Radiator blown while car had been off two days

Hi guys, good to be part of the community.
Unluckily my first thread is not a nice one: this seems a difficult one to solve. In brief:
- Ten days ago I drove a 40km corrugated dirt road forth and back. Old radiator (aftermarket, fairly consumed) cracked once I turned the car off. Found dirt (oxid)in the reservoir.
- 5 days ago replaced with new radiator (aftermarket). Cracked again 2 days later in the same spot (bottom right corner facing the radiator), again while the car had been off overnight. Thought was a faulty one and I had a refund.
- Bought ONE MORE RADIATOR. Today, after 2 days without turning the car on, it seems to have broken again in the same spot. I had opened the cap to avoid pressure accumulating and disconnected the battery, but it seems to have failed once again in the very same spot. What a nightmare.

What is going on?? How could the radiator repeatedly crack in the same spot after being cold for two days???

I have a 2001 Japanese 4Runner with KZ185 engine, a 3.0 TD EFI with 340.000km.

Any help would be kindly appreciated.

 

It's possible something is blocked. The water pump keeps pumping and pressure builds. You turn the car off and the pressure can't be relieved and the radiator cracks at a weak point

This is just speculation on my part, as I am not an expert on coolant systems.

You may want to message The Car Care Nut on YouTube. He is an expert Toyota mechanic.

 

The other thing I would be curious about is the mounting of the radiator itself. Could something be tweaked just enough...

 

I see the coolant but I don't see the crack itself. Can you mark it? Can it be the radiator is OK and the leak is from the upper hose or ...?

If it is really the radiator, I was thinking pressure buildup either due to blockage (like the response from Cowboy59) or even a blown head gasket but your entry states that the third radiator failed after two days without running the engine so these cannot be. Not sure what type of a coolant you're using but the coolant can freeze but you are in Florida so this cannot be either. This may just be a coincidence but perhaps the third radiator had a latent condition that may not have been obvious when it was manufactured.

 

One other thing I have seen, the hoses can be a real pain to slide on to the new radiator fittings. I have seen someone crack a hose nipple while manipulating the hose to work it on to the radiator. In the past, I have used a very thin layer of silicone dialectric compound inside of the hoses to help them slip on, just because it was something I had on hand. Dish soap also works.

 

If it were me, I'd just bite the bullet and buy a TOYOTA radiator.

Aftermarket parts are pure trash. There are tons of Mechanic threads where they have to order MORE THAN half a dozen of the same part from different places to get one that isn't defective. There have been entire shipments of parts to the same store and every last one was visibly defective. Big box autoparts stores also get their parts from the same suppliers so just going across the street just gets you the same broken part. There seriously needs to be a class action lawsuit on this shit.

 

Thank you all for the answers and suggestions! I would have rather talked with you guys about something more pleasant, but here I am sweating to solve the issue. Fun fact for all: I am an Italian working with NGOs and I now live, and write from, Paraguay in South America. I purchased the vehicle 3 months ago so there’s few things coming up now after the first trips to remote indigenous communities. I’ll answer one by one to the suggestions.

 

Welcome to the forum. BTW your English is far superior to my Italian

 

The fact that you aren't saying you are experiencing overheating, makes me think it's not a blockage.

I also agree with Ahdofu...make sure you are not leaking somewhere higher. It's very possible you have a leak under a hose and it is running down to the corner.

 

Sorry guys I actually wanted to take more time to answer one by one, but I’ve been summoned up for another trip towards the border with Bolivia. This time we go with the NGO’s truck luckily.

The most interesting clue is that 3 radiators were bugged in the same spot, all 3 of them while the car was off. No overheating experienced at any moment.
I managed to get a refund for the second last, and an exchange for the last, so now I have a 4th radiator which I’m about to install. I wish I could afford the original one, but here in Paraguay it’s about 1100$ at the Toyota dealer. The after make I’m putting on is 150$. Of course there will be difference in car but a) I paid the whole car 7000$ so paying 1100$ for the radiator only at this stage seems unbalanced b) I want to solve the issue first, then I may replace with the original one later one.

