Northstar Engines and System Technical Discussion Discussion, HOW TO: Change surge tank (and coolant) on a 96 VIN Y DeVille in Cadillac Engine Technical Discussion; Driving to work in May one morning, I was greeted with the CHECK COOLANT LEVEL message on the DIC. After ...
HOW TO: Change surge tank (and coolant) on a 96 VIN Y DeVille
Driving to work in May one morning, I was greeted with the CHECK COOLANT LEVEL message on the DIC. After monitoring my cold coolant level in the tank for about a week, I definitively concluded that my coolant level sensor was bad. As a result, I ordered a surge tank and replaced it (along with the coolant) the second weekend of August. Here's how I did it, with pictures!
Make sure the car has been sitting for awhile. This allows you to get to things without frying your hands.
First, remove the plastic shroud atop the radiator frame. This will allow access to the radiator petcock.
Thus you are at this point:
If you have baseball mitt hands like yours truly, you can get to the petcock easily this way. Reaching down on the right side of the fan (as seen here) allows access to the petcock. To make it easier to loosen, try and power wash the lower driver's side corner of the radiator to remove any possible gunk on the petcock.
Drain the coolant. What I found useful is to start the engine and rev it gently. This helps remove the coolant without baking the engine. After about a minute, turn the car off. Use a shop vac to remove the rest of the coolant, because it will not drain completely on its own.
Next, remove the battery. This gives you access to the surge tank.
You will need to lossen bolts at the following locations:
Connecting the surge tank to the right front fender:
Connecting the surge tank to the right side of the engine bay:
The top feed into the surge tank:
And the drain out the bottom of the tank:
(This is pretty much right below the top feed in).
Furthermore, there is a brace that holds the a/c compressor to the surge tank. You will need to remove two bolts on the front side of the tank. These are right in front of the compressor.
Lastly, as you pull the tank up, be sure to remember to disconnect the coolant level sensor wire.
Assembly is the reverse of taking it apart.
Now that you have everything buttoned up, let's get some coolant back in her and get her back on the road!
What I fould helpful is to get a 5 gallon bucket for mixing. This gives you all kinds of room to do so. Once you have your brew formulated, use a funnel to pour the mix into the coolant bottles. Makes filling the tank WAAAAAY easier.
Use whatever coolant you like in a mix between 50-50 and 70-30 (coolant to DISTILLED water, respectively). Distilled water ensures that you don't gunk up your system, and the ratio range ensures proper protection.
FWIW, I used a 67-33 DexCool to distilled water ratio.
Fill the surge tank to about half full.
PER FSM: start engine and cycle engine speed from idle to 3000 RPM and back. Do this 5 times. Chances are you'll get the CHECK COOLANT LEVEL as the coolant circulates and purges air from the system. Fill the tank back to half and repeat as necessary. I only had to do it twice IIRC.
If you just want to change your coolant, follow the instructions on removing the old stuff and getting new stuff in there. Worked well for me, but feel free to modify as you see fit.
Congratulations! You have replaced the surge tank and/or coolant!