why my 305k LC blew up (1 Viewer)

[ponytl]

For the exact same reason my wifes lx470 did the radiator split at the top seam... After my engine install i was down to putting the radiator in and fire'n her up... but being an old dirt racer I wanted to clean the radiator before I reinstalled it... I use the same foaming coil clean&bright I use on A/C coils... amazing how much dirt & bugs wash out of the fins....
anyway I run the hose through the hose connections just to do a quick flush and damn if water doesn't pour out of the top seam... exact same as what caused me to put an engine in my LX470... it was a non factory replacement radiator... but i still had the oem one from the lx470 and that is where it also failed... I once had the same issue on a ford diesel (7.3) and it stopped when I went to a lower pressure radiator cap...

the good news is that this cruiser would still be on the road rack'n up miles if it wasn't for this failure... the bad is the fact that it was blown up is the only reason I got it...

with a catastrophic radiator failure you all but never see the temp go up because there is no coolant around the sending unit to make it register... on race cars we use to install a pressure gage in the coolant loop with a warning light to monitor coolant system pressure for this exact reason....

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[TXLX100]

Sounds about right. Cooling and timing belt components are the only causes for failure I've seen. Everytime I saw a blown radiator, the thermostat was bad. I would think the radiator cap would blow, but I guess it depends on age and condition of radiator. Not to say that is what happened to you.

Easiest fix for the failures I'm aware of are changing out water pump, tensioner, idlers, heater T's and thermostat.

 

[ponytl]

Sounds about right. Cooling and timing belt components are the only causes for failure I've seen. Everytime I saw a blown radiator, the thermostat was bad. I would think the radiator cap would blow, but I guess it depends on age and condition of radiator. Not to say that is what happened to you.

Easiest fix for the failures I'm aware of are changing out water pump, tensioner, idlers, heater T's and thermostat.

if it was the thermostat... it would get hot first which would show on your temp gauge, it should then overcome the radiator cap and have a somewhat controlled loss of coolant... what appears to be happening with these crimped top plastic radiators is that it takes less pressure to blow the radiator apart than it takes to overcome the rated pressure cap... it appears toyota used a 16lb cap I have used upto 22lb caps on a fully brazed or welded radiator, I am not sure what effect age has on these radiators,
with 60% anti freeze the boiling points are as follows

0 pressure 231F 4lbs 241F 8lbs 253F 12lbs 264F 16lbs 273F

going to a 12lb cap I don't believe would be an issue hard to see these engines running over 250 degrees,

I'm thinking it's a radiator issue I believe they are failing at less than 10lbs of pressure...

 

[KraziAzn]

Will a scan gauge help in this situation? If I was reading the oil temp of the engine? Since there is a loss of coolant, the coolant temp won't raise, but the oil temp should go up as the engine gets hotter right?

 

[Rolocado]

And at what point do you replace the thermostat? Just do it at any point as preventative?

 

[KraziAzn]

And at what point do you replace the thermostat? Just do it at any point as preventative?

My original radiator cracked at the top. Now it is slowly leaking out coolant kinda like op. I'm going to replace the thermostat/ radiator/radiator cap all at once. The thermostat and cap are relatively cheap and easy to replace. Potentially it can save me a huge headache down the road.

 

[abuck99]

Will a scan gauge help in this situation? If I was reading the oil temp of the engine? Since there is a loss of coolant, the coolant temp won't raise, but the oil temp should go up as the engine gets hotter right?

No way that I know of to get oil temp to display through Scan Gauge on a 100 series; but if you come up with an X-code please advise. Most likely have to hard wire a sensor to the head and have a gauge in the cabin to get that data.

A sensor in the overflow bottle might help alert for a leak- I believe a leaking cooling system would draw the bottle dry first. In a catastrophic failure it may not alert soon enough though. Flow sensor in-line at the heater T would also alert of lack of coolant flow. Unfortunately I haven't found a reasonably priced plug & play device for monitoring coolant flow.

 

[Greenbean]

I’m gonna say it’s possible but more than likely if you don’t notice the temp rising and then it’s leaking out and there isn’t any flowing past the sending unit for the temp reading, you’d never know it.

I’m not educated on where and how the ECU reads the temp of the coolant, I watch it on my SC2 though and with the trans temp also.

Just like keeping an eye on things I guess.

 

[AimCOtaco]

And at what point do you replace the thermostat? Just do it at any point as preventative?

As needed but most often replaced with a timing belt job every 90k


... I also have not seen a scangauge/oil temp solution but would be glad if an oil temp sensor was already present and could be read.