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2003 CTS, 2003 CTS, 2006 STS
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Discussion Starter #1
Hey everyone,
Ive got an 03 cts thats leaking coolant like crazy, so im going to replace both headsand im wondering if i should go with the same stock heads or upgrade to something better than stock? Also I am wondering what are some good upgrades to do to the engine and the air system?
 

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2003 CTS 3.2L, Luxury Sport, Diamond White
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659 Posts
Altonk said:
Hey everyone,
Ive got an 03 cts thats leaking coolant like crazy, so im going to replace both headsand im wondering if i should go with the same stock heads or upgrade to something better than stock? Also I am wondering what are some good upgrades to do to the engine and the air system?
I've got a slight coolant leak on my 03 as well. As far as I know, it seems the issue is generally a leaking water pump from what I've read on other threads. I'm taking it in tomorrow to a mechanic to have various things worked on and I'll let you know how the coolant thing goes. I'm also getting the timing belt replaced as a preventive measure, having the tensioner looked at, parking break fixed, and the brake lines checked.

Normally I'd try to tackle some of the work myself, but I recently moved to a place with no garage, it's 25 degrees out with a few feet of snow, and I don't have all the tools....
So...to the mechanic!
 

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'05 CTS-V
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8,045 Posts
Hey everyone,
I[‘]ve got an 03 cts that[‘]s leaking coolant like crazy, so [I’]m going to replace both heads...
Why would a coolant leak prompt you to replace the heads? :confused: I could see replacing the head gaskets, in the unlikely event that the coolant was leaking from the HGs, but replacing the heads seems like an awful lot of effort and expense for no reason.

...and [I’]m wondering if {I} should go with the same stock heads or upgrade to something better than stock?
You're not going to find anything other than stock heads. You could conceivably buy some used heads (ebay, car-part.com, etc) and find a machine shop that will port them for you. Some basic porting and polishing and a 3-angle valve job would probably net you some reasonable gains, but it’s awfully hard to predict any numbers since very few folks (maybe nobody?) has ever tried to build up a 3.2. Getting beyond the basic clean-up of the heads into more significant porting becomes a mix of art and science that involves trial and error – hence the reason that folks are still tinkering with and improving head designs on small block Fords and Chevys despite a few decades of work and millions of engines.

Also I am wondering what are some good upgrades to do to the engine and the air system?
Just like any other engine, improving airflow in and out of the engine will make more power. Headers, cams, freer-flowing intake manifold, larger intake tubing, etc etc. Unfortunately, as with the discussion of cylinder heads above, you won’t find much of anything in the aftermarket for the 3.2, and you’d also have to figure out tuning the ECU to take full advantage of the improved airflow. I don't know if there is any support for the LA3 in HP Tuners or any other tuning software.
 

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2003 CTS Luxury/Sport package
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722 Posts
stoveguyy said:
Altonk, where is coolant leaking? External leak? Or is motor burning coolant?
I have a coolant leak somewhere only problem is I don't visually see any coolant leaking. But I can smell it burning, I just changed my valve covers with new ones and gaskets but still burning coolant somewhere. Which at first i thought was oil burning btw. Any ideas?
 

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2003 CTS, 2003 CTS, 2006 STS
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Discussion Starter #7
Yea sorry i meant the head gaskets.... Because my dad seems to think that the coolant is leaking and coming put the head gaskets because we can smell it. Even outside of the car you can smell the coolant burning when its not running.
 

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Platinum 2001 Cadillac Catera Sport
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1,840 Posts
I know this thread is over a year old but I recently learned this info from the Omega Owners Forum (OOF). A little backround first. The 3.2 liter LA3 V6 in the 2003-2004 CTS is an upgraded version of the GM 54° V6 used in the Omega B, Saab 900, Saturn L series, and the Cadillac Catera. That's where I come in. The following is geared to using this engine in a Catera so you can ignore the portions dealing with the exhaust manifold, front pipe, and oil pan. They only pertain to fitting the 3.2L V6 into a Catera.

While visiting the OOF site I stumbled onto an easy, relatively cheap way to add more horsepower to the Catera. It can be accomplished with stock GM parts (Cadillac/Opel/Vauxhall/Saab/Saturn), and centers on using the 2003-2004 CTS 3.2L V6, plus parts from our Catera's 3.0L V6, and the Saab 2.5L V6.

According to Marks DTM Calib of OOF, we use a 2003-2004 CTS 3.2L V6 as the core long-block (with the 3.0L's oil pan), swap a pair of 1993-1998 Saab 900 2.5 liter V6 heads onto it (using the 3.2L's head gaskets), and the 3.2L's exhaust manifolds (they're formed steel instead of cast iron and internally wider). That requires using the "front pipe" from the Catera (the length of exhaust pipe between the manifold and the catalitic converter), modified to match the CTS manifold with some grinding of their flanges. The stock 3.2L has a 10.0:1 compression ratio and produces 220 HP. Replacing its heads with the 2.5L's (smaller combustion chamber) will raise the ratio to approx.10.8:1. That plus changing the 2.5L's cams to 3.0L/3.2L cams will increase its power & torque output by 20 to 30 HP. Add that to the 220 HP of the standard CTS 3.2L V6 and we can expect to see between 240 to 250 HP.
[notes 1,2,3]

The heads from the 1993-1998 Saab 900 2.5 liter (B258I) V6 must be ported slighty to mimic the contours of the 3.0L head's intake passages so to match the 3.2L/3.0L airflow specs. Swap the 2.5L's intake and exhaust camshafts with 4 intake ("G") camshafts from the 3.2L or 3.0L engines (both motors use the same intake camshafts). Those cams plus the exhaust valves from either the 3.0L or 3.2L (sodium filled for better heat transfer) are the hot set-up (British Police Omegas used the 4x"G" cams for an approx. 18HP boost).
[note 4]

Use the Catera 3.0L's fuel delivery setup (injectors, fuel rails) and the 3.7 Bar Fuel Pressure Regulator from the CTS. The Catera's stock ECU and sensors will work fine with this hodgepodge engine and though it should be safe to use regular grade gas, I suggest mid to high grade gas. It will protect the pistons, and exploit the increased potential of the engine.
[note 5]

At this point you could convert to an external oil cooler to avoid problems with the internal cooler leaking, pop in a new thermostat, replace the camcover gaskets or switch to Saab aluminum camcovers, convert to a spin-on oil filter, move the HBV to an more accessible location, and replace the Timing Belt & Serpentine Belt as well as their Tensioners.

Next, reinstall the ancillary equipment (Alternator, AC, PS, intake stacks & plenum, etc,). There is a large twin-bore throttle body available from The UK or go crazy, chuck the entire intake assembly altogether, and install 6 individual throttle bodies with air-horns. If you still have money left over there are aftermarket performance camshafts, a lightened balance pulley, an uprated 4 bar Fuel Pressure Regulator, even a cooler rated thermostat. Maybe more if you check some German sites and understand the lingo. Follow the links below.

http://youtu.be/Iityro35mYk
http://www.jenvey.co.uk/home/throttle-body-kits/jenvey-dynamics/opel-vx-v6-sfs42-throttle-body-kit-ckvx06
http://www.courtenaysport.co.uk/v6-tuning/info_21.html

RECAP:
  1. 3.2 Liter - Engine Block w/ all its internal parts, Exhaust Manifolds, Fuel Pressure Regulator, and Head Gaskets
  2. 3.0 Liter - Intake Plenum, Velocity Stacks, Fuel Delivery System, Throttle Bodies, TPS, Intake & Exhaust Cams, Exhaust Valves, Oil Pan, ECU, Sensors, Ancillary Components, and "Front Pipe" (modified flange)
  3. 2.5 Liter - Saab 900 Cylinderheads (intake passages require porting)
After all this we end up with a 200cc displacement increase, a stronger crankshaft, a higher compression ratio than the stock 3.2L, the best camshafts, the best fuel delivery set-up, freer flowing "factory headers", and an increase in horsepower anywhere from 20 to 30HP over the 220 HP of the stock 3.2L V6 plus more useable torque, all with stock GM parts. Sounds easier than swapping in an SC3800 V6 or an LS1 V8, doesn't it? True, not as powerful than either of those two but with them you'd have to do lots of custom fabrication, and maybe install a stronger transmission.[HR][/HR][HR][/HR]

NOTE 1: Placing the 3.0L heads on the 3.2L block will raise the compression, but not to the 10.8:1 ratio. I would guess to approx. 10.4:1.

NOTE 2: Placing the 3.2L heads on the 3.0L block will lower the compression below 10.0:1. I would guess to approx. 9.5:1.

NOTE 3: Placing the 2.5L cylinderheads on the 3.0L will raise the ratio above its stock 10.8:1 and could lead to predetonation (pinging) and damage (holing) the pistons, even if using high octane gasoline. DO NOT DO IT!

NOTE 4: All 3.0L Catera V6s have "G" intake cams and "A" exhaust cams. All 3.2L CTS V6s have "G" intake cams and "J" exhaust cams. Using "G" intake cams as exhaust cams instead of "A"s or "J"s will increase torque and push more of it up into the mid-range, but you don't gain as much off idle. Good for passing manuvers but not so much for stop-light drag-racing.

NOTE 5: The 2.5/3.0 had a 3bar and the 3.2 had a 3.7 bar Fuel Pressure Regulator. Upping the fuel pressure will not give extra HP, but it might give slightly better fuel atomization for a better burn, and if you were struggling to fuel it when floored it could help there.

NOTE 6: I cannot guarantee this engine will pass emissions testing. If that is a requirement in your state it may fail.

REMEMBER: These mods are based on OOF experience with the European versions of the GM 54 degree V6 engines. As far as they know they should be identical to the engines available here. I'm confident these mods will work, but as always, try these mods at your own risk.

The stock L81/X30XE 3.0L V6:
Cylinder bore 86mm
Piston stroke 85mm
Organic fiber head gaskets
Cast iron exhaust manifold

The stock LA3/Y32SE 3.2L V6:
Larger Bore - 87.5mm
Longer stroke - 88mm
Steel mutlilayer head gaskets
Forged steel crank (stronger)
Larger diameter exhaust manifolds (formed steel)

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Better late than never? My Catera uses a similar engine to yours and we have a coolant leakage problem with the Heater Bypass Valve behind the engine, under the wiper cowl. When it goes it leaks coolant on hot metal and evaporates without ever puddling but giving off that tell-tale odor. The CTS valve is pictured below.

 
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