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2003 Head Gasket Repair

24K views 241 replies 15 participants last post by  sts 03 
#1 ·
I have a slow coolant leak that I'm still trying to find but I think it may be the crossover manifold gasket.I have no puddles under the car and really can't find coolant dripping.I do see dried dexcool specs everywhere and it looks like there is a lot of dried dexcool on the bottom crossover gasket closest to the water pump but its hard to see in there.I need to pressure test first to see for sure.I know the 2000+ engines are know for leaking at the crossover gaskets.my main question for now is it even worth trying to use the bars leak or is that just a temporary fix if it even stops the leak?
 
#3 ·
Re: 2003 sts coolant leak (possible crossover leak)?

As much as I don't like that stuff, Bars might work in this situation. I would only even consider it because of the difficulty of replacing crossover gaskets, but if you do, DO NOT go crazy. More is not better. 3-4 tabs at the most.
 
#5 ·
Re: 2003 sts coolant leak (possible crossover leak)?

Replacing the crossover gaskets in our engines is a minimum 8-hour DIY job with a strong back and an advanced set of shop tools.

Cadillac shop labor alone is 4.3 hours and that's with any special tools needed.

It can be done in a heated garage, but it's no fun at all.
 
#14 ·
The reason the crossover gaskets leak is that the plastic forms that hold the shape of the seals, and fills the small gap between the crossover and block/heads, begins to crack. Once it fails, coolant pressure will have no problem pushing the seals out of the way. Leak stop has no chance of stopping that, and it will leave you on the side of the road.
 
#18 ·
Yea I remember the three bolts when I changed my plenum last year just couldn't remember if the tb separated from crossover , its hard to tell with all the dexcool drying up everywhere.what's the best way to clean all the dried dexcool up when I take everything apart and can the throttle cables be left connected to the tb or do the throttle cables have to come off tb when changing crossover gaskets?
 
#22 ·
Re: 2003 STS coolant leak (possible crossover leak)?

I had a similar leak in my 2002 STS recently and found that it was waterpump cover. When pressurized the system, I could see coolant dripping under the car, it was difficult to tell where it was coming from but when I put a paper towel under the cover, it got soaked and the dripping stopped. GM sells the whole new style assembly (cover, gasket, thermostat housing and new thermostat), I think was around $100. It took a couple of hours to install, there is another pipe on the engine that you have to remove to get to it, you need to replace a gasket on that as well. If you nee any additional info let me know.
 
#25 ·
I'm about to start getting everything I need ,10&13 mm flex wrench, do I need a tool to disconnect the fuel lines? What about changing the water pump gasket and seal , is that something that should be done as a preventive? Anything else I'm missing except time?
 
#26 ·
Yes? You'll need a fuel line disconnect tool. Any parts store, cheap.

The water pump/cover is nice and easy to get to with the crossover out, and gaskets are cheap. Personally, I would. Replacing the pump seal/O ring means you'll have to remove the pump, so you 'll need the pulp removal tool. I would suggest either replacing just the cover seal, or go all out and replace the pump as well.
 
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