mmcpeck

Well another week, another problem with my 3VZE.

Noticed it when I was on my way to work this morning, had a strange smell blowing in through the vents, couldn't place the smell, didn't smell like oil burning or a coolant leak, very pungent ans strange, but it seemed to go away.

Later on I went out and did some wheeling in the snow, somehow or another my 4L just started working on it's own, but that's a different issue.

Anyway after 20 minutes or so I noticed smoke/steam coming from under the hood. Pulled over and lifted the hood and a saw it coming from the back of the engine, smelled horrible, like nothing I have ever smelled before on any vehicle, not oil, not coolant...not sure what it was, so I went home.

Once I got home I kept it running and looked around to see where it was coming from and I could see it leaking from something on the back of the engine and dripping onto the crossover exahust pipe. I watched it for a few minutes and could see a quick hint of a Red color before it quickly steamed away....then I smelled the familiar sweet smell of coolant before the other smell I have never smelled came on.

The previous owner of this 4Runner, always had it serviced by the dealer so it's got the Red Toyota coolant in it, it's pretty clean as they did the water pump along with the T-belt about 10K ago.

So my two questions are:

1. Has anybody ever smelled this Red Toyota coolant steaming away, and does it smell different than regular coolant....can't really explain what it smells like but it had a slight smell of the regular coolant before this pungent other smell.

2. What could be leaking on the back of the 3VZE that would drip onto the crossover pipe? And will the plenum have to come off to fix whatever is leaking....I think I already know the answer to that, but keeping my fingers crossed, seems like that plenum has to come off for everything.

Thanks for any help.

TNRabbit

There is a small u-shaped hose on the backside up under the intake/plenum. You have to remove the intake to get to it. It's about 7" long. That's what this sounds like..

mmcpeck

Awesome.......I knew I'd have to take that damn plenum off!!

This leak looks like it is coming further down down than the plenum though, it almost looks like it's coming from the back of the block, and it's leaking right on top of the crossover pipe.

I'm amazed at how much crap Toyota decided to cram underneath this intake plenum.

TNRabbit

There's a crossover pipe there as well. I'm guessing the leak is most likely from the hose than the pipe, but both are possible. Which side; driver or passenger? There is a coolant hose that runs through the Throttle body as well which could be leaking...

chewie1014

Welcome to building a car on an assembly line. They never factor us Shady Tree Mechanics into the process. Has anyone told you where the fuel filter on a first generation 4runner is located? Bolted to the block UNDER the intake manifold. The only way to get to it is to remove the tire, unbolt a special panel, and then feel around blindly for the bolts. It's loads of fun.

mmcpeck

TN....by crossover pipe I meant the exhuast crossover from the pass side of the engine, sorry should have specified that. Right where it goes behind the engine is where I see coolant dripping onto it. I can watch it for a few minutes and I will see a spirt of coolant about every 10 seconds. It's not really on one side or the other of the engine, it seems like it's right in the middle, and that's where it's hitting the exhaust.

The smell is what really threw me off, I have never smelled a coolant smell like this. I get a slight whiff of the normal sweet smell of coolant, but there is an overwhelming other pungent smell once it steams up.

Anyway, I am assuming that this plenum will need to come off, just to even see what's leaking.

Bobzombie

Dont forget the coolant sensor bank behind the plennum up against the fire wall.
I would check this also. There are 4 sensors in there and you could have a leak there.
Also that sensor bank has a gasket and is bolted to the intake mani.
Coolant could be running down that right to the exh crossover pipe

TNRabbit

I meant there is a coolant crossover pipe under there as well.

Yes, you'll most likely need to take the plenum off. Don't forget to get a replacement gasket. It's a PITA but necessary. MAKE SURE you remove the vacuum hose that goes to the TVV valve under the pax side or you will break the tit off it!!!

Innervision

When I swaped my engine on my 94 3vze a month ago, I had a leak similar to yours. There is a hardline that runs under the plenum and intake manifold down between the heads to the front of the block. My hardlline had rusted through and was leaking. Its called the number 1 bypass hose. It can be seen in the FSM manuals on the first page of the cylinder block section. This will at least let you see where it is and if its your problem. The hose is dead center of the block and drips down on the crossover.

If you look through your driver side wheel well you should be able to see the bottom of this hardline and see if its dripping.

This was a full days tear down and rebulid since you have to take off the intake manifold. Hopefully you just have a leaky hose or conneciton to the plenum or throttle body.

good luck

TNRabbit

That's the one I was talking about...

joebattle1

mmcpeck, Here are a few pics from my motor swap not sure if it helps but may give you an idea of what your looking for.

mt_goat

Here's some more:





If you want a close-up click the picture and select the "full size" option.

mmcpeck

Thanks for all the replies guys. The HG recall was done on this truck about 10K ago and they put new factory heads on it also, so I would assume, even thoug I shouldn't, that they at least inspected that number 1 bypass hose under the intake.

