CLRH2O

It's looking like this one's going to be a doozy. But who knows I could be wrong.

From what I'm posting here (one image and two short video clips) I'd like to gather a few ideas of what you guys think has happened to my 1UZ:





[Close up of possible hole?]
http://www.theforcecollective.com/we...wn_head_02.mp4

[Steam from Overheating / Location Overview]
http://www.theforcecollective.com/we...wn_head_01.mp4



The location you're seeing is located at the front of the engine. It's tucked up in the corner at the junction of the passenger side head, the timing cam sprocket cover (the large plastic cover that encloses the spark rotor assembly and plug wire ends) and I *think" the edge of the metal Timing Belt Cover (enclosing the water pump and everything else)

But It appears that the head has a small hole in it about the size of a pea just below the bolt that holds that plastic cover to it is - right at the seam between those two parts. Watch the second video carefully and you can see depth in the yellow spot - it's like a pit sort of.

You're able to see the water drain only because I took off the thermostat and filled the block from that location. Under normal driving use, within 10 minutes nearly the entire coolant fill will have been evacuated.

So. Any thoughts on what's happened here... And most importantly what work needs to be done to fix my aging 1UZ?

CLRH2O

Anyone.. Bueller, Bueller?

CLRH2O

After looking at this a bit closer, it's definitely a hole of some sort.. but I cant tell if it's maybe the natural pattern / shape of the metal just with rust over it - or a damage spot...

Is there is ANYONE on this board with some insight based on the two videos and image I've posted?

durps

iTrader: (8)

Try posting on the ls400 page as well since they use the same 1uz.

Ali SC3

iTrader: (10)

If you are having trouble figuring it out when its in front of you its difficult for us to tell over a video.
looks like a crack.

1JZPWRD

iTrader: (59)

It is kinda hard to see exactly where it is coming from. I would tear the front half of the engine down, and inspect the water pump. There is a rubber seal behind the water pump (on the housing) that could be the problem, and make it look like there is where it is coming from. Wipe off the area clean, and post up another video of it dry then maybe we could give you a different perspective on this. The water pump problem is a shot in the dark and maybe too far away from this area. I do know the drive belt needs to be replaced. It is worn. The heads normally don't go bad, but if there has been no service done, it could be just that. If indeed it is, I would also replace the starter while you are in there and of course do all the seals, water pump, hoses, thermostat, etc.

Ali SC3

iTrader: (10)

is that the valve cover bolt in the video or for some accessory, trying to figure out what angle we are looking at it here. what color is your coolant, trying to figure out if that is oil or coolant. seems like its flowing too fast for oil.

if the head warps bad enough which can happen on an overheat it can leak out stuff sometimes, usually coolant.
the crack is unusual for the block on an n/a 1uz but for it to warp and leak is not.

I will say 1jzpwrd is right, it looks bad enough to warrant dissasembly and inspection. I am sure once you start removing things the problem will present itself, and you will be able to see if the block is cracked or not.

1JZPWRD

iTrader: (59)

It looks like the valve cover bolt to me.

Ali SC3

iTrader: (10)

On second thought it does look like a hole, and if thats the valve cover bolt above it isn't there suposssed to be a part that comes out of the block for that bolt to bolt down in to. looks like its missing.
maybe someone monster torqed the valve covers and it broke that piece off the block or something.

I think you are gonna need a new 1uz if that block has a hole.

CLRH2O

Oh man - THANK YOU for a little community love finally trickling in The SC400 board seems to be winding down this past year - I was getting worried ;D

Additional question - what are the materials of our Head, Block, and valve Covers made of?

The bolt you see there is part of the timing belt cover - and I'm guessing is attaching to the Head? It's such a horrible angle / spot to get a good look at isn't it?!

I replaced the starter at about 120k - and the engine is currently at 166k. I'm the second owner (since 2007) and the original owner was an old man from FT. Meyers in Florida who had full dealer papers on service through it's final 100k visit (I bought the car with 107k on the ODO). All in all, it's been treated fairly well and to my knowledge the head hasn't been removed before... But, the timing belt cover for the distributor cap and rotors was when I replaced those along with new plugs and wires back @ 150k...... But I'm no monster when it comes to replacing bolts on parts. If anything I'm pretty careful... but who knows?

Here's what I'm going to do - I'm going to see about cleaning out that area some and get some more photos and video - I'll start there.

In the meantime - in answer to a question - it's coolant that is leaking. In specific it's pure water that I was pouring into the engine through the thermometer location at the top front of motor when I'd had that removed for replacement (thinking my overheating might as been that). I actually finally located the leak during that little operation after the first test with the new thermometer installed. I'd pour the water in, and it would drain out just as fast as you see in the videos there. Scary stuff!

As for the tear-down and rebuild work it's self - I *think* I'm up to it as I've done simular types of things before on a Mazda MX-6 and my VQ35DE - but my amount of spare time is not having it :/ And having someone else do the work, from what I can tell of the invasiveness of this inspection, is likely in the $1500 to $2500 range.... which as Ali SC3 suggested, might just warrant getting a whole new 1UZ to drop in there instead for around $1500 out the door (engine and install).

But, for now - lets see about cleaning up that location to get a better look Pics soon.

Thank you again for chiming in on this crew!

CLRH2O

ok - here's the update so far:



From what I can tell the leak is coming out of what appears to be the lower of two Head end freeze plugs.... Do our heads even have Freeze Plugs on them?

Again though, this is still only assumption as I haven't removed the cam sprocket and timing belt rear-cover which is the actual part blocking the leak location from dead on visibility. But it's where I'm at so far - any thoughts?

[And a cleaned location video showing the 'freeze plug' area?]
http://www.theforcecollective.com/webposts/sc400_possible_blown_head_03.mp4

94SC4

Did you find the problem? If not, check your front crossover pipe. Mine leaked at 210K miles and it was difficult to find the problem. It looked a lot like yours and I first thought I had a busted head gasket. Much to my surprise, all I needed to replace was a $10 gasket.

CLRH2O

Hello all - just wanted to touch base again and let you know that this freeze plug was indeed the source of the leak. I'm onto other parts of the repair process now (which include new questions as well - such as why is there no coolant behind the upper freeze plug when there is behind the lower that was my leak spot?) - but I'll give a picture blow by blow soon... just been busy with life and such

Ali SC3

iTrader: (10)

its looking alot better, good think it was something easy right =)

CLRH2O

Question:



While replacing the freeze plugs I noticed something VERY odd - the bottom plug had rusted away on the backside to the point where there was a large hole in the bottom section of it - this was the coolant leak point. I removed that plug, saw the damage, replaced and moved on to the plug vertically above it. Upon removing that plug I noticed that it was nearly new (even 20 years later) and seemed to tarnished the exact same color and with the exact same materials as the cams and everything else in the valve chamber.... the space behind that plug in the head it's self was also devoid of coolant - while the plug directly beneath it I'd just replaced was filled with coolant.

Why is that?