Pesky heater hose /PHH (2 Viewers)
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Very recently I removed and disassemble the engine out of my 1996 with 238k miles. The PHH was a ticking time bomb.
Lot of opinions out there on the PHH.
In my case I wasn't a fan of how short that hose is with the factory hard line and how much of a hassle it would be to deal with if it ever failed when I was out and about so I went with the bypass. Now the hose makes a nice gradual turn and if something comes up (unlikely) it's much easier to swap out.
There's another small coolant hose right next to it for the throttle body. Might as well swap it out at the same time. This photo shows the PHH removed but the throttle body hose still attached.
In my case I wasn't a fan of how short that hose is with the factory hard line and how much of a hassle it would be to deal with if it ever failed when I was out and about so I went with the bypass. Now the hose makes a nice gradual turn and if something comes up (unlikely) it's much easier to swap out.
There's another small coolant hose right next to it for the throttle body. Might as well swap it out at the same time. This photo shows the PHH removed but the throttle body hose still attached.
Mark W
Yep, it's true. I just don't care that much.
I have only seen a few of them actually fail. Maybe 4. Have seen a few that were looking pretty sad and got changed out before they failed. I have worked on dozens and dozens of '80s over the years (three today) and most these days are well over 200K, many are over 300K and at least one is in the 500+K range (That one DID have a hose fail).
The smaller hose to the intake is argueably as problematic. I have had to replace two of those recently. It is a bit easier to change at least.
It is not so much that either of these are highly likely to fail. Just that they are a bit of a pita to replace if they do.
Mark...
The smaller hose to the intake is argueably as problematic. I have had to replace two of those recently. It is a bit easier to change at least.
It is not so much that either of these are highly likely to fail. Just that they are a bit of a pita to replace if they do.
Mark...
I changed mine when I did the HG @ 480000 kms and it was in really good shape though with no evidence of bulging and the inside was spotless (credit to Toyota LLC)
the only thing i did different when putting the new one on was I used Toyota constant pressure clamps on both sides as opposed to the factory install where they used one and a sardine can type clamp on the the pipe side - that was 7 years back and all good
the only thing i did different when putting the new one on was I used Toyota constant pressure clamps on both sides as opposed to the factory install where they used one and a sardine can type clamp on the the pipe side - that was 7 years back and all good
I agree that it's pesky, but I think the difficulty is overblown by some.
If you still see factory cotter pin clamps on the hose, it's original and should be replaced.
If you have easy access and it doesn't look recent, might as well replace it while you're in there.
No need to use Toyota OEM, as there are a variety of good hose options. Just use constant tension clamps.
Personally, I opted to keep the pipe, rather than a length of hose running up top, but depends on the condition of the pipe & your preference.
Agreed that the #1 bypass hose just forward of the PHH is another one to look at, if you think it may be original. I did mine when I had the throttlebody off for valve cover gasket, and it was easy. Most of the other hoses are easy-access, so you can do them later, but at this point you may as well just replace them if they're old. Pretty affordable peace of mind.
Looks can be deceiving. Both of mine looked fine, but were a bit gross once I had them off and took a closer look.
If you still see factory cotter pin clamps on the hose, it's original and should be replaced.
If you have easy access and it doesn't look recent, might as well replace it while you're in there.
No need to use Toyota OEM, as there are a variety of good hose options. Just use constant tension clamps.
Personally, I opted to keep the pipe, rather than a length of hose running up top, but depends on the condition of the pipe & your preference.
Agreed that the #1 bypass hose just forward of the PHH is another one to look at, if you think it may be original. I did mine when I had the throttlebody off for valve cover gasket, and it was easy. Most of the other hoses are easy-access, so you can do them later, but at this point you may as well just replace them if they're old. Pretty affordable peace of mind.
Looks can be deceiving. Both of mine looked fine, but were a bit gross once I had them off and took a closer look.
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banieldowen
SILVER Star
on one of my 80s I swapped it at 247k. I had been monitoring it…putting it off, then one day it started leaking coolant…
ppc
M Go Blue
Not necessarily original as the OEM replacement part also has the cotter pin clamp. That said, failures have been reported in the past starting around 100K miles. That was 20 years or more ago. Those that claim that they have high mileage vehicles with the original PHH in good condition either have not examined it thoroughly or removed it to inspect internally/completely and most likely are not the original owner so they won't know for certain that it was never replaced. Now that the vehicles are 27 to 31 years old you have a ticking time bomb.
