Heater hose failed on interstate (1 Viewer)

[Plains Cruiser]

Yesterday while driving to a neighboring town I looked down at the temperature gauge and saw it was above 50%. I kept me eyes on it and within several seconds it started to climb higher. I instantly looked for an exit and maybe drove a quarter mile until a pull off and turned off the engine. The gauge didn’t get into red and I waited about 10 minutes before relocating from the exit ramp to a nearby gas station. The temp started at 50% at startup and then raised high again. I popped the hood at the gas station and a small amount of steam came off the engine.

After the radiator cooled I popped the cap and put in around 200 ounces of water (it was totally empty) to help move between the AAA truck and shop, where it’s at now with a Witts’ End kit ready to go.

How likely is it that my head gasket or other internals are now compromised? 190k miles, 1994 FZJ80. I feel lucky I caught the temp raising and wasn’t alerted of a problem by a windshield full of smoke as I drove down the interstate.

 

[Kernal]

Need more information; do you see coolant/water dripping out on the ground?
If so, what side, front of engine, rear, etc??

Also get a bright flashlight and check all the coolant hoses, top and bottom radiator hoses, heater hoses near the firewall and especially look in via the left front wheel well above and inboard of the starter (you'll have to remove or pull to one side the rubber curtains); do you see any staining from chronic leaks on the side of the engine block?

Also check the radiator itself for leaks.

 

[Plains Cruiser]

Need more information; do you see coolant/water dripping out on the ground?
If so, what side, front of engine, rear, etc??

Also get a bright flashlight and check all the coolant hoses, top and bottom radiator hoses, heater hoses near the firewall and especially look in via the left front wheel well above and inboard of the starter (you'll have to remove or pull to one side the rubber curtains); do you see any staining from chronic leaks on the side of the engine block?

Also check the radiator itself for leaks.

I lost all coolant and it definitely came from the PHH. Red Toyota coolant was even dripping from my trailer hitch. All other hoses and the radiator appeared fine. I did get new upper and lower radiator hose and a coolant flush about 2 weeks ago and this was the first longer drive besides a couple of short around town drives. (Would the pressurized coolant flushing system have killed an already failing phh?) The truck is sitting at a shop about an hour away from my home at the moment so I can’t verify the staining right now.

 

[Kernal]

If the flush was used with a garden hose wide open, IMHO yes the pressure could cause a weak/failing PHH to burst, but it was going to burst anyway, assuming that's what you find, an old ruptured PHH.

I would request that the mechanic use GATES GREENSTRIPE heater hose (5/8") and Breeze constant torque clamps, not generic cheapo clamps.
O'Reillys sells the Greenstripe, you may have to call around for the Breeze Constant torque clamps; NAPA may have them (or a Chynna ripoff copy).

If your mechanic can't get those parts for you then get them yourself and bring them to his shop. It does make a difference.

There have been many threads on replacing the PHH, is your mechanic familiar with this job, working on 80 series??

 

[Plains Cruiser]

If the flush was used with a garden hose wide open, IMHO yes the pressure could cause a weak/failing PHH to burst, but it was going to burst anyway, assuming that's what you find, an old ruptured PHH.

I would request that the mechanic use GATES GREENSTRIPE heater hose (5/8") and Breeze constant torque clamps, not generic cheapo clamps.
O'Reillys sells the Greenstripe, you may have to call around for the Breeze Constant torque clamps; NAPA may have them (or a Chynna ripoff copy).

If your mechanic can't get those parts for you then get them yourself and bring them to his shop. It does make a difference.

There have been many threads on replacing the PHH, is your mechanic familiar with this job, workign on 80 series??

Thank you! Appreciate the help.

Thankfully my mechanic is a local land cruiser wizard and has done the phh before. I gave him the Witts’ End kit (hose and clamps).

Should I be worried about damage done by the overheating?

 

[aclos3]

Thank you! Appreciate the help.

Thankfully my mechanic is a local land cruiser wizard and has done the phh before. I gave him the Witts’ End kit (hose and clamps).

Should I be worried about damage done by the overheating?

From your description, it sounds like you caught it in time and I doubt you have done head, block or HG damage, but you should express your concern to your LC mechanic and see what he thinks.

I had a similar failure of both the bypass (head to throttle body) and PHH occur while towing across the country along I-90. I caught both failures before significant overheating (gauge never higher than just a tad over halfway and never blew the radiator cap). The bypass hose was bad enough to require immediate attention, but the PHH was slow enough that I was able to nurse it along for 1000 miles by adding coolant/water (about 1 gallon per 100 miles), watching my OBD II temp gauge like a hawk and taking things very slowly up hills (like 20mph up the continental divide). While this was far from ideal, the truck has been fine the last 5 years and I've replaced every bit of the cooling system now.

 

[effjay80]

Maybe do a quick oil change and send a sample for analysis to Blackstone Labs? For $30 might give you some info or piece of mind.

Hope all okay.

