FJ62's Overheating. Several of us don't know why.

Joined
May 14, 2018
Messages
130
Location
San Francisco Bay Area
Visit site
I also picked up a couple of these. Thermocure

Going to run it with distilled water for a few days as well as the prestone stuff (not at the same time). Seems promising.

EDIT: Some of the reviews for the Thermocure are scary!!! Eep!! Anyone ever use this stuff?
I've been thinking about using thermocure on my 60. I've noticed rust in my coolant. It's not milky suggesting coolant mixed with oil. I haven't seen any scary reviews...just really good reviews. Can you share some of the scary reviews you found? Have you tried the Thermocure since you posted on Monday?
 
Joined
Oct 9, 2015
Messages
317
Location
Truckee, CA
Visit site
I've been thinking about using thermocure on my 60. I've noticed rust in my coolant. It's not milky suggesting coolant mixed with oil. I haven't seen any scary reviews...just really good reviews. Can you share some of the scary reviews you found? Have you tried the Thermocure since you posted on Monday?
Apparently several blown head gaskets... among other issues. It's a small percentage so I'm going to take the risk but it's a bit scary. I've not done it yet. I've been working on my AC system. I might get to it this weekend.

 
Joined
May 14, 2018
Messages
130
Location
San Francisco Bay Area
Visit site
Apparently several blown head gaskets... among other issues. It's a small percentage so I'm going to take the risk but it's a bit scary. I've not done it yet. I've been working on my AC system. I might get to it this weekend.

thanks. my reviews came from google, didn't think about looking at amazon reviews. how are you going to flush out the thermocure? i was thinking of attaching a garden hose to the lower radiator hose and have it come out of the tstat housing (taking the tstat out). i have a new rad i just put in. i kinda want to flush the rad separately bc it's new and knowing i'll be creating a bunch of gunk and debris in the block. and then a final flush with distilled water, then add coolant. curious, if you're doing something similar.
 
Joined
Oct 9, 2015
Messages
317
Location
Truckee, CA
Visit site
thanks. my reviews came from google, didn't think about looking at amazon reviews. how are you going to flush out the thermocure? i was thinking of attaching a garden hose to the lower radiator hose and have it come out of the tstat housing (taking the tstat out). i have a new rad i just put in. i kinda want to flush the rad separately bc it's new and knowing i'll be creating a bunch of gunk and debris in the block. and then a final flush with distilled water, then add coolant. curious, if you're doing something similar.
I have one of those high pressure flushing guns that mixes air in as well. My plan is to pull the rear drain plug out of the block and go to town through the top tstat hose location after pulling the tstat. Then close everything up. Afterwards I plan on running distilled water with a gallon of white vinegar to neautralize the smell of the thermocure.
 

Spook50

My daughter likes Stitch
Supporting Vendor
Joined
Feb 16, 2005
Messages
6,478
Location
Spokane, WA
Visit site
I have one of those high pressure flushing guns that mixes air in as well. My plan is to pull the rear drain plug out of the block and go to town through the top tstat hose location after pulling the tstat. Then close everything up. Afterwards I plan on running distilled water with a gallon of white vinegar to neautralize the smell of the thermocure.
Careful with that vinegar. It's also highly corrosive if you don't get ALL of it out with multiple water flushes. TBH I'm not too keen on the idea of the Thermocure. I'll be doing the Pennzoil twice, then a ton of water, then new water pump, take care of hoses and clamps, then fill with tried and true Toyota Red.
 

MoaByte

SILVER Star
Joined
Dec 13, 2014
Messages
1,512
Location
Moab
Visit site
HCL, or muriatic are just stronger forms of vinegar. It does remove rust. Neutralize with Calcium carbonate, or baking soda. When the bubbles stop, do it one more time. Then flush it with the garden tap.