Mark W
Yep, it's true. I just don't care that much.
In the '80 series, I have seen more radiators fail than I have PHHs. I have seen more fuel pumps fail. I have seen more head gaskets fail. I have seen more alternators fail. I have seen more oil pump seals fail. I have seen more fan clutches fail. I have seen more wheel and knuckle bearings fail. More brake calipers. More heater blowers. More pinion bearings. More birfields. More Ujoints. More AC compressors. More window motors. More PS hoses. More SRS ECMs. More O2 sensors. More TREs... More crank/rod bearing failure for that matter.
Probably other stuff I am forgetting about right now.
My point? IMHO, concerns about the PHH are overblown. They are way down on the lists of things that are going to fail or wear out. They are not really the worst job to deal with. Certainly not the most complicated or time consuming. Nowhere near the most expensive. If you are at all attuned to your vehicle they usually give warning before they let go completely.
They're a thing. But that's all. Just a thing.
Mark...
Probably other stuff I am forgetting about right now.
My point? IMHO, concerns about the PHH are overblown. They are way down on the lists of things that are going to fail or wear out. They are not really the worst job to deal with. Certainly not the most complicated or time consuming. Nowhere near the most expensive. If you are at all attuned to your vehicle they usually give warning before they let go completely.
They're a thing. But that's all. Just a thing.
Mark...
If I had a new to me 80 with uncertainty of the service record related to PHH (and likely other things), I’d be making plans for replacement/alternatives and consider it a next level baselining. It may not be an urgency or likely to fail anytime soon, but be making plans. I take some cross country off-roading trips and am generally risk aversed. I like to minimize points of failure. Everybody’s different. That said, the capacity for trail fixes that many on this forum have is astounding to me. 2 very different ways to have peace of mind.
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"More pinion bearings. More birfields. More Ujoints. More AC compressors. More window motors. More PS hoses. More SRS ECMs. More O2 sensors. More TREs."
PHH failure can lead to head warpage. Not so much a problem with the other parts.
"Nowhere near the most expensive. If you are at all attuned to your vehicle they usually give warning before they let go completely."
Heads are fairly expensive and PHH can let go with no warning.
PHH failure can lead to head warpage. Not so much a problem with the other parts.
"Nowhere near the most expensive. If you are at all attuned to your vehicle they usually give warning before they let go completely."
Heads are fairly expensive and PHH can let go with no warning.
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It could have been replaced in the time this thread has been going on…. 
Mark W
Yep, it's true. I just don't care that much.
JohnnyFish
GOLD Star
This is the PHH from the 1FZ I swapped into my '96. It's obviously not OEM. It ripped apart from the strain of turning the screw on the hose clamp.
^^^ is a good example why anyone reading this should never use generic cheapo heater hose for this repair. 5/8" GATES Green Stripe is a thicker hose than even a new OEM hose for that application.
FWIW:
For a near permanent PHH repair (?30+ years) I used a section of 5/8" GATES Green Stripe hose, then clamped it in place using two GATES Power Grip hose clamps (heat shrinkable bands) which in this short hose section do double duty and act like an extra heavy duty protective layer (they're 3/4" wide each so almost completely cover the PHH). Over that I put a section of heat sleeve insulation (due to how close it is to the EGR pipe). That might have been overkill as the head will have to come off long before that repair fails.
For another 80, close to 20 years ago, I used a section of GATES Green Stripe hose with BREEZE constant torque clamps; that repair is still good.
FWIW:
For a near permanent PHH repair (?30+ years) I used a section of 5/8" GATES Green Stripe hose, then clamped it in place using two GATES Power Grip hose clamps (heat shrinkable bands) which in this short hose section do double duty and act like an extra heavy duty protective layer (they're 3/4" wide each so almost completely cover the PHH). Over that I put a section of heat sleeve insulation (due to how close it is to the EGR pipe). That might have been overkill as the head will have to come off long before that repair fails.
For another 80, close to 20 years ago, I used a section of GATES Green Stripe hose with BREEZE constant torque clamps; that repair is still good.
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