96 Cutlass 3.1L water pump & coolant

[Jackson55]

Hello,
The water pump on my wife's car is leaking and I had a couple of questions maybe you all could help with.

1996 Olds cutlass supreme, 3.1L, 55K, been in family since new, original dexcool orange coolant.

Looks like the water pump is leaking at a pretty good clip. It appears to be leaking at the shaft seal, running down the inside of the pulley and then spraying all over. I don't see or feel any indications of a manifold leak at the back of the engine.

I’m aware of the dexcool controversy but am undecided as to whether to replace with same or switch to green at this time?
I’m aware of the safety issues with pets and coolant.

I had planned on flushing the cooling system within the next 10K miles because of the dexcool fears but it looks like I might as well do that now since I have to replace the water pump.

I have flushed cooling systems before but it’s been years ago when cars were much simpler and they actually had room to work on them. In the old days I’d put one of those t-fittings in one of the heater hose lines (can’t remember which one of the two was used…). I’d remove the radiator cap, start the car and let it come up to temp, turn the heater of full blast, hook the garden hose to the t-fitting and turn it on (not full blast) and let the system flush until the water coming out of the top of the radiator was clear.

I would then drain down the radiator a bit and put a gallon of antifreeze in until full. I’d check the mixture with an antifreeze tester but it usually worked out about right with the water that was still in the block and the antifreeze added to the radiator.

Not sure if you can still do it this way on these new cars or not. I read the Chilton manual and looked around the engine bay and have the following observations…

- The manual says to drain the block and remove the thermostat before flushing. I don’t recall doing either of these in the old days…

- The thermostat housing appears to be conveniently positioned directly behind the exhaust crossover tube that connects the front exhaust manifold with the Y-pipe at the back of the engine. It is so close that I see no conceivable way to remove that housing without removing part of the manifold/exhaust system.

- There is very little use of rubber heater hose on these engines, all long runs are done with metal tubes and just little short pieces of heater hose are used for transitions and connections. Given that, I see only one spot where I “might” be able to install one of these t-fittings in the short section of rubber hose which is in the run between the water pump and heater core. It's the top one coming out of the heater core and going to the thermostat and then of course the large rad hose from the thermostat to the top of the rad.

- I’m worried about using the cold water from the garden hose and the aluminum parts on these engines today?

So my questions are:
1. Since I have to replace the water pump should I flush the system before I install the new pump or after? Should I flush the system, then drain, then replace pump?

2. What flushing procedure should I use?

3. Which heater hose should the T-fitting be installed, the one going from the heater core to the thermostat? What if I can't get a t-fitting on the short section of rubber hose?

4. Any concerns with using cold water out of the hose for the flushing procedure? What if I used hot water from the tap/ house hot water heater?

5. Where exactly are the block drain plugs on this engine? I see a couple of possibilities on the front but am not sure if they may be oil passages. I can't hardly even see the back of the block given the frame members and how the engine is stuffed in there.

6. Would you switch over to green coolant at this time? I know you don't want to mix the two, so I wonder if the above flush process would be sufficient to get all the old dexcool coolant out?

Thanks

Edited to add pictures:
might this be the dreaded dexcool sludge?




This is the front of the block, are either of the two lower plugs a block coolant drain? There is also a plug above right of the oil filter but it is much smaller and I think maybe an oil pressure port.


This is the only hope I see of installing one of those flush t-fittings. This hose connects to the top heater core on the fire wall.


That metal tube goes to the tower thingy on top of the water pump.

[xeroinfinity]

welcome to AF.

I'll try to make this short.....

If the car hasnt had the cooling system flushed in the last 2-3 years it is time. I wouldnt bother with installing a "T" fitting unless you want to power flush the heater core.

If you remove the thermostat to do the flush you dont have to wait for the engine to warm up everytime you rinse and it makes it faster.
You can drop the cross over heat shield to access the thermostat. It can be done with out removing the heat shield, but its teedious. Should be 1/2" or 12-13mm bolts.

It might flush better with hot water but I'd use distilled water to fill or the 50/50 mix coolant.

You radiator cap.... looks like Dex and oil....

After removing the thermostat, I'd start with draining the radiator from the drain, either on the bottom or the lower rear side of the rad.
If that doesn't open or is broken, drain it fron the pass side lower rad. hose.
I think that is a block drain by the starter(in ur pic), one on each side of the engine block in the same local.

Looks prety dirty I'd use 2 bottles of flush!!
It also doesnt hurt to let the cleaner run a little longer then what the bottle states.

Then its just a matter of filling, running the engine to circulate cleaner, drain, then refill and circulate. Probly should rinse 4-5 X to get out all the cleaner.

I would also stay with Dex, mainly because of the multiple alloys in the cooling system system, and it does protect your engine from a higher and lower temps.

Then you will need to bleed the air out of the system when you are refilling the coolant. This can take some time, the bleeder is in your last pick above the rad.

Hope that helps, and sorry for the delayed reply !