Anyway I’m leaving the car to my thrusted mechanic, which will check thermostat, water pump and head. I will share what he’s found in 2-3 days. I’ll leave you with a pic of the truck so that I can kind of complete my presentation to the group. Again, I’m Matteo Fabi, an Italian freelance photographer now living in Paraguay, after 7 years throughout England, Australia and New Zealand (hence the fair English). Thanks to all who have dropped a comment of suggestion.

 

I ditto these comments …. I once had a support bracket that the fan blades would hit in turn pecking holes on my radiator (old straight 6 Ford F100). Other than that it has always been the weep hole on my water pumps that leak. Putting plastic thermostat housings on aluminum water pumps was never a great idea. Keep us posted as to what you find out.

 

That’s the 3rd radiator to fail, the one we just removed. It was definitely another crack in the bottom corner, and a little in the middle too. This happened two days after I hadn’t had the car running. I just checked the cap and the reservoir and two hours later started leaking from the radiator. Mystery.
Anyway there’s a lot of oxide into the pipes, there must be something clogged. Quite likely previos owner was filling with water. I’ll’ share with you the results of the inspection

 

I am inclined to say that if you have not already installed the 4th radiator, just fill it up and wait for two days before installing it. If you believe there are sediments in the cooling circuit, you should also do a complete engine coolant flush too. One other thought. Does the diesel engine have its own spec radiator or were you using what might have been available in the aftermarket?

 

UPDATE

It was indeed a clogged thermostat, now my mechanic is doing a complete flush as you suggest in this very moment. It is an aftermarket radiator but specific for 3rd gen 4Runner with manual transmission.

My mechanic also suggests to “leave open” the thermostat, I understand bypassing it, since in Paraguay temperatures hardly go below 15 degrees throughout the year. What do you guys suggest about this? Could it affect the vehicle in any other way or as he says the thermostat finds its meaning only in cold climate?

 

It is good that you've found an issue but this does not explain why the last radiator failed after two days without running the engine. As for the thermostat itself, I suggest that you do not leave it out. The engine needs to run at a certain temperature range and the thermostat acts as a regulator in the circuit. As for the aftermarket radiator, is the 3rd gen version that you have gotten, the same as the one for a diesel?

 

Mine is indeed a Diesel engine, it’s imported from Japan, the KN185 3.0 TDI EFI.
Here in Paraguay is not as easy as in the US to find parts but I’ll look for a new thermostat then.

 

I think Cowboy59 was right. Although my understanding of the mechanics of the vehicle doesn’t go that far, it seems plausible that the thermostat acted as a blockage and the water pump kept building pressure until the radiator broke, although it had been off for a while. What do you guys think about that? Could it be a likely scenario?

 

I can’t help picture all the the Toyota p/u trucks that are still going strong in some of the 3rd world countries that have no way of getting replacement parts. So my thought is run it for now full open w/o a thermostat and as soon as you get a replacement, then install the thermostat. PLEASE NOTE*. I AM NOT A MECHANIC, also I am picturing you running just water as a coolant for now and doubt that it’s distilled so I think a temporary bush fix is acceptable.

 

Thanks for you opinion anyway, every suggestion matters and of course ain’t easy to figure problems out of a forum, about a car in another continent. Indeed here the market is fair, just not abundant as in the US of course, although I understand the majority of you has the US V6 version of the engine to look after. Let’s say perhaps I can contribute some variety with my exotic 4Runner, writing from an exotic country. The opinions of you all surely count even more to me; I appreciate being helped with figuring some things out.
The funny thing I found here is having probably to have to deal with the slackest Toyota official dealer worldwide. It doesn’t really stand for the famous Toyota efficiency, to say it lightly. I can’t get a quote neither by phone not by any other way so I will have to go myself to the dealer to look for and eventually buy the thermostat. I found it aftermarket for 15$ but I won’t save on this one.
The car by now runs though, I had a complete flush of the cooling system and replaced the pipes too. It was the previous owner, not me, to fill up with water and loads of oxide sludge had build up as a consequence.

 

I am glad to read that all is well now. I go by the adage in Transporter "Take care of the car and the car will take care you". Looks like you'll be doing just that.
Happy Thanksgiving everyone