Need advice with PHH (1 Viewer)

[the stig]

That is fine.

I don't agree. If the bypass was a good idea, the Toyota engineers would have done it.

Good thing we don't have to agree lol

I feel like the PHH was a poor design. Like maybe the engineers designed the heater system on Friday afternoon, and everyone just wanted to leave for the weekend, so instead of making a hardline from the block up to the top, they just said "screw it, just put a short little nub that is almost impossible to reach and lets go get wasted!" Evidence of this theory can be seen in the rear heater lines as well. Maybe they were designed poorly so people would have to bring them to the stealership do get repaired. Engineered to fail.

 

[NCFJ54]

If the toyota engineers did such a good job with the design we wouldnt be calling it "pesky" in the first place

 

[120mm]

Good thing we don't have to agree lol

I feel like the PHH was a poor design. Like maybe the engineers designed the heater system on Friday afternoon, and everyone just wanted to leave for the weekend, so instead of making a hardline from the block up to the top, they just said "screw it, just put a short little nub that is almost impossible to reach and lets go get wasted!" Evidence of this theory can be seen in the rear heater lines as well. Maybe they were designed poorly so people would have to bring them to the stealership do get repaired. Engineered to fail.

It's obvious you do not understand the engineering reasons for doing it this way.

A hard line that fastens directly to the block would suffer premature failure due to vibration and would be extremely fragile during maintenance and repair. The three cylinder engine in the Geo Metro had a hard line directly at the engine, and you could literally destroy your engine by leaning on the heater hose. They were also prone to failure due to vibration.

While it may be "pesky", the flipping thing not only does its job, the maintenance interval between replacement is long enough to justify the difficulty in replacing it.

Engineering is the art and science of choosing which evil you are willing to live with. The Series 80 reflects this, as does any vehicle. While I am not a blind follower of all things Toyota, I think caution is warranted when modifying this equipment.

 

[120mm]

That is fine.

I don't agree. If the bypass was a good idea, the Toyota engineers would have done it.

I hardly ever buy into this logic, but in this case, I go with the Toyota engineers. (and you) They chose the hard lines, obviously, to clean up the engine bay and to give maintainers room to work. This forced them to use several short runs of soft hose to insulate the hard lines from shock/vibration. They decided to trade off ease of hose replacement for access to other aspects of the engine.

 

[the stig]

It's obvious you do not understand the engineering reasons for doing it this way.

A hard line that fastens directly to the block would suffer premature failure due to vibration and would be extremely fragile during maintenance and repair. The three cylinder engine in the Geo Metro had a hard line directly at the engine, and you could literally destroy your engine by leaning on the heater hose. They were also prone to failure due to vibration.

While it may be "pesky", the flipping thing not only does its job, the maintenance interval between replacement is long enough to justify the difficulty in replacing it.

Engineering is the art and science of choosing which evil you are willing to live with. The Series 80 reflects this, as does any vehicle. While I am not a blind follower of all things Toyota, I think caution is warranted when modifying this equipment.

You sir are correct, I am obviously not an Engineer. And your reasoning is sound. I would still be interested in to pick their brains (the engineers). Can you explain why they used the s***ty, thin walled pipes for the rear heater, in a place that is prone to corrosive elements? I'm not saying they didn't have their reasoning. All I'm saying is I think there was a better way. Engineers make mistakes (I work with them on a daily basis). An engineer with no mechanical hands on experience is a scary thing.

And engineers don't design cars to be bullet proof. The technology is out there to make things last a very long time, but the cost doesn't always pay off. So instead of designing a bullet proof system, sometimes they make sacrifices. Usually they are acceptable ones. Sometimes not.

 

[AJP]

It's obvious you do not understand the engineering reasons for doing it this way.

A hard line that fastens directly to the block would suffer premature failure due to vibration and would be extremely fragile during maintenance and repair. The three cylinder engine in the Geo Metro had a hard line directly at the engine, and you could literally destroy your engine by leaning on the heater hose. They were also prone to failure due to vibration.

