Don't get stranded...change out those t-connectors now

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Just food for thought:

I replace all the cars I service with the OEM plastic T’s. I believe they are meant to be plastic so that they provide a failure point before a more crucial part is damaged in the case of overheating. I would rather a T go before my radiator or worse, head gasket.

But they are definitely an item that needs to be replaced at 90k servicing IMO if you stay with the OEM T’s.
 
Question, the top 2 are larger than the bottom. Looks like 3/4" on top and 5/8" the bottom?

The brass ones posted above are 5/8" all over. Have any of you that used the brass had any issues with the size? Did you replace any of the hoses or clamps?
 
No, just takes a little more elbow to get the smaller hose on, I left my hose out in the sun as it's more flexible with heat, you can put some coolant on the inside of the hose as well to give it some lube before fitting on to T.
 
jdlobb said:
Question, the top 2 are larger than the bottom. Looks like 3/4" on top and 5/8" the bottom?

The brass ones posted above are 5/8" all over. Have any of you that used the brass had any issues with the size? Did you replace any of the hoses or clamps?
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They are actually metric. But when I did mine...I ordered Tee's that were 3/4" x 5/8" mainly because my old hoses were still in pretty good condition...but the ends were somewhat 'belled' from having been on the original plastic Tee's. IF replacing your hoses with new...you could probably get away with just 5/8" Tee's.

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I ordered those metal recommended for 100 series (in another thread, many on the Amazon page indicated they used for 100 series) and used the original clamps.

They leak. Replaced the bottom with a couple work drive clamps and they don't leak, but the other (top) do. Worm drive clamps will do the trick.

Mine were most likely original (still had all clamps pointing downwards and no signs of varying pressure on the hoses) at 192k miles.

I've read that if they're gray they are bad. DO NOT read this as "black is ok" as ours were not gray.

The job was more than a 10 min job as the clamps were oriented down and everything crumbled (I believe they were actually cracked and leaking) - meaning I had to spend some time picking out the pieces.

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On a 2000 LX 470 with 147k miles (VA/DC/PA car), the Ts were original, and seemed fine. I replaced them anyway of course. Kept them as emergency spares (I tapped them with a pair of pliers once they were out and saw no cracking or anything).
 
I'd still consider taking DirtDawg's advice on using plastic T's. Likely they will last another 100k, longer than many will own their used LC's and it's a cheap failure point considering the alternatives.
 
mripper said:
I'd still consider taking DirtDawg's advice on using plastic T's. Likely they will last another 100k, longer than many will own their used LC's and it's a cheap failure point considering the alternatives.
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Hoses will fail before a radiator will. Also, radiator caps will only hold pressure to a certain level until it opens up - you don't want the T's failing during normal operating pressures. It's kind of an odd thought that it's engineered to fail first.

Toyota has used plastic pieces in the cooling system for decades - especially when you look at the mechanical heater valves used in just about everything in the 80's and 90's. They weren't a "failure" point. I was poking through boxes looking for worm drive clamps last night and came across a plastic heater valve from a 1986 MR2 that was in flawless condition, had 200k miles and was from the rust belt.
 
toyotaspeed90 said:
Hoses will fail before a radiator will. Also, radiator caps will only hold pressure to a certain level until it opens up - you don't want the T's failing during normal operating pressures. It's kind of an odd thought that it's engineered to fail first.

Toyota has used plastic pieces in the cooling system for decades - especially when you look at the mechanical heater valves used in just about everything in the 80's and 90's. They weren't a "failure" point. I was poking through boxes looking for worm drive clamps last night and came across a plastic heater valve from a 1986 MR2 that was in flawless condition, had 200k miles and was from the rust belt.
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That’s why I stated in the event of overheating, not normal operating conditions. I’ve recently seen a 2UZ that was overheated and driven without coolant for almost 30 minutes. No hoses failed. Rad cap and rad held, with only a small crack in the rad. And the result was a blown head gasket and ruined engine. I should throw in his case of overheating was due to low coolant, but the concept is the same doesn’t matter how it overheats.

But believe what you want. I’d rather have a plastic $2 T go than anything else. And I’d rather have a few cheap points of failure than an expensive item. But then again I’d shut her off in the case of any abnormal temp.
 
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toyotaspeed90 said:
Hoses will fail before a radiator will. Also, radiator caps will only hold pressure to a certain level until it opens up - you don't want the T's failing during normal operating pressures. It's kind of an odd thought that it's engineered to fail first.

Toyota has used plastic pieces in the cooling system for decades - especially when you look at the mechanical heater valves used in just about everything in the 80's and 90's. They weren't a "failure" point. I was poking through boxes looking for worm drive clamps last night and came across a plastic heater valve from a 1986 MR2 that was in flawless condition, had 200k miles and was from the rust belt.
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I've had multiple radiator failures long before hoses fail, albeit not on a Land Cruiser. Anyway, plastic will last for years, and won't rust, so why metal? Toyota used plastic for a reason.
 
DirtDawg said:
That’s why I stated in the event of overheating, not normal operating conditions. I’ve recently seen a 2UZ that was overheated and driven without coolant for almost 30 minutes. No hoses failed. Rad cap and rad held, with only a small crack in the rad. And the result was a blown head gasket and ruined engine.

But believe what you want. I’d rather have a plastic $2 T go than anything else. And I’d rather have a few cheap points of failure than an expensive item. But then again I’d shut her off in the case of any abnormal temp.
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I'm going to guess those radiators that failed have plastic caps - got old/brittle, and failed. If you have a new $2 plastic T, it won't fail prior to an old plastic end cap on the radiator.

Also, on your example with the 30 min overheat run (which most of us who are mechanically inclined would catch early) what kind of T's were there? Why did the radiator crack and not the T's fail? Photos?


My point is that the T's will only fail if they're old/cracked and ready to fail. Them being plastic doesn't make them weaker by default - I can cut a rubber hose with a razor blade far easier than a new plastic T - the means of pressure against them are the same. The T will only fail/blow if it's already old and failing.


You guys are looking at this backwards - as if to say "if I get a crack in the radiator, the plastic T will fail and I'd rather have it fail" - but that isn't how it works. How many times in this thread have people said "my failing T saved me!" - just the inverse - it's a "PSA" stating to replace your T before it fails.

They are a weak point in the system. If something else in the system is going to fail, the plastic T isn't going to save it from failing, nor is it going to save the driver who doesn't pay attention to their gauges from blowing a head gasket.
 
If I took your principle of "because Toyota designed it this way" then I guess nobody in the 100 series forum should replace the weak frontend with an aftermarket locking diff, because Toyota must have designed it that way as a failure point to save the transmission, right?
 
I heeded the advice from many on this forum and took my 03 LX in to have the Ts checked, and its a good thing I did. As soon as my mechanic touched them they just crumbled. Fortunate to catch this in time. Thanks for all the advice guys!
 
toyotaspeed90 said:
I'm going to guess those radiators that failed have plastic caps - got old/brittle, and failed. If you have a new $2 plastic T, it won't fail prior to an old plastic end cap on the radiator.

Also, on your example with the 30 min overheat run (which most of us who are mechanically inclined would catch early) what kind of T's were there? Why did the radiator crack and not the T's fail? Photos?


My point is that the T's will only fail if they're old/cracked and ready to fail. Them being plastic doesn't make them weaker by default - I can cut a rubber hose with a razor blade far easier than a new plastic T - the means of pressure against them are the same. The T will only fail/blow if it's already old and failing.


You guys are looking at this backwards - as if to say "if I get a crack in the radiator, the plastic T will fail and I'd rather have it fail" - but that isn't how it works. How many times in this thread have people said "my failing T saved me!" - just the inverse - it's a "PSA" stating to replace your T before it fails.

They are a weak point in the system. If something else in the system is going to fail, the plastic T isn't going to save it from failing, nor is it going to save the driver who doesn't pay attention to their gauges from blowing a head gasket.
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toyotaspeed90 said:
If I took your principle of "because Toyota designed it this way" then I guess nobody in the 100 series forum should replace the weak frontend with an aftermarket locking diff, because Toyota must have designed it that way as a failure point to save the transmission, right?
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Plastic in heating systems has been proven to show rapid deterioration when intense heat is introduced. The plastic on the radiator caps is almost two times thicker than the plastic in the Ts.

The 2UZ in mention was in a friends sequoia and by the time he started overheating the coolant was down below the level of the T’s and the interior heater core. The radiator was already cracked due to the nature of our aging radiators and in turn was how he was running low on coolant. But there was still coolant running through the primary system. Once again, once he started overheating the first thing to go was the head gasket. Would the Ts have saved him in this situation? No. But that wasn’t the point I was trying to make. If you’d really like photo evidence of something I can reach out to my friend and see if he has any, though not sure what that would prove. He’s now in a 100 series though, so I’m happy.

My point is that if I’m servicing a 2UZ with an owner that I know is not mechanically-inclined, it’s getting plastic T’s. Not because I expect them to fail first in the case of overheating, but because I know they could potentially be a failure point as a metal T is not. That way if I have one of them come back and say “my truck started to overheat, and eventually started spilling coolant”, then I know there are more cheap failure points than potential expensive ones.

The case of the T actually being the cause of overheating is due to improper maintenance to replace the aged item. Completely different issue.

I never stated the claims your making. Nor did I ever praise the Toyota engineers for their design. There’s a lot of places their design lacked.

At the end of the day put what YOU want on YOUR car. I’m sticking with the OEM part.
 
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The argument doesn't make sense to me. The T's didn't save the HG from going in your example, yet you purposely put an inferior part into the vehicle that is known as a part that will fail when one that will not fail is available.

It would stand to reason to put metal T's into someones vehicle who is less inclined to pull over when they overheat and/or properly maintain the vehicle themselves.
 
toyotaspeed90 said:
The argument doesn't make sense to me. The T's didn't save the HG from going in your example, yet you purposely put an inferior part into the vehicle that is known as a part that will fail when one that will not fail is available.

It would stand to reason to put metal T's into someones vehicle who is less inclined to pull over when they overheat and/or properly maintain the vehicle themselves.
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I clearly explained it to you in the simplest way I know how. I never claimed it would have saved his head gasket. I only claimed that plastic is more likely to fail in the event of overheating compared to metal.

Also the stock T’s do way better than your giving them credit for. And when replaced at 90k/7 year intervals they are more than safe and adequate.

So I’ll end this conversation with my above statement. At the end of the day put what YOU want on YOUR car. Have a nice day.
 
Replaced my t-connectors today with OEM Toyota. I figure they should just be done every time the timing belt is. Had the belt done last week - it had never been done, 183k on the clock :censor: The tensioner was not tensioning anything and the belt was on its last legs.

Holy crap those hose clamps were in the worst possible position... the ends of the driver's side came off but both were otherwise intact. Unfortunately, I think the very end ring of the driver's side fell into the cooling line, a few grams of plastic won't hurt anything, right?
 
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I should backtrack - the plastic Ts are fine so long as:
1) you plan for their failure and replace prior. This is additional preventative maintenance, but fine so long as you continue to replace them
2) you keep the test of your coolant system perfectly in tact
3) you understand that the plastic Ts are not a purposeful fail point and shouldn't be expected to fail and save anything else from failing
 
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