Based on joebattle's pics, it looks like it could, hopefully, be a loose connection at the furthest hose/pipe to the right in the picture, because when I was looking at it last night, it almost looked like it was coming from right next to the cam seal on the pass side rear.

I may lay on top of the motor and see if I can see the leak a little better. I will also look through the driver wheel well and see if I can see anything leaking through there.

In any case, I will just assume this is gonna be a pain in the ass.

mmcpeck

Looking at mt goat's pics, is there anyway it could be a freeze plug leaking???

The engine has good clean Red Toyota coolant in it and the coldest it's gotten around here this winter is like 10 degrees.

TNRabbit

"In any case, I will just assume this is gonna be a pain in the ass."

I used to think that about removing the plenum until I replaced a timing belt... then did an entire rebuild after a HG failure... :-)

jht3

chiming in here because i've got the same issue, but i can't for the life of me track down where it's coming from.

i can smell burning coolant after a driving. the hoses all pass a visual test, and i can't feel anything wet when stick my hand down the firewall side of the motor; inspecting the hoses and freeze plugs. from topside, everything looks ok. looking through the wheel wells also shows me nothing. from underneath it's an entirely different story. the bellhousing is soaked with clean coolant, mostly the drivers side. it does however look like the leak originates on the passenger side but as you all know it is difficult to see clearly.

i've examined my FSM and looked at the pictures so my hope is it is a hose at the back of the engine that only leaks when the system is pressured. i'm going to start with bypass hose #3 and maybe hose #5. #3 is looking old but there are no signs of coolant leaks.

my hope is that it is NOT the #1 bypass pipe itself or the bypass outlet gasket. assuming it is, what is the minimum number of parts i'd have to remove to get down to the pipe? can the power steering, timing belt, distributor, and EGR be left on the engine?

scope103

Yikes! Leave the power steering, timing belt and distributor alone.

You will need to remove the plenum (which is a fiddly job; do take careful notes, label everything, take pictures, blah, blah,...) Since 90% of the EGR is mounted to the plenum, it is easiest to take it off first. Once the plenum is off you're still not getting perfect access, as the distribution block is below the top of the intake manifold. But you should be able to do whatever you need to do.

woodendude

In the above picture right above the exhaust crossover pipe you see a U(upside down u) black coolant pipe. That went on mine, I was able to change it out with out removing anything but I did have to scrape the hell out of my hand to do it. And a set of the long handled curved needle nose pliers helps big time!

jht3

thanks. the FSM tells you to remove nearly everything to access that area. i assume all i'll need is a new plenum gasket?

does everyone just reuse the compression clips?

scope103

Sigh ... In theory that's all you'll need. In practice, you'll break something along the way.

If by compression clips you mean the spring-type hose clamps, you should have little trouble reusing those. Most of what you're disconnecting is air or vacuum, you can make your own assessment in the places where you're disconnecting coolant lines.

You will be disconnecting one fuel line to the cold-start injector. It is a "banjo" fitting with two aluminum washers. Most commentors have gotten away with re-using them (the advantage is that it is easy to get to if you have to go back and put in new washers). I haven't found those washers anywhere but the dealer; not expensive but they'll have to order them.

You MUST be very careful with the vacuum line that runs from the charcoal cannister to the TVV (thermal vacuum valve) on the distribution block. Like most such valves, the vacuum part is plastic, and the environment in which it sits turns it into Captain Crunch. If you very carefully pull on the hose from the cannister end ... you'll break off the plastic nipple for sure.

The coolant line that connects just below the throttle plate is difficult to reach; I leave that to the end where I can unbolt the plenum and lift it about 1-2cm. I use lineman's pliers (they have a wide jaw) to squeeze the spring clips.

The part that always gives me the most difficulty is the 1" short rubber line that goes to the PAIR valve (passenger side aft). Hard to get to, nothing to push against, and too short to rotate to get it to let go. I've had some luck using a hot air gun to warm up all older rubber lines; if you get them a little softer they cooperate. Put your hand on the line as you're heating it; if it's too hot for your hand then you're overdoing it.

If all else fails and the PAIR line is all that is holding you, you might be able to lift the plenum enough to unbolt the web of metal tubing below the plenum. Lift the plenum away, and with better access you can release the PAIR line.

When you search these forums (which I know you've already done), you'll see lots of postings that start "Where does this line go ...?" Don't be one of those guys. Take the time to draw a picture, use masking tape for labels, use that digital camera -- the lines going to the Plenum are not clearly documented in the FSM.