100 Series Overheat (1 Viewer)

[Seattle100]

After about 5 miles on the highway, the rad cap spewed boiling fluid all over the windshield and temp gauge was pegged at max. I pulled over, cooled off, and limped home.

I figure it's the T-stat or the water pump, as the fans all seem to work, and I would think the fan clutch would be cooler at speed than idle, no? No obvious leaks, except for the red geyser from the radiator. I did the coolant T's last year, with all new fluid at that time.

But here's what's got me scratching my head: I turned the interior heater to full hot as soon as this happened, but the air coming through was still cold. I would have expected that to have gotten hot right away. Does this mean that the water pump failed? I really hope not...

I'm grabbing a T-stat, a rad cap, and gasket on my way home tonight. Let me know if I should be thinking about anything else.

Thanks in advance!

 

[suprarx7nut]

Lack of heat in the HVAC system combined with overheating and erupting radiator mean a blown head gasket in my experience. Pretty rare for a 2UZ, but that's my initial thought.

All out water pump failure is pretty rare, but maybe that's a part of the problem.

Let us know how it goes!

 

[Seattle100]

I would have thought a blown head gasket would have lead to the white smoke exhaust as I limped home, no?

I've never blown a head gasket (despite many 3vze engines), so I'm not entirely familiar with the symptoms, or testing. How would I test that? Oil in coolant, or the other way around?

If the T-stat stuck closed, but the water pump still functions, I should get heat in the HVAC, correct?

 

[suprarx7nut]

I would have thought a blown head gasket would have lead to the white smoke exhaust as I limped home, no?

I've never blown a head gasket (despite many 3vze engines), so I'm not entirely familiar with the symptoms, or testing. How would I test that? Oil in coolant, or the other way around?

If the T-stat stuck closed, but the water pump still functions, I should get heat in the HVAC, correct?

Depends how it blows, but yeah normally you'd notice some smoke/steam in the exhaust. It's possible to blow the seal between the combustion cylinder and the coolant jacket and just have a ton of combustion gas in the coolant before you notice much steam in the exhaust.

A compression test would be one of my first diagnostic tools here. If you pass compression then you can pretty much rule out BHG and focus on the coolant system side of things (t-stat, water pump, etc...).

Are any of the coolant system items overdue for maintenance? How old is the radiator?

 

[Seattle100]

I'm at 195k.

Tstat was done at 132 according to previous owner.

I did Coolant T's with full fluid change at 183.

Timing belt done at 85k (yes, I know I'm due); and I assume they did the water pump at the same time.

Radiator is likely original. What's the recommended life of this radiator? I thought they went forever if you paid for the toyo red coolant?

 

[suprarx7nut]

The radiator is a concern to me because they can become clogged with debris and build up. That might explain your overheat and pressure build up, but I'm just fishing.

If you're already due to timing belt, I would do a compression test and if that passes, I'd jump into a full timing belt job. If the rad is original and showing plastic stress cracks I'd also replace the radiator with a Denso unit. It might be a contributor to the problem and a $166 radiator is a hell of a lot less expensive than a new motor.

 

[Seattle100]

I'm looking to get the truck running for another couple of months before I dig into the timing belt job. I'll do the radiator then for sure. If nothing else, it'll give me more room .

I'll let you know how it goes.

 

[2001LC]

Cabin heat not working (blowing hot) is most often a sign of low coolant. This is very common after a coolant system flush. The radiator level must be checked after and 8 hour cool down, then reservoir level checked. Do this daily until radiator will not except any more coolant. Air in coolant system, than reservoir will not function as designed.

Also one issue I've been see lately, is reservoir hose not inserted properly. The hose get hung up on shelf in reservoir, then coolant system sucks air while cooling. Yet reservoir level near max after cool down looks good.

Typically a weak thermostat and engine runs cool. A stuck thermostat can result in overheating, but this is not common in properly flush system.

Weak radiator cap can cause issue where reservoir is not functioning as designed.

Also the fins of our radiators are getting clogged over time/miles. By removing the skid plate you can see between engine cooling radiator and condenser (AC radiator). I find them clogged very often.

Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

forum.ih8mud.com

If water pump bad it will leak badly in most cases. You'd see this at weep hole and sides of timing belt cover.

Head gasket leak or wrapped heads is most often due to overheating. They usually leak around outside of heads(s). Many test for this starting with visually inspecting.

Compress will be bad from warped head. Typical two cylinders next to each other are down to 40PSI

Head gasket leaks is easy to see.

Leaks between cylinder and Coolant often gets in oil.

Warped head apparent at head gaskets.

