00 gtp cooling flush

2000 gtp. i noticed a smell of coolant recently, and checked the resevoir. it was pretty gunky, and was definatly dexcool. i read on this forum and others that alot of people dont like dexcool.i want to change the fluid, but i dont know if i should use dex, or regelar.also i know the systen should be flushed if im going to change coolant types. should i flush reguardless? what is the best way to flush change fluid? i noticed there are a bunch of vent or drain valves, that im not familiar with. which valves are for what?any help would be appreciated.i should also mention, the car is not running hotter than it should, but it is gunky none the less. tanks for the help

You can switch over to another coolant like Prestone Extended Life (yellow bottle). It is OAT based like Dexcool but fully compatible. Cooling system should be flushed when switching brands.

To determine how bad the Dexcool condition is drain some off from the radiator drain and inspect it. The mess you see at the reservoir is normal over a period of time due to exposure to air. The reservoir can be removed and cleaned out. Also remove the radiator cap when engine is cool and inspect in the filler neck area.

To flush Prestone makes a flush kit which connects to one of the heater hoses.

After flush all air from cooling system must be bled out. The bleed valve is located on the thermostat housing.

You can switch over to another coolant like Prestone Extended Life (yellow bottle). It is OAT based like Dexcool but fully compatible. Cooling system should be flushed when switching brands.

To determine how bad the Dexcool condition is drain some off from the radiator drain and inspect it. The mess you see at the reservoir is normal over a period of time due to exposure to air. The reservoir can be removed and cleaned out. Also remove the radiator cap when engine is cool and inspect in the filler neck area.

To flush Prestone makes a flush kit which connects to one of the heater hoses.

After flush all air from cooling system must be bled out. The bleed valve is located on the thermostat housing.

Hello Bob, thanks for the info. I have one question:

I just bought the Prestone coolant flush kit, and it states that it should be connected to the hose #2 (or heater hose). I took off the coolant reservoir and I can see the two hoses. Wich one is the one that needs to be connected to the "T" flushing connector?
Do I need to cut the hose, or just disconnect the hose from the block and plug the connector to the hose end?
The instructions said that one of the hoses comes from the firewall to the wather pump, and the other one from the firewall to the heater.
Any help would be appreciated :cwm27:

Hello Bob, thanks for the info. I have one question:

I just bought the Prestone coolant flush kit, and it states that it should be connected to the hose #2 (or heater hose). I took off the coolant reservoir and I can see the two hoses. Wich one is the one that needs to be connected to the "T" flushing connector?
Do I need to cut the hose, or just disconnect the hose from the block and plug the connector to the hose end?
The instructions said that one of the hoses comes from the firewall to the wather pump, and the other one from the firewall to the heater.
Any help would be appreciated :cwm27:

If you look at the firewall it will be the bottom inlet which is heater core input. The top is the output. Normally you tee in by cutting the respective hose and hooking up the tee adapter. Good luck!

Awesome Bob!!

Thanks, I'm on it right now :grinyes:

Another question....

After using the flushing the system (with the Prestone Flush bottle) how do I know how much coolant do I need to add? because the system is going to be full of water, If I add 50/50 I'm only going to get at the end about 30% coolant, no?
Or do I add coolant (50/50) untill comes out green out of the Tee?

Thanks again....

Another question....

After using the flushing the system (with the Prestone Flush bottle) how do I know how much coolant do I need to add? because the system is going to be full of water, If I add 50/50 I'm only going to get at the end about 30% coolant, no?
Or do I add coolant (50/50) untill comes out green out of the Tee?

Thanks again....

Once you are done flushing you can close off the tee adapter.

What I do after flushing is drain off as much water by opening the radiator drain plug. Since there will be water in the system you will not be able to calculate the proper 50/50 mix and only be able to guesstimate. The way around this is to premix to 50/50 using another clean container/bottle. I would not poor in pure coolant and attempt to figure it out. Also, use distilled water not tap water when you premix. I recall not using over 8 quarts or so of premixed coolant after a flush.

Sometimes it is better to buy ready to go 50/50 premixed coolant so you do not have to worry about the hassles of mixing.