While it may be "pesky", the flipping thing not only does its job, the maintenance interval between replacement is long enough to justify the difficulty in replacing it.

Engineering is the art and science of choosing which evil you are willing to live with. The Series 80 reflects this, as does any vehicle. While I am not a blind follower of all things Toyota, I think caution is warranted when modifying this equipment.

so first its useful to understand that the PHH that sits at the bottom end of the Heater Inlet Pipe ... is connected to the Head .. not the Block. Presumably Toyota realized you would be doing a head gasket about the time the hose was ready to be replaced ... the original hose section lasts a long time ... unfortunately NOT the stupid pin clamps they use which start to fall apart as soon as they see winter road salt. Before I did my HG .. I had to replace my clamps on the PHH with stainless worm gear hose clamps and the hose was pretty good.

Incidentally I was not comfortable rocking the pipe back and forth to break the tab when I did the head gasket ... I was a little worried that it would leave a tear in the tube ... BUT when I removed the head ... and had sufficient access I left the bolt that holds the lower tab out! The top tab is secured and more than adequate for the purpose.

 

[120mm]

You sir are correct, I am obviously not an Engineer. And your reasoning is sound. I would still be interested in to pick their brains (the engineers). Can you explain why they used the s***ty, thin walled pipes for the rear heater, in a place that is prone to corrosive elements? I'm not saying they didn't have their reasoning. All I'm saying is I think there was a better way. Engineers make mistakes (I work with them on a daily basis). An engineer with no mechanical hands on experience is a scary thing.

And engineers don't design cars to be bullet proof. The technology is out there to make things last a very long time, but the cost doesn't always pay off. So instead of designing a bullet proof system, sometimes they make sacrifices. Usually they are acceptable ones. Sometimes not.

I'm a non-engineer as well, but do a lot of evaluation of engineering for a living. Mainly I try to dig out how culture influences those trade-offs.

You're right, though; engineers often assume risk on behalf of the poor SOB who has to open the machine up and do maintenance on it. Airbus engineers, I'm looking at you when I say that, you @#$%&*! jerks.

 

[the stig]

I'm a non-engineer as well, but do a lot of evaluation of engineering for a living. Mainly I try to dig out how culture influences those trade-offs.

You're right, though; engineers often assume risk on behalf of the poor SOB who has to open the machine up and do maintenance on it. Airbus engineers, I'm looking at you when I say that, you @#$%&*! jerks.

ahhh, aviation field. I feel your pain. I can't get my engineers to cooperate for jack. Its easier for them to ignore something than to take the risk and sign off on something. I get it though. Some of them just use it as an excuse to be lazy though. I'm an A&P for uncle sam my self. Building Jet Engines for the KC-135

 

[120mm]

ahhh, aviation field. I feel your pain. I can't get my engineers to cooperate for jack. Its easier for them to ignore something than to take the risk and sign off on something. I get it though. Some of them just use it as an excuse to be lazy though. I'm an A&P for uncle sam my self. Building Jet Engines for the KC-135

I was an A&P for several years, then someone decided my Master's in International Relations qualified me to evaluate cultural influences on technology.

It's a fun lifestyle, but I most enjoy trying to get inside the heads of engineers and other tech creators to figure out why they do what they do.

 

[the stig]

I was an A&P for several years, then someone decided my Master's in International Relations qualified me to evaluate cultural influences on technology.

It's a fun lifestyle, but I most enjoy trying to get inside the heads of engineers and other tech creators to figure out why they do what they do.

Your job sounds like fun. I would be interested in such a job. Been trying to figure out what to get my bachelors degree in. Aviation something. Maybe Ill save up and go for engineering.

 

[Irish Reiver]

Your job sounds like fun. I would be interested in such a job. Been trying to figure out what to get my bachelors degree in. Aviation something. Maybe Ill save up and go for engineering.

I went to college to study electrical engineering. My first real job after college was in telecommunications and then about 10 years back I got into the aviation sector. I wouldn't leave aviation for the world. Of the 3 nothing gets my jucies flowing like aircraft support & maintenance.