Rinsing the block doesn't need distilled water, tap water is fine. But dilute full strength coolant with distilled water as it's going to set in your block, head, and radiator for a few years. If you prefer to use pre diluted coolant (50/50), you probably shouldn't try flushing your engine by yourself because you are rich enough to hire a professional and you are better at other things.
 
Joined
Mar 4, 2016
Messages
1,747
Location
Boulder, Co
Visit site
Mine does this as well, but I'm waiting to get a new water pump and replacement hoses so I can do those immediately after a full system flush and see if that makes any difference. Yesterday at ~75 for a long (level) highway stretch my gauge got up to just barely below the overheat point by the time I exited to finish my commute home. Granted it was 113F outside at the time, this is the first time in many years that I've noticed it get that hot. Last summer in the heat it would get warmer than normal, but not as warm as it did yesterday.

This was with my AC off as well, so there wasn't the "pre-warmed" air from the condenser going through the radiator.
Watch your battery when it cools down in the fall...
 
Joined
Oct 9, 2015
Messages
317
Location
Truckee, CA
Visit site
Careful with that vinegar. It's also highly corrosive if you don't get ALL of it out with multiple water flushes. TBH I'm not too keen on the idea of the Thermocure. I'll be doing the Pennzoil twice, then a ton of water, then new water pump, take care of hoses and clamps, then fill with tried and true Toyota Red.

If handled and used properly there is nothing to worry about with vinegar. If I had aluminum in the system I might agree but vinegar is not a long term solution and of course a proper flush is required afterwards. In a cast iron block I don't see any problem. Not sure what you don't like about Thermocure. Could you provide reasoning behind that? I personally haven't used it but it sure does sound good. The vast majority of reviews are positive. The ones that aren't I'm beginning to think the cars were neglected and too far gone. I suppose I'll be the guinea pig and let you all know how it goes. Maybe it fixes my problem. Maybe it doesn't but if it pulls out the rust then at least it's a step in the right direction.

I'm grasping for straws at this point and this one sounds promising. Not getting my hopes up but lets see how it goes.
 

Spook50

My daughter likes Stitch
Supporting Vendor
Joined
Feb 16, 2005
Messages
6,478
Location
Spokane, WA
Visit site
If handled and used properly there is nothing to worry about with vinegar. If I had aluminum in the system I might agree but vinegar is not a long term solution and of course a proper flush is required afterwards. In a cast iron block I don't see any problem. Not sure what you don't like about Thermocure. Could you provide reasoning behind that? I personally haven't used it but it sure does sound good. The vast majority of reviews are positive. The ones that aren't I'm beginning to think the cars were neglected and too far gone. I suppose I'll be the guinea pig and let you all know how it goes. Maybe it fixes my problem. Maybe it doesn't but if it pulls out the rust then at least it's a step in the right direction.

I'm grasping for straws at this point and this one sounds promising. Not getting my hopes up but lets see how it goes.
It is very possible that the cars that reported damage after using Thermocure had other underlying issues that it may have simply uncovered. The problem is though, we don't know for sure. We can assume, yes, but to that effect either conclusion will hold just as much or as little weight as the other. Given how minor my own heat issue is at this point, I venture that if it's just a maintenance issue, the Pennzoil solution will do just fine. This is considering my particular case though. If you do go ahead with the Thermocure, I am curious what your results end up being. If you intend to take samples of the fluid you flush out after you give it a good run through your system, that would be very interesting. I intend to as well when I run the Pennzoil through mine.

@cps432 temps above 110 in this region are very rare, but I have been in them before with no adverse effects to the batteries I was running at the time. Funny enough, the hottest I've ever had my 62 in was in 2009 when there were several days just shy of 120 degrees in Potholes National Park here in WA about 12 years ago while I was camping. I've used AGM batteries for close to 20 years now though, so that could be another reason I've never had any issues aside from age. It's been a good long time since I've dug into the chemistry and makeup of automotive batteries though, so I honestly don't remember much at all of the science behind them beyond what my own experiences have helped me retain.
 
