Sediment buildup in water jacket???
 

I've been working on a 1998 Cadillac STS.
It has the infamous front wheel drive 4.6L 32Valve Northstar V8.

The car is in decent shape and has just over 95k miles on it. I bought it with the main issue that it overheats. Having had a Northstar in the past and knowing a lot of the issues with them, basically the headgaskets will all fail eventually, I decided to fix this one with a set of aftermarket head studs.

The repair job is a pain to put it nicely. But I wanted to do it anyway.
I dropped the front cradle and the motor and trans last week or so. Then I started some of the tear down to actually get the heads off. That's where I dealt with the y pipe issue I had talked about in the other thread in the fabrication forum.

Today I pulled both heads. The new head studs arrived Friday so I was hoping to get the block drilled tapped and studded tonight. Once I had both heads off, I noticed something odd in the water jacket of the number 2 cylinder. It looked almost like granular sand had accumulated around the cylinder(3/4 of the way around and about 1/2 way up the water jacket at the outer side). Number 4 cylinder had some but much less build up, number 6 and 8 water jackets were 100% clear down to the bottom. All the water jackets are interconnected and the flow looks like it enters the bloack by #8 cylinder. I then looked at the other side of the engine and noticed buildup as well around #1 cylinder. It wasn't as much as by #7 but still enough.

The debris has the appearance of sand(different colors and granular), but with a softer rubbery texture, not hard and grainy. My cell phone died so I couldn't get a picture of it tonight. I looked at the opening for the water pump/thermostat and i saw a trace inside that area of a few grains of whatever that stuff is.

I'm trying to figure out what the sediment is. I have two thoughts. One is that it is the left over residue of some type of leak stop product. It ran through the coolant system and built up where the flow was decreased. If that is the case, then it is though the whole coolant system, radiator, heater core etc, and makes fixing the car now financially pointless. If it was leak stop it could have clogged things up so bad that could be why the motor was overheating. They could have used the leak stop the try to battle a headgasket issue. My other thought is that it is pieces of the head gasket that broke away and built up. The gaskets looked ok though and the only issue was that the stock head bolts were all sorts of tightness. Some were a pain to break free others practically had the washers lose before i even touched them.
Either case, I think the car now needs too much additional work and I should cut my losses now. I'm just still curious as to what it could be from.

I'd guess the sediment is the leak stop product like you mentioned. It's not supposed to clog things but I could see a desperate person dropping in more than recommended.

Doesn't look like dex cool cancer?

Iirc caddy used stop leak as an official fix on those cars

Here are two pics uploaded from my tablet. I have more on my digital camera I'll upload when I get home.

That kind of looks like oodles of stop-leak to me.

So would you guys consider the car a loss? not as in not fixable, but as in not worth it.
Basically, how much money would you feel comfortable dumping into it?

I figure the radiator and heater core are full of the stuff, so it would be smart to replace those. Then I figure I should also replace the water pump and thermostat too. All that is almost another 300 in parts. And I still wouldn't be sure if it's all out of the coolant system and the lower sections of the block(2 piece block).

The car was 500. I'm already into it with parts for almost another 800. I still need to spend at least another 200 for a replacement motor mount and to get the exhaust fixed. Once running I'm sure it'll need another 100-200 in other stuff(service stability system message was on the dash). With the cooling system stuff I'll have just about 2,000 into this car. It would be my daily driver. I could return the parts ordered and part the car out and make my money back plus some if I decide to abandon this project. Then I'd go get another lease or explore some other options I have. My current lease is up in about a month so time is the major factor now.

Cut bait

If the car is nice, itd be worth it. not having a monthly payment is also nice as well as cheaper insurance.

From doing some more research, It does seems that the product is Bars leak stop "rhizex". Now the questions is how bad is the cooling system?

The car is ok, not perfect. a dent or two, pass side was repainted, cracking a little on bumpers, one rust spot by a wheel well, a cigarette burn on one seat, sagging headliner by back window.

Not sure what your goal is here, so I'm sorry if my response is off-base, but:

I don't know what the book value of the car is, but if you're trying to drive it for free then flip it for a profit, it's looking like you may have some trouble accomplishing that.

If you're looking to put money in your pocket through eliminating a recurring monthly payment & additional insurance, while still having a cheap and reliable DD, then I'd be okay with throwing a few more dollars at this car to make sure it's reliable. I imagine a 20 year old car has done most of its depreciating by now, so you may very well end up driving it "for cheap" (read: not free) when you look back in a year or so.

In any event, being in this car for a total of $2,000 isn't a terrible thing when you consider the other option you're entertaining (sinking $2,000-$4,000 a year on a lease payment and higher insurance).

With all that said, I wouldn't feel comfortable being in this car for $4,000 total, if that's the road future discoveries lead you down... I think you need to figure or what your goal is for whatever car you're going to drive in 2017 & then set an all-in budget to limit yourself.

The goal was always to eliminate a car payment and lower insurance cost.

I did a lot of searching the web about the leak stop and how to flush it out. It seems my main concerns are the radiator and heater core. The rad concerned me from the beginning a when I opened the drain and barely anything came out. A new one is 100-150 from rock auto, so that would be a given as to getting a new one and not trying to flush it out. The issue is more the heater core. Its buried behind the dash and requires the console, steering column and whole dash to come out. They say its a several hour task. I refuse to go that far. With the engine out, I can easily access the hoses going to the heater core in the engine bay so I will flush it as much as I can that way. After that its just cleaning up the rest, sucking it out of the water jackets, cleaning the overflow tank, flushing out the coolant crossover and water pump, and cleaning the heads. Once running I'd do a complete coolant flush to get as much more that I missed in the block. I think I could still keep total cost under 1900 bucks.

The desired life span of this car is 7-12 months. Anything more is great. I was never planning to flip the car for a profit, was always for me to just drive. I still have my dodge ram to drive in non-snow/rain weather.


Also, issues like this were not entirely unexpected. I knew stuff would come up on a 18 year old car. That's the reason I shopped around for the cleanest, lowest mileage sts I could find and set my purchase budget at only 500.

I would do a combo of low pressure compressed air and water to flush the core. Should help dislodge that crap.

Did you pull the codes for the stability light prior to disassembling the engine? The electronic shocks and struts for the STS's are extremely expensive IF you can find them. The cost of them alone may be more than the car is worth.

lol well.. I had planned on doing that but the battery was dead when I finally got around to work on the car and I completely forgot. So yes, thats a risk I'm taking, but I'd be in the same situation even if the head gasket fix went quick without any issues. I did previously research online on the forums and rock auto. Fronts are $625 each, and worst case, I deal with bad shocks for a few months or it gets non-electronic struts and I deal with the warning message.

Today I fabbed up a tip for my shop vac to clean everything out. Worked very good. I have a little more final cleanup to do in the water jackets and then it'll as good as new. I also flushed the heater core which seems to be fine so I'm not concerned about that anymore. I flushed out the overflow tank as well so thats good too. I also pulled the coolant crossover/water pump housing and I'll flush it out too. It'll be easy with it off the motor. All hoses are also off and will be flushed out when I get the time. I will be ordering a new water pump and radiator.

After fully researching how/where to coolant flows on a Northstar, I feel confident I wont have any future issues with the stop leak. It enters and leaves the motor through the coolant crossover assembly. it goes into the block, then up to the head then back into the crossover and out to the radiator. heater hoses come off the coolant crossover too. There are a few other small coolant lines which i can check and clean, but I'm not afraid of a hidden buildup of stop-leak anymore. So, I'm going to go ahead and fix it.

I just saw this on FB and just felt i had to leave it for you

I seen it too and thought about this

Yea.. Lol.

Today i just picked up my rebuilt alternator.
Of course they had to be different and make it water cooled...

hows this going? i see the thread is a few months old.

Its going fine, just limited time to actually work on it. Basically like 4-5 days a month, if that.

I cleaned out all the junk from the motor, drilled and tapped the block, installed the head stud kit, and put the heads and intake all back on. Right now I just have to finish up fabricating the y-pipe, install the harmonic balancer and mount the newly rebuilt alternator. Then the motor/trans can all go back in the car. Once that done, I still have to buy new spark plugs, a new radiator, water pump and brake master.

http://i32.photobucket.com/albums/d5...ps0so61tma.jpg
http://i32.photobucket.com/albums/d5...pslmxrstth.jpg
http://i32.photobucket.com/albums/d5...ps9fijcp9j.jpg
http://i32.photobucket.com/albums/d5...psnksdwbvn.jpg

not bad not bad ! GL

Question, did you do a cylinder leak down test, and did you have the heads checked for warpage. Wouldn't be suprised if someone went to long on low coolant and overheated it, and limped it along with the bars leak sealer knowing what the cost of a head and gasket job would cost.

It turns cadillac puts the pellets in from the factory and calls for them at every coolant change. From everything I've read online and even from the company I bought the stud kit from, no one has yet to see a warped northstar head. They overheat all the time and are fine afterwards.

I have the car back together, just need to bleed the brakes, change the oil, and charge the battery and it should be good to go. So we'll see in a few days how it really is.