 

[the stig]

I went to college to study electrical engineering. My first real job after college was in telecommunications and then about 10 years back I got into the aviation sector. I wouldn't leave aviation for the world. Of the 3 nothing gets my jucies flowing like aircraft support & maintenance.

I've always loved aviation in general. Love flying. Love planes. getting my A&P got me in the field, now Im just trying to position myself to move up to where I wanna go. Just gotta decide where I wanna go lol

 

[Whiskey74]

So, I got the PHH changed today. When I went to fill it back up with 50/50 antifreeze, it took only about 2.75 gallons to fill back up, including overflow reservoir. Ran it for about 30 min with front heater and defroster on high. Also had rear heat on high. Never had to add anymore coolant. I was expecting a drop, but, it never happened. Thought I read on here that this motor holds 4 gallons. Should I be concerned?

 

[the stig]

So, I got the PHH changed today. When I went to fill it back up with 50/50 antifreeze, it took only about 2.75 gallons to fill back up, including overflow reservoir. Ran it for about 30 min with front heater and defroster on high. Also had rear heat on high. Never had to add anymore coolant. I was expecting a drop, but, it never happened. Thought I read on here that this motor holds 4 gallons. Should I be concerned?

The block holds something like a couple gallons. One of the write-ups in the FAQ goes over this, I believe it was E9999's write up. If you didnt open the block drain plug, you still had a some fluid left in there. Just make sure its topped off and no air bubbles. Should be good.

 

[the stig]

and congrats on getting it done. Feels good, doesn't it

 

[Whiskey74]

The block holds something like a couple gallons. One of the write-ups in the FAQ goes over this, I believe it was E9999's write up. If you didnt open the block drain plug, you still had a some fluid left in there. Just make sure its topped off and no air bubbles. Should be good.

Thanks!

 

[Whiskey74]

Actually, it's bittersweet. I have to do it again because the only replacement hose I could get last minute was a scrap piece that advance auto had. Inner diameter is slightly larger and hose wall about half as thick. Made sure to tighten clamps down really good and ordered the extreme silicone replacement from phhkits.com for a permanent fix. I just can't trust this scrap piece to not leave me stranded. Definitely won't take as long the next time though.

 

[AJP]

Actually, it's bittersweet. I have to do it again because the only replacement hose I could get last minute was a scrap piece that advance auto had. Inner diameter is slightly larger and hose wall about half as thick. Made sure to tighten clamps down really good and ordered the extreme silicone replacement from phhkits.com for a permanent fix. I just can't trust this scrap piece to not leave me stranded. Definitely won't take as long the next time though.

When I did my head gasket I also did my PHH and used silicon and the breeze constant torque hose clamps. It was easy with the head on the ground ... BUT the Breeze clamps are quite large and they have to be oriented correctly. I also used Napa hose (their premium line) for the upper heater hoses because I couldnt find Gates Green Stripe. Personally - if I were doing it again I would have no issues using Green Stripe (or the high end Napa) for the PHH .. and stay with the standard SS hose clamps .. (incidentally there is a proper torque setting recommended for silicon hose and the breeze clamps fwiw)

 

[antor]

Started my PHH today and couldn't for the life of me get the bottom bolt off. Glad I read this Ill just do the Pin_Head method and break it. So I have to cut the PHH in half before breaking the lower bracket off? Im using the silicone with the constant torque clamps what would be the torque setting ^^ for the clamps.

Thanks, Antor

 

[AJP]

Started my PHH today and couldn't for the life of me get the bottom bolt off. Glad I read this Ill just do the Pin_Head method and break it. So I have to cut the PHH in half before breaking the lower bracket off?

Thanks, Antor

yes ...cut the PHH in order to free both ends of the pipe so that you can swing the pipe back and forth to weaken and break the lower tab that is bolted behind the engine .. where it is almost impossible to reach (although some have managed it apparently) .. this is what others have done successfully.

IF you could manage to just loosen the lower bolt I believe that you will be able to swing the Heater Inlet Pipe far enough that you can insert a cut length of hose between the nipple (in the head) and the pipe then force them together into the hose and re-clamp.