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I recently acquired a 2003 Regal with 160,000km on the clock and came across a coolant leak. Here is the store.
I was on my way home last night and punched it to pass, going about 100km/60mph, needless to say, it was my first time really punching it. Dropped gears smoothly, and got into the red zone on the tach immediately... Then there was a cloud behind me! I slowed down, got into the slow lane looking for a place to pull over but the cloud went away and I babied it home watching the gauges.

Once parked it was still steaming and upon inspection it is definitely coolant, and it is coming from the front of the engine, and from the looks of it under the exhaust manifold. I couldnt see actual fluid anywhere because of interferences, but the steam was a good indicator of locations. My initial thought is a freeze plug, but I have never heard of these going on these engine. While very possible as freeze plugs are just metal and everything rusts in this world.

Has anyone blown a freeze plug on a series II? It does have a block heater on it, where do they stick the block heaters on these things? hopefully in the most accessible spot, which i hope is what blew...

Appreciate the help!

As suspected:


The brass wing retainer was split in two, looks like it might have been over torqued. Will be replacing it this weekend along with the UIM and LIM.

One question I have is; what is the best method for clearing out the old dex-cool? I've read the reverse flush thread which i'll do, but the dex is caked on in the rad and in the reservoir. I tried cleaning the inside of the reservoir a bit already and its not letting go without physical persuasion. Just wondering if it will soon break down with new coolant and more heat cycles or maybe it'll just stay there forever.

I know haro posted somewhere how he cleans out the nasty coolant tanks, might have to do some searching.

That is definitely your block heater, you could just replace it with a standard rubber seal type plug if you want to eliminate the block heater and do the job cheaper.

I'd run hot water through it while the freeze plug is out of it.
The brown sludge loosens a little when heated up. I reversed flushed mine with straight hot water. Of coarse I have hot water in my garage, but you could also run a hose off your water heater if need be.
The more of the sludge you can get out of it the better off you'll be.

Thanks for the info guys.
I got a head of myself and disassembled everything before flushing. I can still do it once its all back together i guess.
Some highlights of the disassembly:

I wanted to vomit while doing this:

There was still more deep within the port, Using the shop vac was all I could do. I dont know how much more there was in there. This might have been the reason why my block heater blew out. This could have been restraining the entire system and causing excess pressure up until that point.

The gaskets, all 4 ports were shot:

One of them:

The left coolant port on the UIM has some coolant sneaking over, but the UIM was in good shape with no signs of failure:

Is this normal?? it was incredibly thick and greasy:

Some cleaning:


The new:

Not bad for 131 bucks!

I found remains of a previous coolant elbow replacement, but will be putting the aluminum ones in. I also have a new water pump, lower rad hose, and 180* thermostat. I would have preferred a 195 due to it being a winter vehicle, but its all they had.

Everything came apart real easy, took 3 hours to disassemble, but thats because I took a ton of pictures along the way. Just cleaning the TB took forever, including the LIM.

I've been toying with the idea on porting the LIM and heads...

All done, pretty straight forward, but took way longer than expected due to a snapped bolt in the timing cover while doing the water pump:

welding a bolt to was the only way to remove it. I tried PB over night, heat and vyse grips, twice, but to no avail. Third night I rigged up the welder and got it dialled.

and a snapped IAC bolt...
All these open ended thread boss' seem to be an issue on this car.

Nothing tiny drill bits couldnt handle and new M4 hardware:


also did some polishing:


and did the valve cover gaskets:



and painted everything:


all assembled:


Replaced the block heater too, which was straight forward.
Runs like a champ at WOT now, next onto wiring in some heated seats!