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Post Info TOPIC: Cadillac Northstar Engine Water Pump + Housing / Crossover leaking coolant.


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Cadillac Northstar Engine Water Pump + Housing / Crossover leaking coolant.


I don't know what it is, but more and more I am seeing these Cadillac Northstar engines coming in with leaking water pump crossover housings. There are 4 gaskets between this housing that are often times overlooked when doing just a water pump. With the age of the Northstar engines getting up there these gaskets often times leak and many people have a hard timing finding the leak. What usually happens is they leak when the engine cools off, often times leaking down the side of the block.

Like anything else with the Northstar engine the intake must come off, and it's not too awful bad getting the housing out once you get the harness moved over. It's about a 7 hour job per the "book" and you can count on having some fun along the way.

At this stage I am well into the job with the intake cover and air box removed. I also have the throttle body removed at this point inspecting where all the coolant leaks are coming from. While it's quite clear the pump itself is leaking, what many fail to realize is the crossover housings on these Northstar engines have gaskets very prone to leakage. On this engine the lower block to crossover gasket was leaking coolant onto the transmission, from there it would just run all over making the leak very hard to find. Often times these crossover seals like to leak when sitting, and when they get bad like these they leak all the time, causing people to refill the coolant often. If your Northstar engine is getting to the 100K mark, then you should have these seals done at the same time as your water pump, otherwise you will still be adding coolant every so often wondering where its going. If you are using Dex Cool then you know thats expensive in of itself.

In this photo you can see the water pump crossover housing with the water pump and t-stat installed.

Here, just under the intake manifold throttle body hole you can see the massive alumimum crossover housing that holds the pump, t-stat, belt tensioner, and EGR valve. They say Chevy runs deep, but clearly this Cadillac crossover housing runs the deeper! LOL! 

 

Here you can see the termostat/water pump crossover housing cover removed. Exposed is the water pump that requires a special tool to remove and install.

Here the intake manifold is removed to make way for the massive crossover housing to clear. It is important to cover the intake manifold runners to prevent anything from falling into the engine. I have these rags removed in other photos for the purpose of showing what it actually looks like, but be sure you keep them covered. If you know your engine is leaking from the crossover gaskets to the block then you can just yank the intake with the throttle body attached and save a little time. 

Here is the engine with the crossover housing removed. It's somewhat tricky to get the bolts out with the main harness running next to the housing, but with a little work you can move the harness and access the bolts. 

Here is the left side of the block that the housing and gaskets mount to. 

 

And here is the right side.

This is the backside of the water pump crossover housing that mates to the block 

This is the front side (with water pump still installed) of the water pump crossover. 

Here are the 4 gaskets that leak coolant, slowly. I have heard stories about Northstar engines consuming coolant, my guess is it's really these seals and they are so deep in the engine not many can even see the leak.

This is a close-up of how the seals split and allow coolant to leak. Victor Reinz sells a kit containing 11 gaskets part number GS33437 otherwise you can buy them from Fel-Pro for $8.97 each (You need 4).

So there you are... When you have a Cadillac that has the Northstar engine with a customer complaint of a slow coolant leak it's a good chance the crossover gaskets are leaking.



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FAR BEYOND DRIVEN

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Nice write up!

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"If you can convince the lowest white man he's better than the best colored man, he won't notice you're picking his pocket. Hell, give him somebody to look down on, and he'll empty his pockets for you."     Lyndon B. Johnson



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Yo SELLC,

Yeah, great thread ! At least this job ( like most cars ) might provide you with bread & butter for a while, since they're all going to be bound to leak sooner or later. I'm surprised that the leak doesn't hold-off for longer since those gaskets look like they're pretty heavy-duty, & not meant to ever leak.

Rastus

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It doesn't end there... LOL! But I wished it did.

Anyway, I have always had a soft spot for these Northstar engines and the SLS and STS Cadillacs... That being the case I figured I would do a little write up about a popular engine. Of course there are many other jobs I don't even bother taking photos of, but this one just seemed to be a juicy job for a write up.

Picking up where we left off,

Here you can see the old water pump installed into the housing.

Here is a shot of my "Special tool" for the removal/install of Cadillac pumps. If you have done gas tank sending units it should be pretty much a snap.  

Here is a look at the old pump being removed after the spanner ring has been let free.

Take a look at how small that o-ring is sealing the water pump! Anyway, you have to clean this area real good and be sure to coat your new o-ring with vasaline to ensure it does not tear when installing the new pump.

This is all that's to the Northstar water pump. Not much but what a PITA!

Getting ready to clean the mating surfaces with my trusty ROLOC pads!

Here is the surface area after cleaning

And on the crossover itself.

Here is a shot of the new gasket kit, clearly you can see how swolen the old ones were.

I'll have some more photos afterwhile.



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And that's a wrap!

 



-- Edited by SELLC on Thursday 21st of November 2013 03:50:45 AM

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Hey SELLC,

Great thread & good work ! I must admit to being surprised to see such a l o n g top radiator hose LOL ! ( You'd have nearly thought it easy to redesign the radiator tanks so that shorter hoses could be used. I guess that radiator would be fitted in a few other different vehicles ). Were these engines ever put in vehicles with a rear-wheel drive set up ? A pretty nice looking bit-of-kit that engine, as I can't say that I've ever seen them in anything down in Oz !

Rastus

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Thanks Rastus! It was somewhat of a ball buster job.

The Northstar is in pretty much all of the full size Cadillac. It's a very powerfull engine and if kept up proper, smooth as silk. This paticular engine was an early model, so it did not have the coil over ignition like the newer ones.

I have never seen the Northstar engine fitted in a RWD vehicle to date. That does not mean it hasn't been done by GM or a private party. I know the Northstar replaced the 4.9 liter in most of Cadillacs full size sedans in the mid 1990's.

 



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Here's my dilemma, I have a low mileage 93 Allante. The 93-94 only waterpump belt tensioner have not been available for over a decade, despite the gmparts.com site listing it, selling it, and canceling the order hours later. Occasionally a used one might pop up on eBag for $200, and boneyards have had these cannibalize into Oblivion years ago.

So my question is does anyone know for sure if it would work for he to swap in a 95-99 crossover that would accept a 95-99 tensioner, which are available.

Or if you have a 93-94 tensioner collecting dust?


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Have you tried the aftermarket for a new tensioner?

I'm not sure if the crossovers can be interchanged, but it seems like a lot of work for just a tensioner. Unless the crossover is already leaking.



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I'm rather car-ignorant, so I'm falling on the mercy of the forum for my first post. Be gentle!

I bought a 2004 Cadillac Deville from a private seller in February 2015 and it's had a slow leak of one kind or another since I drove it home.

Since then I've replaced the water pump, the oil level sensor, and the power steering line. I've also had it to two separate shops a total of five times specifically to find the remaining leak that no one seems able to track down.

Lately I've been sliding a sheet of white plastic under the car to catch the drips overnight in hope of identifying the fluid. Typically it's just a few drops, perhaps a tablespoon, and it's bright orange, suggesting that it's coolant (Dex-Cool). My mechanic ran a pressure test on Friday and found that the radiator cap wasn't holding pressure. He replaced that, but the leak has continued.  

Today, in the parking lot at my office, I found a puddle of clear fluid, perhaps six ounces. My commute is around 35 miles, and the car's been parked about 7 hours at this point. The weather is mild: overcast, somewhat humid and about 74­°. No rain so far.

When I sopped up some of the fluid with a white paper towel, it had no color or odor, and it didn't feel greasy at all. Lying on the ground beside the car, I can see it dripping from two different places: the first is slightly forward of dead center of the car right along the driveshaft, while the other is just forward of the front axle. I suspect that the leak is originating somewhere else and dribbling along the underside to a low point before dripping to the ground.   Incidentally, I checked the level in the coolant reservoir, and it's fine.

What the heck is going on here? What's leaking? Where is it coming from? How has it escaped discovery despite five separate trips to the mechanic?

When I take it back for service again, what should I tell them to check?



-- Edited by Orrex on Monday 4th of July 2016 01:44:43 PM

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Clear liquid, aka "water" is a normal condensation discharge when using the air conditioning.



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Thanks, but I don't believe that I ran the AC yesterday.

Also, would it still be discharging 7 hours after parking the vehicle?

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All I can tell you is there is no system that runs straight H20 in your Cadillac. So where is it coming from? I don't know. You could have a partially plugged condensation drain tube, or the clear fluid could be brake fluid, or it could be antifreeze. Only you would know.



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I'm liking this condensation idea more and more.

Over the past weekend I found a few drips of DexCool, but the reservoir is full and that drip seems to have stopped.

The clear leakage also hasn't recurred since I posted, so maybe it was condensation after all.


Thanks for your input!

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One last follow up: although I didn't recall using my AC, it was pointed out to me that the windshield defogger amounts to the same thing in terms of moisture accumulation, and I definitely did run the defogger on the way to work that day, and that would certainly explain the condensation discharge.

Mystery solved, I'd say. Looks like I was simply gun-shy due to a long and frustrating history of mysterious automotive leaks.


Thanks again!

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First off, very nice and very detailed post. Second, I have a sneaking suspicion that I may need to do the same job. Here's a picture of what I found today as my coolant was once again low. I've checked all the hoses for leaks, to no avail, yet it's still leaking. Take a look and let me know what you think. Thanks



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Sure looks suspect to me! I'd fill it up and get a little pressure on the system to make sure, but it's obviously leaking.. How quickly I couldn't say.

It's not exactly a fun job, but if you take your time it's not all that bad.



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Likely just the gaskets? Or would the crossover need replacement too?



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Depends if it's pitted.. If not you should be able to re-use the crossover itself.



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In the game late,  took out xrossover(2001 cadillac Deville ) but having hard time keeping the four gaskets on while i reimstall. Any advice? Plus broke a wire not sure where the black and white wire goes? I've attached a pic, wites pulled right out from clip.



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Lorenzo Rosa


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I really don't see a black and white wire in that photo, more like a red and black and they look aftermarket. It's also hard to see where it's going.

Anyway, it's a very delicate procedure getting the later 2000-up crossovers on since the throttle body housing is part of the crossover on the later northstar engine. That being said, I like to use a little aircraft gasket sealant, let it tack up good and stick them to the crossover manifold. It also helps if you put the lowers in with the bolts installed as clearance with the transmission is somewhat tricky and they have to be in there anyway or they won't fit once the crossover is in. You have to start the bolts (a turn or two) on all four making sure they are properly seated and haven't moved. From there you start your uppers and once all are started and the seals in the proper position you can tighten it down. It takes some time and it can be quite frustrating but it's do-able. 



-- Edited by SELLC on Thursday 15th of March 2018 07:45:13 PM

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Thanks for the response, where do i get the aircraft sealant?
The red wire is really the white wire, I soldered an extension but only had a red wire. I've taken another pick hopefully it helps.



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Lorenzo Rosa


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Its called permatex hi-tack. Part # 80062

There are other brands too.

Using the stuff takes a bit of practice, so try it out first so you know when it tacks up enough to hold a gasket.

Even with this stuff helping to hold gaskets it will take great care not to knock them off while installing crossover.. Good luck.

 

 



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Morning, thanks again for the infomation.
I was wondering if you had a chance.
to look at the new pictures of the wires i attached? Sorry for keep asking.
Thanks again.

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Lorenzo Rosa


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Just looked at my last post yesterday for some reason the pictures didn't attach I'll repost with attachments.

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Lorenzo Rosa


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The red wire is really the white wire, I soldered an extension but only had a red wire. I've taken another pick hopefully it helps.15212145875401912096134.jpg



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