05 STS leaky water outlet housing

[kevm14]

This one took a while to find.

First I had a bad radiator cap.

Then it was still leaking. Seemed like the thermostat housing gasket or a hose or something in that area. So I ordered a thermostat gasket because I did not replace it when I did the thermostat a year ago and thought it was biting me in the ass.

But when I looked closer at the leaking area, I realized it was not coming from the thermostat gasket or a hose. It actually seemed to be coming from...the front of the passenger side head. *gulp*

I tried not to freak out and calmed myself by realizing I would just sell the car because I don't know if I am dedicated enough to take on that kind of job on this car. But I decided to look at the forums to see if someone else has had this issue. The good news is, I found this thread:
https://www.cadillacforums.com/forums/c ... ngine.html

Ah, that actually seems like it would be my issue. And bonus, someone said the head gaskets on these do not leak to the outside. Next step was to look at the FSM so I could actually get some instructions and diagrams for whatever the hell this is. It is called the water outlet housing. And it is that thing that goes between the throttle body and intake plenum duct. It has coolant in it and connects to the front of each head with a gasket. See PDFs.

The forum said the job was actually pretty easy and the FSM agrees.

First, remove the throttle body after disconnecting the air intake and breather hose. 4 bolts and I flopped it over to the side.

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Next I disconnected one of the upper radiator hoses and let that drain. Then I disconnected the evap purge solenoid plug and line. I loosened the duct plenum hose clamp. Disconnect MAP sensor plug (the MAP sensor sits in the water outlet housing...did not know that).

Remove the 4 bolts holding the water outlet housing onto the heads. The lower right bolt is longer than the others (the manual says left, since left refers to absolute left, which is left when looking forward....a little confusing).

Then I just gently pulled until it came away from the plenum duct and heads. Not too bad actually. You can see the gaskets here. Orange. That left one is definitely what was leaking.

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Fortunately Herb Chambers had the gaskets, for a whopping $40/ea. Damn. I would have replaced the plenum duct at this point but they did not stock it. Looks like this is another way to replace it without having to pull the intake manifold. He said they used to stock the plenum duct since it was a common issue. I asked him about other common issues and he asked a tech. Other than leaks I guess these are pretty solid. That was pretty much the forum consensus.

Anyway I was pretty attentive to cleaning the gasket surfaces. I scraped gently, used carb cleaner and a shop rag, and I even lightly sanded. The new gasket material was black instead of the orange of the original gaskets, implying a possible redesign which is good, especially since this is apparently common (first I've heard of it in my forum time though).

I reinstalled and torqued the bolts. I reused the throttle body gasket, against FSM instructions (dealer did not stock). If I end up replacing the TB for that tip in lag, I will replace then. It think it is fine. I never touched the thermostat gasket or the hoses on the housing (which I had previously thought were leaking).

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All buttoned up. Filled coolant and idled. Did not see any leaks but time will tell for sure.

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[kevm14]

Fortunately Herb Chambers had the gaskets, for a whopping $40/ea. Damn.

RockAuto sells the AC Delco gaskets....for $18.60/ea. Nice dealer markup. Well I needed it that day....well the car could have stayed apart in the garage (and if I had known about the ball joint, I may have elected to order a bunch of stuff, including the plenum duct, and do it all at once, for cheaper).

I have this aversion to leaving stuff taken apart even though that is the theoretical benefit to A) a garage and B) having multiple cars. Yet I still try to fix stuff as if it were my only vehicle.

[kevm14]

So I fixed the water outlet gasket leak. But coolant was all over the place after my drive in. Just went out and started it. Let it warm up and build a little pressure. Looks like the hose I removed from the water outlet housing is leaking. Shocking. I had to work at it with channel locks so I'm sure I hurt it a bit, especially in the colder temps, and especially being the original hose.

The hose is surprisingly expensive. To the tune of $42 for the cheapest DAYCO and up to $60 or $70 for the AC Delco. Worse than that, there is with and without HD cooling. Without, the hose is 16-13/16" long. With, the hose is 15 19/32". So a difference of 1.2". Measuring a curved hose probably means no chance in getting that right. And no RPO codes listed on RockAuto.

So even though I have V03 cooling which on the STS means mechanical fan and dual electrics (which would be "heavy duty" by many standards) I believe the distinction is V08 cooling and V92 tow pack which I do NOT have. I will probably get the regular one.

Local Napa, Advance and Autozone do not stock it. Autozone sells the Dayco and like on Rockauto it is listed as with or without tow pack. I definitely do not have V92 so that's probably good enough for me. For what it's worth, Autozone's price is almost TWICE Rockauto's for the exact same Dayco hose. Side note, the SRX does have the tow package.

[kevm14]

Almost ordered the Continental because it had that factory knit cover but none of the other hoses do, and the one on the car doesn't, either....so I got the AC Delco non-towing hose for $64 shipped. Did the cheap first class shipping, too. It comes when it comes.

[kevm14]

Got home fine. Level didn't drop too much. It also did build pressure. But I grabbed the hose and bent it up and pressurized coolant shot out so... I definitely hurt it when removing it last weekend.

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[kevm14]

Hose comes Monday...

[kevm14]

I looked at the radiator side of the hose while I was working on the suspension. It is like halfway down the end tank. Very hard to reach. If I had very long needle nose or snub nose pliers that could work but I don't. Also not sure if I can get my actual spring clamp tool in there, without removing...something.

[kevm14]

Well it was a struggle to deal with that hose clamp. I actually got it off alright. But for reinstallation I tried to use the cable/remote hose clamp thing. That cable just can't pull the clamp open enough so I couldn't slip it over the nipple on the radiator. I ended up switching to regular ratcheting hose clamp pliers (from the same kit) and that worked better. I did have to remove a small coolant hose for access so hopefully this doesn't just keep cascading into more hoses. It would be fairly easy to replace at least.

Also, I thought the hose matched up but it seems to be lightly rubbing on another coolant hose. I guess that is a possible indicator that if it was 1.2" shorter, it wouldn't rub....so maybe I needed the shorter one for HD cooling/towing?

New hose (and new TB)

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Hose nest. The new hose starts at the bottom of the screen, wraps to the right a little and then loops down to the left, to the radiator.

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I don't believe I have any more leaks but I thought I didn't before, too. It is building and holding pressure. Solution? Drive it!

[Adam]

it seems to be lightly rubbing on another coolant hose. I guess that is a possible indicator that if it was 1.2" shorter, it wouldn't rub....so maybe I needed the shorter one for HD cooling/towing?

Just get some corrugated plastic sleeving and cover the hoses with that. Or if there isn't enough room, the slide on mesh stuff you already have there.

[kevm14]

So where do I get OEM quality split loom?