 

[tman2891]

I had a very similar situation. I replaced all major coolant lines, but left the PHH because a PO had bypassed and the line still looked good (and perhaps some laziness). After a few drives around town I felt confident with it, so it took it 1.5 hours away. The trip there went fine, but the PHH gave way half an hour from home. I noticed the temp spike on a OBD2 scanner so caught it before the dash gauge spiked thankfully. I saw the temps get up to 215 at its peak. Once I got it back and began investigating I found that the lower portion of the PHH was in bad shape. My thought is that the new hoses added enough pressure to blow out the weak older rubber. 2500 more miles on it since then and no signs of continued issues thankfully.

 

[BILT4ME]

Thank you! Appreciate the help.

Thankfully my mechanic is a local land cruiser wizard and has done the phh before. I gave him the Witts’ End kit (hose and clamps).

Should I be worried about damage done by the overheating?

I would put in a new PHH, flush the system, get the coolant dialed in properly, and drive it.
Monitor the temps, the oil, and the cooling system.

If you don't have a UltraGauge (OBD2 monitor) or a ScanGauge or a way to monitor it if you're OBD1, then I suggest you figure out that avenue or add extra gauges to monitor. (You don't state what year your truck is)

You'll never feel 100% comfortable until you get miles on it.

I exploded a radiator at 215K, and the HG had been done at 145K. I was ultra-worried about it blowing the HG again, so I put it all back together, then watched the temps, oil, and coolant. I send every other oil change to Blackstone Labs just to stay on top of it.

I am now at 327K and had no issues from that event. I just went through my 100K PM and replaced 100% of my coolant hoses and flushed the cooling system, so I'm good for another 100K.

 

[gummycarbs]

Breeze constant torque clamps

Constant-torque clamps are completely unnecessary unless you're experiencing leakage in extreme cold temperatures.

 

[Plains Cruiser]

As an update - it actually was NOT the PHH but another line that comes off the block nearby. My mechanic says the PHH has already been replaced by a PO and if he had to guess, someone knocked this line when replacing the other. He hasn't seen this one fail before.

 

[LongDuck]

You say it was never in the red, and that's a good indicator that it'll probably be fine once you replace the coolant with the proper Toyota Red and burp the system. When you top off the coolant, recognize that it's going to take a few heating and cooling cycles to get he air bubbles out of it, and in the meantime, you might get some temp weirdness and possibly some coolant overflow from the bottle. Keep in mind that the overflow running out (*aka puking) proves that the vent and capture systems are working, which is important. When it cools, it sucks the overflow bottle down to replace that volume, and after a few times, all of the bubbles will be forced out, and it'll behave.

I relate that when I overheated my engine BUT GOOD, it was going uphill at a crawl in 117F temps trying to keep up with friends and I had my foot in it way too long. It was in the red until I got on flat ground and started to build speed and airflow in the front end, and then the radiator blew up - as in, exploded. It bent the hood up at both corners from the top tank exploding, and afterward, I found the radiator cap had welded itself to the radiator fill neck over time, preventing inflow and outflow, likely leading to my coolant weaknesses.

Point being, I tried HARD to overheat this engine, and succeeded out of my own stupidity. I pushed under the worst circumstances, and ended up with piston slap on #3, which was bearable, and probably could have been limped along. The head gasket was fine, and 50k miles were on it since PM'd. New Rad, Cap, Hoses, Thermostat and Waterpump, and an oil change, and though it ran fine, that's when I noticed the knocking...

When you get it back, listen for weird noises from the block. Watch your coolant level like a hawk, and watch for slimy steam out of the exhaust. If all sounds good, you're likely fine for the long haul. Good that you didn't push it, pulled over immediately, and got it shut down quickly to prevent damage.

Put some miles on it around town, be sure the coolant burps the bubbles and don't sweat it,

 

[bpenn1980]

Not to be a dooms day guy, but the temp sensor and PHH are at the same level on the head iirc. If the PHH dumped (or the little one next to it) enough to empty the radiator isnt there a possibility that the head temp sensor wasnt submerged in circulating coolant and therefore the gauge didnt accurately reflect the actual temp?

Sorry, I was just thinking about all this stuff since I just put an aftermarket sensor on which doesnt go into coolant and I was thinking about pros/cons.

That said, this is all speculation, so agree with get it fixed, then listen/watch for problems. Hopefully all is good.

 

[Kernal]

So the hose that leaked was the smaller diameter bypass hose that runs up to the throttle body??

 

[bpenn1980]

So the hose that leaked was the smaller diameter bypass hose that runs up to the throttle body??

I'm guessing, but I think it is the only one that would be disturbed while doing the PHH.

 

[Plains Cruiser]

So the hose that leaked was the smaller diameter bypass hose that runs up to the throttle body??

I'm guessing, but I think it is the only one that would be disturbed while doing the PHH.

Yep that’s the one. My mechanic is going to replace all 4 bypass hoses while it’s empty.

 

[aclos3]

I'm guessing, but I think it is the only one that would be disturbed while doing the PHH.

That is the the that got me. 20 year old hoses at the time and that throttle body bypass hose failed first and a lot worse than the PHH.

 

[effjay80]

I'm on my last set of replacement hoses - I think. Are these the ones in question back below the throttle body?

 

[mingles]

Yes. 16261-66040: WATER BYPASS HOSE, NO. 1 is the one that gets bumped doing the PHH and is a PITA to do with the throttle body on.

Circled below.

 

[bpenn1980]

Yep, did mine 6mo ago....only like 14yrs after I did the PHH haha