After water is drained close drain plug. Poor in 50/50 coolant into the radiator filler neck until the level comes up. Then start engine with radiator cap off and let warm up until the thermostat opens, then top off radiator until full. Re-install radiator cap. Then make sure the coolant reservoir has sufficient coolant level. The last step is to make sure there is no air in the system by doing the bleed procedure.

Just to double check the coolant protection and mix you can get one of those cheapy cooling system testers. You can always drain a little coolant out later and then add pure coolant to get it to around 50/50.

To get the majority of the fluid out of the engine there are two block drain plugs. Not sure where they are on the 3.8L but if you use a mirror you can scan around on the front and backside of the block and find the plugs.

To get the majority of the fluid out of the engine there are two block drain plugs. Not sure where they are on the 3.8L but if you use a mirror you can scan around on the front and backside of the block and find the plugs.

That is easier said than done on a Series II 3800. It is not necessary for the trouble it will be. Just my two cents. :2cents:

When I drained the radiator on my 2000 SE (3100V6) I only got about 4 qts. The capacity of cooling system is 11qts. So if I were to use 100% antifreeze to refill radiator, the best I could end up with is about 4/11=36%, which is what the original poster said I think. Yeh, I could then drain that out, and refill with about 3 quarts of 100% and then top off with water and that should get me about 50% or I could do as was said before and put in 50/50 during flush and then stop when green is coming out, then fill the rest of way with 50/50 and this will be close. Just draining rad and filling with 50/50 will not get me close and would require many drains and refills since you are adding 50/50 and you want to end up with 50/50 but you are starting with 7 qts of water already in the system?

where do you get distilled water for this?

What is bleed procedure for my 3100? Looks like there is bleed screw (black) on top of a long tube that sits atop water pump and also one on other side of engine near the throttle body and I believe the thermostat housing (this one is brass).

If the thermostat isn't open, the bleed screw on the top of the thermostat housing won't do you any good. So when you're flushing the system and the engine is cold, you'll want to work the black screw near the water pump to bleed air from the system.

Your 3.1L has block drain plugs that are accessible. They aren't exactly right there to get an open-end wrench on, but with the right combination of extensions on a ratchet you can get to them. However, if you think changing the spark plugs is difficult then maybe you won't want to mess with the drain plugs. I think the spark plug replacement on both the 3.1L and 3.8L S/C motors is easy and getting to the drain plugs was more of a pain. It looks like they repackaged their AC line routing at some point after 97, because I saw a rental Impala (2005) that had the 3.4L and the block drain was much more accessible on it.

Oh and for distilled water, you should be able to find that at any grocery store in your area.

There are differences between the 3.1 and 3.4 but the block drains should be accessible on either one of those engines. I don't know if they are in the same locations though. On the 3.4L the front block drain is located right next to the oil filter housing and knock sensor. The rear block drain is located dead center of the block by the 3X crank position sensor. But the rear is a PITA to get to due to the transaxle housing and subframe crossmember. Even coming in from the top like doing the rear spark plugs is difficult and the exhaust is in the way. Also, the 3.4L does not have an air bleed screw on the thermostat housing so you have to use the sole air bleeder on the heater return line located on the top of the black metal tube at the water pump. To bleed air just hold the bottom half of the brass fitting with a 10mm open end wrench and undo the top fitting counterclockwise with a 7mm wrench to bleed air. I've got a '02 Olds Alero with the 3.4L and it is a lot easier to work with than the 3800.

Thank you all for the responses.

Well, after flushing the system I drained all the water that I could by opening the drain plug of the radiator. After a few minutes, I put the plug back and filled the radiator with 50/50 mix (Prestone Extended Life :thumbsup: ). Started the engine and here is were I got a little brave.....

I lose the tee adapter just enough so fluid would come out of the line. Lots of water come out and at the same time I was adding 50/50 to the radiator. When I saw green coming out by the tee adapter, I close off the tee adapter and top off the radiator.

I used more coolant than what I thought doing it this way, but it seems like it worked. Once the t-stat open up, I bleed the line ( It helps by jacking up the front end of the car) and that was it.

Today it took just a liitle bet from the reservoir and seems to be working "finer than frogs hair"!!! :grinyes: