Water Bypass Pipe No.1

Hello everyone. Im new to the forum. I have a 2005 tacoma standard cab with the 2.7 L4 2trfe, 5spd trans with 200,000 miles on it. I cant seem to find any help online or in my own repair manual about the replacing the water bypass pipe no.1 located between the engine block and the intake manifold. It runs from the thermostat housing along the block to the rear of the engine compartment by the starter. Tried to replace it without removing the intake manifold but was unsuccessfull in doing so. I also tried a new gasket and that did not fix the problem. Ive reluctantly used Barrs copper stop leak for a bit now but the leak has now come back after about 8 months. I think its cracked around the front of the pipe close to where it bolts up to the thermostat housing but cant tell because the area is so compact that I cant get a good look at it. All I can see is dried coolant where the stop leak has plugged it. Supposedly I will have to remove the fuel injectors along with the throttle body assembly just to remove the intake manifold. Is there a way around that? I have a little know how as I can do most general upkeep on my own but am afraid that this may be a little too involved for me to take on. If anyone on the forum has had to replace the water bypass pipe no.1 can you please share your experience and knowledge of the job with me. I hope this can be a job I can do myself as I already have all the parts to do the job but just a lack of knowledge. Im afraid that if I take it to a mechanic theyre gonna charge me a buttload to replace a $25 part. Thank you for any input and knowledge on my situation.

 

Hey SMS- I have an '05 with the 4-cylinder and 218K miles and just this last week had exactly the same problem. The pipe is 100% molded plastic and bolts with a 2-bolt flange to the back of the thermostat housing, runs straight back alongside the block, then turns left (toward the left side of the truck) and ends with a bolted flange and 2 water hose outlets, 1 larger one for the cabin heater core and 1 smaller one for the water feed up into the throttle body.

My pipe was leaking at both ends but you absolutely cannot see the rear connections with the inlet manifold in place and of course, the rear connection was the worse leak. When I finally got the pipe out, the outlet-barb going to the throttle body was completely broken free from the rest of the pipe and when I squeezed the rubber hose with pliers to force the outlet out of the hose, it came out in chunks. I was lucky that the front was also leaking as I was just about to pull the head for a new head gasket when I spotted the bypass pipe leak.

One of the mechanics at Toyota of Stockton (California) told me that he thought I could get the bypass pipe out and back in with the inlet manifold in place but I just can't see how that would happen. The rear of the bypass pipe is bolted to a tab near the starter mount and you'd have to have really small hands and already know what the situation looks like as you'd be doing the job blind.

It wasn't really that big a deal to pull the inlet manifold although getting the rear vent tube back in place made me swear 4 times. I unbolted the fuel return pipe but did not disturb the inlet pipe, injectors or the fuel lines. I did have to slightly bend the auto tranny dipstick a bit as it bolts to the manifold but I felt that was better than disturbing the dipstick at the tranny. The flat-rate manual does have a time listed for the bypass pipe (.9 hours) but it also adds 1.7 hours to R&R the manifold and does say that pulling the manifold is a must. I have the Clymer manual and it has no info on the bypass pipe itself but once you get the manifold off the pipe is self-explanatory.

I'm a fairly experienced hobby mechanic and the job was irritating but straightforward. There is no way this pipe would have been made of plastic or would have failed on my 22R truck. I like the power and comfort of my Tacoma and plan to keep it a good bit longer, but it is simply becoming clear that Toyota isn't building trucks like they used to.

 

THANKS FOR THE INFO WILL PULL THE INTAKE, THIS WILL SAVE ME TON'S OF TIME AND SWEARING.......................RON B

 

I have the same problem and it is evident that I will need to pull the inlet manifold. Thanks for the post

 

I have this same problem and originally thought it was the thermastat housing leaking and after taking that off learned it wasn't the case. About how long did this take for you guys to do?

 

Not too difficult, but takes time getting to the pipe due to inlet manifold. The original on my 2005 was plastic and the replacement from the dealer was metal. It fits perfectly. Good luck

 

My 05 cracked both ends of the plastic pipe. My local shop pulled the intake , replaced plastic with steel for $160. Easy fix. Now I just have to get under and clean up the mess left by coolant leaking for too long.

 

Hey guys, just got around to pulling my intake manifold to get to this bypass pipe. A lot easier then I expected. The hardest part on the removal was getting off the PVC hose off the back of the manifold that I forgot and was hung up on. I ended up just cutting it and will replace it. I was able to pull the intake without removing the fuel rail or injectors. I couldn't really tell where exactly it was leaking so I have paper towels lined up under a couple spots to let it sit over night and see where and if there are any other spots leaking. We'll see. Thanks for all your guys earlier input.

 

Does anyone know the easiest way to remove the manifold ? Seems there is a lot of fuel lines and such that may or may not need to be removed? Any steps would be great

 

I have the same issue and don't see any evidence of it leaking at the starter area. Can the new metal flange be installed and just cut the end of the hose and spice it to avoid removing everything? Just a thought.

 

Same issue here. Noticed coolant leaking onto driveway. Saw crusted coolant on the rear of the thermo housing and when I went on a mission to find where the molded plastic coolant line went, I reached down my firewall, found a connection where the throttle body coolant line attached via a hard plastic fitting. I barely wiggled the throttle body coolant line and it snapped off! The little plastic barb where it attached was brittle. To say I was pissed is an understatement but finally calmed down and realized if it was that brittle, it was just a matter of time before it snapped off when I was driving down the highway. Anyway, I'm half way thru the repair. You HAVE to pull the intake manifold. I only had to disconnect a couple fuel line (didn't have to remove the fuel rail). The intake manifold bolts are a PITA to get to (well 5 are easy on the top, the bottom two you have to find blindly). The intake mani comes out fairly easily. My coolant bypass pipe was so brittle the end at the thermo housing snapped off before I could unbolt it. Again, luckily it happened in my driveway. This was the source of the original leak so I think it was cracked already.

 

The part number I find is obsolete and no longer sold (16268-75091). I've only found a vague reference to a new part number (

$73 16268-75130 Engine Coolant Bypass Hose

16268-75130 don't quote me on the new part #...I'm going to dealership this morning to buy one...so we'll see). Hopefully it's metal and not plastic. Really Toyota? Plastic?

 

Excellent write up.


QUOTE="toddwarren2, post: 11865406, member: 178898"]Same issue here. Noticed coolant leaking onto driveway. Saw crusted coolant on the rear of the thermo housing and when I went on a mission to find where the molded plastic coolant line went, I reached down my firewall, found a connection where the throttle body coolant line attached via a hard plastic fitting. I barely wiggled the throttle body coolant line and it snapped off! The little plastic barb where it attached was brittle. To say I was pissed is an understatement but finally calmed down and realized if it was that brittle, it was just a matter of time before it snapped off when I was driving down the highway. Anyway, I'm half way thru the repair. You HAVE to pull the intake manifold. I only had to disconnect a couple fuel line (didn't have to remove the fuel rail). The intake manifold bolts are a PITA to get to (well 5 are easy on the top, the bottom two you have to find blindly). The intake mani comes out fairly easily. My coolant bypass pipe was so brittle the end at the thermo housing snapped off before I could unbolt it. Again, luckily it happened in my driveway. This was the source of the original leak so I think it was cracked already.




[/QUOTE]

 

Appreciate it if you can post your results on the exact part number on that specific part?

Maybe even a picture of it as well?

Thanks

 

16268-75110 is the bypass pipe in steel. This particular one has the bracket on the firewall end where the heater core and throttle body coolant lines attach. I think there's another version that doesn't have the bracket, but how would it keep from vibrating the hoses off at some point if it didn't have the bracket? The parts guy at Toyota said there's been a lot of these leaks and failures of the molded plastic bypass pipe. Ya think?! The gasket is 16258-75021. It's a flat gasket. I also replaced my thermostat, upper and lower radiator hoses. I mean, why not since my coolant was puked all over the driveway!

The intake manifold must come off. Don't fret. It's not too bad. Lower bolts are goofy to get to but doable. Only had to disconnect a few fuel lines and some electrical connectors. Make sure when you're reinstalling the intake mani that you reconnect the breather line near the firewall. Ya...I almost had to take it all back apart to get the damned thing back on there. Very small length of tubing and virtually impossible to make it bend correctly if the whole assembly is bolted in already. Luckily I was able squeak out just enuf room after I disconnected the breather tube/pcv tube (I think that's what it is) bracket. Just do yourself a fav and don't forget. Oh, and the nut that goes on to the top/back intake mani threaded post...ya, it's gunna fall directly down and disappear between the starter and the tranny. There's just enuf room for it to squeeze in the gap and get stuck somewhere almost impossible to retrieve. It took me 45 freaking minutes to figure out where it went and retrieve it. I came up with some new cuss words. But I digress. Hope this helps someone out there.

 

A couple of other shots of the front and back of the pipe- just for giggles. If you look closely at the top of the pic of the back connection (near firewall), you'll see the little bastard breather hose that I failed to hook up before I secured the intake mani.

 

Excellent!

 

I hope I am not intruding on the thread but I have some what of the opposite trouble. I have a 2.7 ltr 3rzfe engine that I am building a off road racer and I cannot remember which port on the throttle body that the water by passed hoses need to be connected to.

If someone could look at my pick and tell which hose goes to which tube on the TB that would be great.

Thanks.

Charlie

 

Wondering - would it be good preventative maintenance to have this done when they do my frame ?? Might be less $$ if they don't have to remove the manifold. What do you all think ? Any reply appreciated.

 

george3- are you getting a new frame under the recall? If so, hell ya- have them replace the coolant bypass tube at the same time. I mean, they're gunna have he whole engine out, right?