Upper Radiator hose ..... blown!

[Robert LaDuke]

I was driving yesterday and started seeing steam coming out from under the hood while stopped at a light. The Toyota temp gauge was in the normal position. Pulled over and popped the hood. Huge tear in the side of the upper radiator hose. Wondering what caused this? What should i check? Thermostat? Could it be that the hose was just worn out? Or is this the symptom of a deeper problem?

1978 FJ 40

 

[DSRTRDR]

check water pump and fan clutch

 

[Living in the Past]

Only thing other than a worn out hose that would cause it to tear would be a plugged radiator. If that was the case your engine should have been running hot before it blew. The lower hose is the suction to the water pump and really no way for it over pressurize. If anything you want to check would be the radiator cap. That can cause the pressure to go up in the whole system if your low on coolant and you start to over heat.

 

[Robert LaDuke]

Thanks for the replies. The truck has about 3000 miles on it since it was restored...... but that was ten years ago! All the hoses were new and a new radiator and cap.
I'll try checking the water pump and clutch.
Pretty sure the stock temp gauge is not working as well as it should be. It was showing normal temperature as I was trying to get off the road driving in a cloud of steam!

Any other ideas? Thank you so much.

Bob

 

[Living in the Past]

Are you saying you just replaced the hoses and radiator cap? The hoses are a age thing as much as use. Ten years is not new anymore. If the vehicle sat for long periods during that time the top hose will be the first place to be empty while means dry, so it will age faster. The top radiator has the coolant flowing from the block to the radiator. Bad thermostat would cause lower pressure in that hose not higher. Before that hose should blow the radiator cap should release pressure. Even on plugged radiator the cap to release pressure. With a bad fan clutch or water pump the hose shouldn't blow. The radiator cap is the safety for the cooling system.

 

[Robert LaDuke]

Are you saying you just replaced the hoses and radiator cap? The hoses are a age thing as much as use. Ten years is not new anymore. If the vehicle sat for long periods during that time the top hose will be the first place to be empty while means dry, so it will age faster. The top radiator has the coolant flowing from the block to the radiator. Bad thermostat would cause lower pressure in that hose not higher. Before that hose should blow the radiator cap should release pressure. Even on plugged radiator the cap to release pressure. With a bad fan clutch or water pump the hose shouldn't blow. The radiator cap is the safety for the cooling system.

Thank you . The hoses and radiator were new at the time of resto. But that was 10 years ago. Not a lot of driving time on them but 10 years of mostly parked time. I tried to use OEM whenever possible on my truck but i seem to recall the hoses were from CCOT. I'm hoping the problem is just an old hose. I have new on order. Thanks for the insight! i appreciate it.
Bob

 

[Robert LaDuke]

Oh.... I will try a new radiator cap also. Thanks
The cap was dry ... no pressure being released at all. The steam was pouring out of the tear in the side of the upper radiator hose.

 

[lostmarbles]

No reason to suspect anything else is wrong besides the split radiator hose IMO.

Maybe the hose was defective? (It does happen, even with genuine Toyota items.)

But at 10 years old and with this having happened, I'd replace both top and bottom radiator hoses (together with adding a fresh quality coolant mix using demineralised water).

And if the remaining coolant looked at all dirty/rusty, I'd probably give it all a good flush at the same time.



PS. Leaking hot coolant will "steam" even if it is not boiling (and your temp gauge staying in the "normal range" suggests it wasn't abnormally hot).

You can tell if your water pump is OK or not by checking for abnormal play in the bearings.

 

[Robert LaDuke]

No reason to suspect anything else is wrong besides the split radiator hose IMO.

Maybe the hose was defective? (It does happen, even with genuine Toyota items.)

But at 10 years old and with this having happened, I'd replace both top and bottom radiator hoses (together with adding a fresh quality coolant mix using demineralised water).

And if the remaining coolant looked at all dirty/rusty, I'd probably give it all a good flush at the same time.



PS. Leaking hot coolant will "steam" even if it is not boiling (and your temp gauge staying in the "normal range" suggests it wasn't abnormally hot).

You can tell if your water pump is OK or not by checking for abnormal play in the bearings.

Thanks Tom,
I've ordered a complete set of new hoses. Figured I would do all of them at once.
I'm not feeling any play in the water pump. I think it is probably not the culprit in this case.
Thought i would try a new radiator cap as was suggested by Living in The Past.
So you think the temp gauge may not be faulty? I hope you are correct. I would like to think i didn't overheat my engine.
Thanks for the help!
Bob

 

[Living in the Past]

Oh.... I will try a new radiator cap also. Thanks
The cap was dry ... no pressure being released at all. The steam was pouring out of the tear in the side of the upper radiator hose.

Your water heater has a T&P relief (temperater and pressure). Your radiator cap is pressure only. Once the hose burst you wouldn't have any pressure in radiator so even a good cap wouldn't leaking.

Tom made a good call on the demineralised water. I use a 50/50 mix of antifreeze and distilled water. Here in AZ our tap water is full of minerials.

 

[kurtnkegger]

I ordered CCOT hoses, that were the WORST quality hoses I have seen. They literally fell apart in a couple of years. Ordered my new hoses from NAPA (I read they were as good as OEM), and won't ever order hoses from CCOT again. I wouldn't look any further than the purchase place for any problems...

YMMV

 

[Robert LaDuke]

Your water heater has a T&P relief (temperater and pressure). Your radiator cap is pressure only. Once the hose burst you wouldn't have any pressure in radiator so even a good cap wouldn't leaking.

Tom made a good call on the demineralised water. I use a 50/50 mix of antifreeze and distilled water. Here in AZ our tap water is full of minerials.

So it looks like I may have a bad hose and nothing more.
I use the same mixture of 50/50 .... distilled and antifreeze. The tap water here in CA will create stalagmites in the radiator!

 

[Robert LaDuke]

I also noticed that the overflow bottle was empty. If I were boiling and building pressure, would this bottle be empty? Or is it more likely the bottle was empty because i was losing all my fluid out the tear in the hose ?

 

[Living in the Past]

I also noticed that the overflow bottle was empty. If I were boiling and building pressure, would this bottle be empty? Or is it more likely the bottle was empty because i was losing all my fluid out the tear in the hose ?

On a full system it's normal for the overflow to have some coolant in it. By design as the engine warms up some coolant will go into the bottle. As it cools after being shut off the coolant will be drawn back into the system on a properly working radiator cap. If I didn't replace the cap I would keep a eye on it to make sure it'a working as it's suppose to.

 

[lostmarbles]

I also noticed that the overflow bottle was empty. If I were boiling and building pressure, would this bottle be empty? Or is it more likely the bottle was empty because i was losing all my fluid out the tear in the hose ?

Hi again Bob.

Lifting the bonnet/hood every so often and taking a look inside should be normal procedure with these old girls.

And checking to see you have an acceptable level of coolant in the reservoir/overflow bottle at all times should be automatic whenever the hood is lifted.

Unfortunately a leak up high (like on the top radiator hose) tends to stop the radiator from sucking back (from the reservoir) coolant that it expelled on warm-up. (So when looking at the level in the reservoir you tend you think you're OK on coolant level but the level inside the radiator has actually fallen because air has been sucked in through the high-level leak.)

So what I'm saying is - The leak on your upper hose shouldn't have been capable of draining your reservoir. (Only leaks in the lower 2/3rds of the coolant system will drain the reservoir from my experience.)

So the absence of fluid in your reservoir is a fresh cause for concern in my opinion because it suggests to me that you may have a leak somewhere lower down too (and if this had been neglected it may indeed have caused your top hose to rupture from an over-pressure/overheating incident).

On a full system it's normal for the overflow to have some coolant in it. By design as the engine warms up some coolant will go into the bottle. As it cools after being shut off the coolant will be drawn back into the system on a properly working radiator cap. If I didn't replace the cap I would keep a eye on it to make sure it'a working as it's suppose to.

I agree.

The absence of coolant in the reservoir suggest to me that another leak may be lurking somewhere.

 

[DSRTRDR]

It was showing normal temperature as I was trying to get off the road driving in a cloud of steam!

so was mine when the water pump grenaded itself one mile before the highway off ramp - temp gauge showed fine until the traffic light at the end of the ramp, where steam came out the vents and a coolant lake accumulated under the truck

on the other hand, when the fan clutch crapped out recently, I could see the temperature gauge needle slowly going past the second peg while driving 65 mph on the highway

I guess what I am saying is that you need to check ALL components of your coolant system

 

[Anvil]

X2, CCOT radiator hoses suck! I'm now replacing mine after just 2 years. I have bought many parts from them, and most have worked well. But not the hoses...

 

[Robert LaDuke]

Thanks everbody for the replies and advice.
I will check things out carefully.
Claudia, I will be checking the water pump nd fan clutch just to be sure. I have a brand new OEM water pump and clutch sitting on a shelf waiting for the day it is needed!

Tom, I restored this truck over a three year period beginning in 2001. I think i spend more time under the hood checking fluids and fiddling with stuff than i do driving it! Thanks for your advice and suggestions. I'm hoping for the best.... a bad hose would be ideal.

 

[Robert LaDuke]

X2, CCOT radiator hoses suck! I'm now replacing mine after just 2 years. I have bought many parts from them, and most have worked well. But not the hoses...

Thanks for the input Anvil. I removed the hose from the radiator. It appears fine on the outside ( except where it split open) Not so good on the inside. The inner walls of the hose appear to be cracked and coming apart. New hoses are on their way!

 

[cuencanolenny]

In the process of replacing my radiator and water pump and noticed that one of my new hoses (at the water pump to the "pipe") has a perforation in it. Hasn't leaked, yet, but rubber never heals itself. These hoses are the "kit" from CCOT. So I will find a replacement for it today. I am in Ecuador and Lord only knows what I will find, but you folks in the USA have access to Gates Hoses and Belts and in my many years of wrenching I find them to be the best. Sort of like Fel-Pro are the best gaskets, Clevite are the best bearings for race engines but Federal Mogul are the best for street engines due to the softer bearing material, Melling are the best pumps.