Joined
Mar 4, 2016
Messages
1,747
Location
Boulder, Co
Visit site
It is very possible that the cars that reported damage after using Thermocure had other underlying issues that it may have simply uncovered. The problem is though, we don't know for sure. We can assume, yes, but to that effect either conclusion will hold just as much or as little weight as the other. Given how minor my own heat issue is at this point, I venture that if it's just a maintenance issue, the Pennzoil solution will do just fine. This is considering my particular case though. If you do go ahead with the Thermocure, I am curious what your results end up being. If you intend to take samples of the fluid you flush out after you give it a good run through your system, that would be very interesting. I intend to as well when I run the Pennzoil through mine.

@cps432 temps above 110 in this region are very rare, but I have been in them before with no adverse effects to the batteries I was running at the time. Funny enough, the hottest I've ever had my 62 in was in 2009 when there were several days just shy of 120 degrees in Potholes National Park here in WA about 12 years ago while I was camping. I've used AGM batteries for close to 20 years now though, so that could be another reason I've never had any issues aside from age. It's been a good long time since I've dug into the chemistry and makeup of automotive batteries though, so I honestly don't remember much at all of the science behind them beyond what my own experiences have helped me retain.
I finally bit the bullet on a huge AGM diehard battery this year. It’s a tractor trailer battery and I can run my lights and stereo for an entire weekend with no problems at all. Back when I was using old school batteries I had failure every other year or so. Here in Colorado it doesn’t get gnarly hot too often but it stays very warm in July and August. Warm enough to strain the battery and kill it when the temps drop. Agm is the way to go.
 
Joined
Jun 24, 2013
Messages
70
Location
Clark, Colorado
Visit site
If the engine can keep its temps within its normal operating range when traveling full speed on the freeway on a hot day, then the radiator and water pump and coolant flow would be working as they should.

If the vehicle then pulls off the freeway on that hot day and the temps begin to climb while waiting at a stop light or driving slowly in traffic, that's pretty much normal unless the fan clutch isn't working properly.

The engine is blazing hot while driving fast, way hotter than the coolant gets, so when the vehicle suddenly slows down and drives slow, or waits at a stop light, all that hot metal keeps on dumping heat into the coolant - but the coolant isn't circulating as fast any more and the air flow through the radiator is way way less than when driving 65 mph.

On my 60, I always reved up the throttle a bit with either the choke knob or throttle knob or my foot on the gas pedal to get the RPMs up to maybe 1000 rpm while waiting at a stop light after driving fast. It helps keep the coolant flowing faster and the fan pulling more air so the coolant doesn't get too hot
I don’t drive freeways, and the fastest I go is about 55, because I live in a rural area. But I nevertheless use the same technique to keep my engine cooler when I get in city traffic. The FJ60 is designed to move, not slug around in stop and go traffic.
 
Joined
Sep 20, 2019
Messages
199
Location
Marquette Michigan
Visit site
I don’t drive freeways, and the fastest I go is about 55, because I live in a rural area. But I nevertheless use the same technique to keep my engine cooler when I get in city traffic. The FJ60 is designed to move, not slug around in stop and go traffic.
The 60 was designed for the harshest conditions and has a very robust cooling system. Mine has never been over 1/3 on the gauge and that includes this past weekend of wheeling in the heat, with the AC on for 8 hours averaging about 2 miles an hour, the only air flow through the radiator was from the fan. Normal driving mine sits at 1/4 on the gauge.
 

MoaByte

SILVER Star
Joined
Dec 13, 2014
Messages
1,512
Location
Moab
Visit site
I'll 2nd that. 104°, idling along in 2nd low, AC blasting, MPG doesn't suffer as much as in town driving and runs cool. Worst gas mileage is over 55 or winter driving with long warm ups around town.
Hottest I've seen is 204°, up hill, AC on, towing a 14' trailer.
 

Users who are viewing this thread

Top Bottom