Engine Temperatures

Dous

Dous

New member
So I just got my UltraGauge put in last week, to monitor engine temps. As most of us know the temperatures around the country are ridiculous. It was 102 today in Raleigh, and I went to go mess around on a local little hill climb.

Driving down there on the highway I was seeing temps between 190-195, nice and cool. Slowing down in the city I saw it up to 202, still not too bad.

Once I put it in 4LO and started climbing up a small wall the temperatures instantly spiked, up to 235!

Just to give people an idea of how pathetic the stock gauge is, it stayed at the same location between 190-230. Once I hit 235 it moved but only a bit. Keep in mind I am also running electric aux fans in addition to the main engine fan, and they were cranked on.


My question is, what temperature become unsafe for these engines, when should you turn it off and let it cool?

Is there something wrong with my cooling system?

Whats the highest temperatures you guys have seen?
 
Register to hide this ad
I agree the stock gauge is aweful. I once hit 240 on the beach and the gauge was pegged in the middle. I just recently flipped my thermostat so the jiggle valve is on the bottom and I am around 193 now. I used to be around 205. Have you done the deckplate mod? That makes a noticeable improvement when I'm on the beach. The time I hit 240 the plate was in, with it out I never went above 207 and that was when the 4runner was averaging 205 temps.
 
Acidmeld said:
I wouldn't worry till you get around 260-270.
Click to expand...
Is that water temperature? It sounds more like oil temperature. It's OK for oil temperature if you don't have an oil cooler but if you have a cooler it should be lower. It's way too high for water temperature though.
That might be high enough to crack or warp the head or cause a leaking head gasket. If mine gets over what the thermostat is set to, 190 I think, then it has a problem that needs to be fixed.
 
Last edited:
stevec5000 said:
Is that water temperature? It sounds more like oil temperature. It's OK for oil temperature if you don't have an oil cooler but if you have a cooler it should be lower. It's way too high for water temperature though.
That might be high enough to crack or warp the head or cause a leaking head gasket. If mine gets over what the thermostat is set to, 180 I think, then it has a problem that needs to be fixed.
Click to expand...

180 is when the thermostat opens, not the max temp. You will never see operating temperatures at 180 when it is this warm. Maybe if it was sub zero.

I did have the deckplate cover installed, so that will be another thing to try. I might just buy a lower temp thermostat
 
Wow, 5VZ temps are higher than I expected, compared to the 3RZ. I did a bunch of 4LOing yesterday and peaked at 193F. Max it's ever hit was 205F on a blistering hot day. Pretty sure my thermostat opens at 180, I often get pegged right about there.
 
I never exceeded 195 in moab. I would get a 170* thermostat (especially with the S/C) and flush the radiator. That should make a good difference.

Remember water boils at 212. And even though its a mixture so it has a higher boiling point than that, the water in that mixture can vaporize and really increase pressure leading to a blown head gasket. So those temps really need to come down.
 
ChildrenOfBodom said:
Wow, 5VZ temps are higher than I expected, compared to the 3RZ. I did a bunch of 4LOing yesterday and peaked at 193F. Max it's ever hit was 205F on a blistering hot day. Pretty sure my thermostat opens at 180, I often get pegged right about there.
Click to expand...

Yea my 3vz never got hot. I always ran the AC off road and never batted an eyelash. Now, I never run the AC if its above 80 off road.

The thing going for that engine is that you have the same cooling system as the 5vz-fe.
 
4-Ripcord said:
I never exceeded 195 in moab. I would get a 170* thermostat (especially with the S/C) and flush the radiator. That should make a good difference.

Remember water boils at 212. And even though its a mixture so it has a higher boiling point than that, the water in that mixture can vaporize and really increase pressure leading to a blown head gasket. So those temps really need to come down.
Click to expand...

When the pressure increases so does the boiling point, so it won't boil until well above 212.

But yea, still too hot, a thermostat will be in order. I did just flush the cooling system for summer, with a 75/25 mix, more water than antifreeze, because water cools better.
 
