Coolant temp increases on hills?

Status
Not open for further replies.
G

GTO52

Joined
Nov 9, 2009
Messages
124
Location
Cape Town , South Africa
2 years ago I had problems with my 95 Toyota pickup(22R engine) I was traveling long distance.I had been driving +/-2hrs when I started to climb a mountain pass I noticed my water temp gauge moving up, it got to 3/4 and as soon as I started driving down hill it went back to its normal position.I managed to carry on by putting the heater on for steep hills.Anyway when I got back to town,I tried to see if the gauge would move up again on hills but it was fine? It only seemed to do it when driving long distance?
I spoke to mechanic friend of mine he reckoned it was the thermostat sticking.So I replaced it with an OEM one.Problem solved, it has been fine now for 2 years.
I was driving long distance on Friday and experinced the exact same symptoms?
The pickup still has original radiator,its on its 3rd water pump(replaced 2 years ago),radiator cap replaced 2 years ago,all hoses have been replaced.
Any ideas?
 
Thermostat could've failed again but that's not exactly a part that has a short lifespan. It should last a really long time.

When's the last time the fluid was flushed? Maybe there's an obstruction in the radiator somewhere?
 
I flushed it 2 years ago when I experinced the problem the first time.I also recently changed to Toyota Pink.
Maybe it is the radiator it is 15 years old after all?
Some of the fines have fallen off from corrosion but the core still looks okay?
 
The fins are key because they carry heat away from the tubes and are cooled by the air passing over them.

You don't say how long the hills are, or how often you take such drives. If it's infrequently, I'm not sure I'd do anything other than maybe turn on the heat when you are climbing such a hill.

If you know you can find a quality replacement radiator and plan to keep the truck a good while longer, then it may be worth replacing the radiator.

Otherwise, maybe just leave well enough alone for now and watch that gauge when you are traversing mountain passes.
 
I'm having a similar problem with my 93 Aerostar. I'm certain it is not the thremostat. I'm pretty sure the radiator needs a good flushing or replacement. I gets hot but not into the danger zone. I checked temp on a high point of the engine, the top of the thermostat housing in my case and IIRC it got to about 225* F with a lazer thermometer. I'll flush it out next chance I get and see if it improves any.

Typically it would run around the letter O in the word NORMAL. It now gets between the A and L, that is when I took the temp reading. The funny thing is it will quickly shoot down to the A once the load is off the engine.

If I were you I'd try flushing it again, and get an exact temp reading like I did to see exactly how hot it is getting.
 
Originally Posted By: demarpaint
I'm having a similar problem with my 93 Aerostar. I'm certain it is not the thremostat. I'm pretty sure the radiator needs a good flushing or replacement. I gets hot but not into the danger zone. I checked temp on a high point of the engine, the top of the thermostat housing in my case and IIRC it got to about 225* F with a lazer thermometer. I'll flush it out next chance I get and see if it improves any.

Typically it would run around the letter O in the word NORMAL. It now gets between the A and L, that is when I took the temp reading. The funny thing is it will quickly shoot down to the A once the load is off the engine.

If I were you I'd try flushing it again, and get an exact temp reading like I did to see exactly how hot it is getting.


Yes it does seem the same as my problem, mine never actually got into the red portion of the gauge and like you said once the load is off it goes back to normal fast.
 
That 22R is a fantastic engine!!

I've seen some water pumps' fins get eroded over time, but that shouldn't be so soon in your case.

To be safe, if it bothers you, you could do a chemical flush in case there are deposits and poor flow somewhere in the block. A good indicator would just be looking in the rad/hoses... for buildup. If it's clean I wouldn't chemical flush but might have a shop to a reverse pressure flush.

But frankly.... I'm going to agree with posts above-- radiator likely, and just watch the gauge. Maybe shift to a lower gear to keep revs up.

Mike
 
My fuel pumped packed up yesterday but I doubt that could have been causing the water temp problems on Friday?(There was no sign of fuel starvation)
 
In my case the water pump is new, shortly after the change it became a bit more obvious. By taking an actual temp reading I took the guess work out of the mix. If the temp was 240*F I would have been a bit more concerned. My radiator is original with close to 190K on it. I will do a flush shortly to see if anything changes. If it moves any higher I'll take another reading, and worry then.
 
Originally Posted By: SteveSRT8
are you guys remembering the fan clutch?

This can cause the symptoms being described as well.


Viscous fan has a slight drag on it and would it not cause problems in stop start traffic rather than high speed?
 
Originally Posted By: SteveSRT8
are you guys remembering the fan clutch?

This can cause the symptoms being described as well.


I'll have another look, I swapped mine out and it didn't help any.
 
There could be cavitation in the pump but I would be very surprised if a medium-duty truck struggles on hills.
 
Definitely not cooling fan/clutch related. When my car had the cooling fan relay problem it would warm up idling and cool down once in motion.

If it is the thermostat, it would be constantly high rather than only on hill climb (non fail safe), or it will be cool below normal when going downhill (fail safe).

It is probably a blocked radiator or water pump, or other things that reduced its efficiency.
 
I think my best bet is to replace the radiator(its 15years old anyway) and I will buy silicone liquid refill tube from toyota to overhaul the viscous coupling fan.
Could there be a blockage in the block?
 
Do you have a real coolant temp gauge?
Most of the later ones are not.
A real temp gauge will show variations all of the time as driving conditions vary.
If you do, you'll find coolant temperature varies a great deal depending upon conditions.
Climbing a hill, for example, requires more power than running on level ground, using more fuel, and producing more waste heat, some of which is resolved into the coolant, so you see a commensurate increase in coolant temperature on the gauge.
If you have a real coolant temp gauge, you may simply be seeing the real increase in coolant temperature, and nothing is amiss.
 
Have you ever done the same pass and it not heat up? Did something change? Im thinking along the lines of what fdcg27 said. My parents had a 83 nissan sentra thats engine was so weak it struggled like crazy going up the mountains in Tennessee and it would heat up just like you are describing. That vehicle was almost brand new. Same thing happened later to their old mercedes diesel. It would heat up climbing these steep mountains. Not overheat but its temp would increase.
 
t-stats can get lazy. buddy's subaru GL was fine in town, rock stable temp but would overtemp at 55, get HOT at 65 and red at 70, come back down in town. changed the stat and it was fine.
 
Status
Not open for further replies.

Similar threads

A
2019 Honda Pilot temp went cold
Replies
10
Views
425
ARB1977
daves87rs
Check gauges on a dying cluster?
Replies
6
Views
359
daves87rs
Twisted1
So I received my replacement bearing from RockAuto
3 4 5
Replies
82
Views
5K
Barkleymut
N
2003 Buick Rendezvoux overheating randomly
Replies
19
Views
2K
super20dan
Nick1994
Grand Cherokee Running Warm Towing
2 3 4
Replies
60
Views
4K
Astro14
Back
Top