 

[Seattle100]

Thanks for all the info. Really helpful.

It's been a year since I replaced the coolant, so I don't think this was due to a recent flush. It's possible there's air in the system, but I didn't put it in there recently. The overflow tank was at about 1/2 full after dumping coolant out the top.

I'm going for the tstat and gasket tonight (because it's cheap and easy) and see how that goes. If the problem isn't solved, I'll run the compression test, and if I pass, will get the radiator, timing belt, and water pump on order.

I don't want to even think about what happens if I fail compression...

 

[atnolan94]

It sounds like your radiator burst to me. I'm not saying this is definitely the case but is it holding coolant?

 

[flintknapper]

Thanks for all the info. Really helpful.

It's been a year since I replaced the coolant, so I don't think this was due to a recent flush. It's possible there's air in the system, but I didn't put it in there recently. The overflow tank was at about 1/2 full after dumping coolant out the top.

I'm going for the tstat and gasket tonight (because it's cheap and easy) and see how that goes. If the problem isn't solved, I'll run the compression test, and if I pass, will get the radiator, timing belt, and water pump on order.

I don't want to even think about what happens if I fail compression...

Definitely check your Tstat...I had a new OEM (less than a year old) fail (stuck closed) on my Wife's LX470. Overheated in the same fashion you described.

Thankfully, just reaching that point at the end of her 20 minute drive into work. No damage to engine, but the 2UZ does not like to be overheated. The engines usually run remarkably cool and are also very easy on engine oil.
Hope the issue with yours is something simple.

Flint.

 

[Seattle100]

Andrew wins!

I topped up the radiator first thing last night, and it immediately leaked on the driveway. I think the geyser was a blown radiator, not the cap.

Now, what caused the radiator to blow is another question...

I pulled the radiator, and have a new one on order. I put the new t-stat in for good measure. I'm hoping to be up and running tonight, and I'm really hoping there was no damage from the brief overheat.

What engine damage would you expect to see from a brief overheat? Head gasket?

 

[94SRUNNER]

Do you have a picture of the blown radiator? If it is original like you mention in a post above, they do break down with age and fail. Typically a sign of an older radiator is the plastic begins to turn brown. There are lots of threads on Mud documenting this.

 

[OEMGUY0720]

A possible warped head gasket. Check also the area where the intake manifold meets the head and see if there’s any seepage of coolant there. The 2UZ have 4 water bypass gaskets (2 in the front and 2 in the rear), those leak out too and wouldn’t hurt to check.

 

[atnolan94]

Andrew wins!

I topped up the radiator first thing last night, and it immediately leaked on the driveway. I think the geyser was a blown radiator, not the cap.

Now, what caused the radiator to blow is another question...

I pulled the radiator, and have a new one on order. I put the new t-stat in for good measure. I'm hoping to be up and running tonight, and I'm really hoping there was no damage from the brief overheat.

What engine damage would you expect to see from a brief overheat? Head gasket?

My radiator burst and as long as the t stat was closed it didn’t leak. Not ideal but likely ok. These are resilient engines. I drove like a mile on it and no issues last 20k miles after new rad.

Throw in a new rad and keep on trucking.

Also not to rub in your woes, but WINNER WINNER CHICKEN DINNER haha. Best of luck.

 

[atnolan94]

FYI they have plastic caps and literally just get old and burst from pressure. Wouldn’t panic about determining cause. It is just not unusual at all.

 

[Seattle100]

The top hose nipple was pretty crumbly, similar to the hot heater T that failed last year. The leak appears to be the top cap of the rad. I didn't look very closely at exactly where yet, but it sounds consistent with the plastic getting old.

 

[suprarx7nut]

The top hose nipple was pretty crumbly, similar to the hot heater T that failed last year. The leak appears to be the top cap of the rad. I didn't look very closely at exactly where yet, but it sounds consistent with the plastic getting old.

Yup, it's a wear item at some point. The plastic won't last forever. Sounds like yours just finally gave up. Like Andrew said, install a new one and move on. Glad it's not a BHG!

 

[flintknapper]

FYI they have plastic caps and literally just get old and burst from pressure. Wouldn’t panic about determining cause. It is just not unusual at all.

^^^^^
Not mine....but you get the idea what is possible.

 

[Seattle100]

ARRRRGGHHHh

Radiator in, fluid topped up, and now I'm leaking from what I believe to be the water pump. THat's the one on drivers side, driven by the serp belt, right?

So it seems like I'm going all in tonight. Gonna tear it all down and hope my dealer has my parts in the AM....

Anything else I should be looking at while I'm in there?