBay
35
This is really really cool. I will defiantly look into this.


The engine going up and transmission temperature does not. That’s a pretty impressive transmission cooler. If it was mine I’d circle around and confirm it is truly overheating. FJ Test I think question the accuracy of the sensor, that’s sounds like something I’d look at. You mentioned a mechanic that suspected head gasket. I believe that’s not much more than a half hour job to check that. Did that happen?


Sent from my iPhone using Tapatalk
I believe he did. Atleast he checked my oil for coolant, and did a visual inspection for bubbles in the coolant. he didn’t do an exhaust gas in coolant chemical test, but he told me he will preform that to see if that proves anything before pulling the heads. Tmrw he’s going to pull out the spark plugs and check for coolant, and break down as much as he can before he tears into it.

On a separate note, another FJ pulling a massive camper pulled in with a blown trailer tire, and we shot the bull for a bit. He was excited to see an FJ with 250k on it lol -not so much about the headgasket.
 

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2013 Trail Teams #181/2500<>< <*((^(((><
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So my thought is I would be worrying about it over heating even after it settles down. I think it would be worth it to take a quick visual. After a while you could see patterns and it may help in the troubleshooting process if needed. Maybe keep a log on your phone.

Regards, Andy

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Has anyone at least pulled spark plugs yet or done a compression test. Just the mention of pulling heads without those checks and the exhaust gas test is scary.


Sent from my iPad using Tapatalk
 

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2013 Trail Teams #181/2500<>< <*((^(((><
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So I tried to think of basics. Not sure if it's possible on an FJ but I thought... I wonder if the thermostat could be installed upside down. So I did a search and came across this article not for an FJ but just a car in general. Unfortunately, there was no update but that may because it was upside down.

Regards, Andy

<>< <>< <>< <*((^(((><

Default
I may have installed my thermostat upside down
--------------------------------------------------------------------------------

So I have been having some overheating problems after I flushed my coolant system and I think I may have installed the thermostat upside down.


After starting the car the temp will slowly climb (monitoring with scangauge) up to 180 and then keeps going up still about 220. If I increase the engine speed to 4k rpm or higher, the temp drops right away back to 180 and then slowly starts to climb again. As long as I am below 4k rpm then the temp will keep climbing.

At first I thought it was a bubble in the coolant system. But I came up with a method to remove all the bubbles from the coolant system, which it did, and it did not change the problem.

My guess right now is that at 4k rpm, the water pressure in the coolant system is enough to open the thermostat which causes the cool water in the radiator to flow into the engine and then when the engine speed reduces the thermostat closes again.

So my options are either a faulty thermostat (was just replaced 2 weeks ago) or its installed upside down.

What do you guys think, does my problem solving methodology make sense?
 

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2007 Voodoo blue FJ cruiser
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Discussion Starter #49
Has anyone at least pulled spark plugs yet or done a compression test. Just the mention of pulling heads without those checks and the exhaust gas test is scary.


Sent from my iPad using Tapatalk
My mechanic is pulling the spark plugs tmrw morning, and preforming a pressure test. He said he would also do a exhaust test. He told me he’d have an answer for me tmrw or Monday.


So I tried to think of basics. Not sure if it's possible on an FJ but I thought... I wonder if the thermostat could be installed upside down. So I did a search and came across this article not for an FJ but just a car in general. Unfortunately, there was no update but that may because it was upside down.

Regards, Andy

<>< <>< <>< <*((^(((><

Default
I may have installed my thermostat upside down
--------------------------------------------------------------------------------

So I have been having some overheating problems after I flushed my coolant system and I think I may have installed the thermostat upside down.


After starting the car the temp will slowly climb (monitoring with scangauge) up to 180 and then keeps going up still about 220. If I increase the engine speed to 4k rpm or higher, the temp drops right away back to 180 and then slowly starts to climb again. As long as I am below 4k rpm then the temp will keep climbing.

At first I thought it was a bubble in the coolant system. But I came up with a method to remove all the bubbles from the coolant system, which it did, and it did not change the problem.

My guess right now is that at 4k rpm, the water pressure in the coolant system is enough to open the thermostat which causes the cool water in the radiator to flow into the engine and then when the engine speed reduces the thermostat closes again.

So my options are either a faulty thermostat (was just replaced 2 weeks ago) or its installed upside down.

What do you guys think, does my problem solving methodology make sense?
the orientation of the thermostat is with the hose angled down, I am almost positive this is the same way it was before I replaced it. Is that the correct orientation?
 

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The thermostat is a disc with a spring etc on it. it sits inside the housing that you mention.
Open the housing, take a photo of it in the housing in the orientation that it currently is and post the pic here, then take the thermostat out, and close the housing back up. refill the coolant and see if you can get it to overheat - it should struggle to make normal running temp unless you're towing a horse float up a mountain with your foot on the boards.
Please report back on the result of running without the thermostat.

Then - Buy a new genuine toyota/denso thermostat and check for correct alignment and install it, try again to get it to overheat.

This is MUCH MUCH cheaper than replacing a head gasket.

 

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Any update? was it a reversed or defective thermostat?
 

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Discussion Starter #52
Okay guys I have an update. Sorry for the long time, the mechanic at the shop who is familiar with the FJ was on vacation last week and they wanted to wait until he returned to continue tackling the problem, which was fine by me. I’d rather have someone familiar with it working on it then someone who isn’t.

We checked the thermostat again, and all was in order. After doing an exhaust test as well as an oil test, we determined the headgasket appeared to be leaking slightly.
I gave them the green light to pop the heads, and it became immediately apparent the heads are the problem. We think the engine probably sat for a long time in the old junked FJ it was donned from and the gasket sat without being run, and had some small cracks. It doesn’t leak until the pressure really builds in the engine and it really heats up.

The heads are at the machine shop now, and the job is in the middle of being done.

The shop told me they would eat the cost of all the labor up until the headgasket, because they don’t feel right charging me for stuff that didn’t fix the problem, which I really appreciate.

I’ll keep you guys posted as I test drive the rig a bit, it’s scheduled to get back to me later this week.
 

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Yeah, the overflowing coolant expansion tank with the engine coolant temperature at only 225F is a very strong indicator of a head gasket leak (post #24).

Assuming a 50:50 glycol:water coolant, and a stock 16 PSI radiator cap, the coolant won't boil until almost 270F, so the 225F coolant temperature you saw would NOT boil the coolant and cause the coolant expansion tank to overflow ... something else was applying pressure greater than 16 PSI to the cooling system, opening the radiator cap, and displacing coolant into the expansion tank.

The only logical source of the pressure is a leaking head gasket, where the peak pressure in the cylinders can be almost 1,000 PSI at full throttle. It doesn't take much of a leak to overpressure the cooling system and force coolant out.

You just added another 100K miles to your FJ's potential life, if you take good care of him.
 

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Post pics of the gaskets if you can
 
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