Last edited:
Find out if your radiator has been replaced or not. If not, get one of the 2 or 3 core aluminum radiator. They work great and they're cheap.

I used one on my 2UZ swap and in this 104 degree weather, it has not raised up past mid point on the temp gauge. I also drove on the beach which is strenuous on cooling systems and it did not even flinch.

Biggest complaint about the V8 swaps is over heating and I had not had one problem and I run the AC all the time.
 
+1 with making sure of the correct location for the T-stat jiggle valve. Check the fan clutch as well.

How old is the H20 pump?
 
My current supercharged 2001 has never broken 200F. Even when it's 105 outside, it sits at 186 most of the time.

Seeing other 4runners run considerably hotter (205-210 under normal conditions), leads me to believe a couple things: my fan clutch is strong, my thermostat is working correctly, and my radiator is clean.

EDIT: The only time I've had it in 4Lo for an extended time was climbing Engineer pass in CO. But it was only 45 degrees outside. Engine temp never passed 190.
 
Even here in Arizona, on a 115 degree day, my temps are always at 195-197. The only time I have ever seen higher is wheeling in the desert with ac on full and barley any breeze, and that was only 202.
 
quicksilvr said:
My current supercharged 2001 has never broken 200F. Even when it's 105 outside, it sits at 186 most of the time.

Seeing other 4runners run considerably hotter (205-210 under normal conditions), leads me to believe a couple things: my fan clutch is strong, my thermostat is working correctly, and my radiator is clean.

EDIT: The only time I've had it in 4Lo for an extended time was climbing Engineer pass in CO. But it was only 45 degrees outside. Engine temp never passed 190.
Click to expand...

I have a feeling you have a TRD thermostat installed. My temps go to 190 to 195 now and just sit there.
 
Dous's set up is a bit hardcore though. He is using some type of programmer that lets him adjust and get the right amount of fuel into his motor. Getting the stoichiometric perfect air fuel ratio makes power. The byproduct of making a lot of power is a lot of heat.
 
a 170 stat wont lower temps, it will only lower when the stat opens.
if fact, a lower stat can actually increase temps, because anything above that, it will be open all the time.
depening on conditions, having the coolant in the radiator longer will help cool it down.

if the stat is always open, its not in the rad for very long, hence not getting a chance to cool down.
 
Singtoe said:
Find out if your radiator has been replaced or not. If not, get one of the 2 or 3 core aluminum radiator. They work great and they're cheap.

I used one on my 2UZ swap and in this 104 degree weather, it has not raised up past mid point on the temp gauge. I also drove on the beach which is strenuous on cooling systems and it did not even flinch.

Biggest complaint about the V8 swaps is over heating and I had not had one problem and I run the AC all the time.
Click to expand...

That is an option, I still have the stock radiator

quicksilvr said:
My current supercharged 2001 has never broken 200F. Even when it's 105 outside, it sits at 186 most of the time.

Seeing other 4runners run considerably hotter (205-210 under normal conditions), leads me to believe a couple things: my fan clutch is strong, my thermostat is working correctly, and my radiator is clean.

EDIT: The only time I've had it in 4Lo for an extended time was climbing Engineer pass in CO. But it was only 45 degrees outside. Engine temp never passed 190.
Click to expand...

Something is definitely amiss with mine then



Singtoe said:
Dous's set up is a bit hardcore though. He is using some type of programmer that lets him adjust and get the right amount of fuel into his motor. Getting the stoichiometric perfect air fuel ratio makes power. The byproduct of making a lot of power is a lot of heat.
Click to expand...

:pimp:



SO....something is definitely not right with my cooling system, driving home today it was 100 degrees, going 55 MPH I was sitting at 205. That is not right.

I have confirmed I have a 170 degree T-stat, but I am going to go ahead and replace it, cheap enough. What is the correct position for the little jiggle switch?
 
You must log in or register to reply here.

Members online

Total: 455 (members: 4, guests: 451)

Forum statistics

Threads
278,304
Messages
3,554,033
Members
248,014
Latest member
xf-bot+t4r

Share this page

Back
Top