Want to flush coolant on SDL - Page 2 - PeachParts Mercedes-Benz Forum

Brian Carlton · #16 01-05-2005, 12:24 AM

Quote:

Originally Posted by WANT '71 280SEL

Bought two bottles of the Prestone flushing agent. They also have a rust remover and cleaner for sale, but I just bought the flushing agent. I'm going to pour both bottles into the radiator via the top hose then top up with water enough to fill the rad and block, then run around and do some errands. I won't let it sit overnight or hardly even turn it off. Then, I'll go back to the shop (25 miles from my house exactly) and drain it out then keep flushing with water until the agent is out. Then, I'll add 1 gallon of straight antifreeze then top up with a mix. I don't know if the extra 1/4 gallon would matter much, but if it does, I don't mind.

I'm starting to feel like Carrameow.

1) You should not add the flushing agent to the system while it is full of the green stuff. You need to flush it first. You need to do this via the hose at the back of the head using the Prestone "flush T".

2) You can leave the flush agent in there for a couple of days if it does not drop below freezing. You need to drive it for some distance if you want to have the flush agent do what you bought it for.

3) You must flush the system several times and drive it between these flushings to ensure that all the flush solution has been eliminated.

4) You must drain the system for the last time and add 1.25 gallons to the overflow tank and/or the upper hose.

5) Fill whatever is remaining in the system with fresh water.

6) Drive the vehicle for ten minutes and allow it too cool. Top off the overflow tank with 50/50 mix.

Don't ignore any of the aforementioned steps if you want the job done properly.

WANT '71 280SEL · #17 01-05-2005, 08:25 AM

Now I see, I should drain the coolant first, which is what I though, then flush with water? After I've flushed all the green stuff out I can add the two bottles of flush and water then drive like mad for a day or so? It will definitely be around freezing here so I'll just keep it in for a full day of driving. I love just taking the SDL out and going around the backroads, etc. After I drain out the flushing agent I'll add pure water. I'll then drive, flush, five times. Should I maybe have bought the cleaner and used it after the flushing agent? It seems to have had the same directions on the back as the flushing agent. They both say to drive 4-6 hours with the flush/cleaning agent in there. If this process were to go over 1 day then I'd just leave it at work in the heated garage, wouldn't be a problem.
Thanks Guys. Sorry to make such a simple procedure drawn out here, but this is good info for the archives.
David

P.S.
If I undo the hose at the back of the engine, would I spray into the firewall or into the head?

Hatterasguy · #18 01-05-2005, 01:15 PM

I would caution against bothering a 18 year old hose, you will probably need to cut it to get it off anyway. Also that would be overkill anything left in the block will be drained when you drain the water.

Just drain the coolant and fill it with water to get the rest of the green out. A little left won't hurt anything you will get it the next time around. Heck it probably has had green coolant in it for 10+ years. Nobody ever seems to use the right coolant in any car.

Brian Carlton · #19 01-05-2005, 01:33 PM

Quote:

Originally Posted by Hatterasguy

I would caution against bothering a 18 year old hose, you will probably need to cut it to get it off anyway. Also that would be overkill anything left in the block will be drained when you drain the water.

I disagree. You are not going to get a proper flush on the engine unless you introduce fresh water into that hose at the back of the engine. You can remove the hose if you do it carefully and get it to break loose first.

The water should be injected using a flush T. The water will hopefully go through the heater core and out the bottom of the engine. However, I always wanted to experiment with clamping off the hose to the engine and forcing the water to go through the firewall to the heater core.

Hatterasguy · #20 01-05-2005, 02:12 PM

After fighting with and replacing some of the hoses back their I have yet to get one to come off without cutting it. The two hoses by the firewall also look expensive, I bet they are $50 each.

When I had water in my system for a few days I had the two small hoses way up under the windsheild out, they were full of water no coolant. With the engine running the water pump will do the rest.

But I had both the upper and lower hose off and the t stat out. I stuck a garden hose in where the t stat sits and back flushed the block, nothing really seemed to come out but my old coolant was clean. I think the PO used Dexcool.

If you keep the coolant clean you really don't seem to have to flush it. Dirty coolant causes the problems, and thats why those flush chemicals exist.

Brian Carlton · #21 01-05-2005, 02:23 PM

Quote:

Originally Posted by Hatterasguy

But I had both the upper and lower hose off and the t stat out. I stuck a garden hose in where the t stat sits and back flushed the block, nothing really seemed to come out but my old coolant was clean.

This procedure will not send any water up through the heater core. Now, if you are not overly concerned about a complete flush, then the discussion is moot.

However, when the acid cleaner is introduced into the engine, it is vital to use a procedure that will effectively get 98% of it out of the engine. Flushing the heater core is a necessity in this situation.

Hatterasguy · #22 01-05-2005, 02:27 PM

Ok good point, you wouldn't want to leave any of the flush in their. I was only thinking about a little coolant being left.

benzboy87 · #23 01-05-2005, 02:45 PM

Why couldn't you just drain the old coolant, turn the heater setting to "max", fill with fresh water, run the car for a while (until the thermostat opens) with the heater setting on max, let the car cool down, drain and repeat this process for several more times - like 3 or 4? After the last time you drain - fill with coolant and water, turn temp. on heater to "max" once again, watch for thermostat to open, add more coolant and water and button it up.
I can't see (unless there is major crud or has been a blown head gasket) any reason to add citric acid to flush the system.

Brian Carlton · #24 01-05-2005, 02:50 PM

Quote:

Originally Posted by benzboy87

Why couldn't you just drain the old coolant, turn the heater setting to "max", fill with fresh water, run the car for a while (until the thermostat opens) with the heater setting on max, let the car cool down, drain and repeat this process for several more times - like 3 or 4? After the last time you drain - fill with coolant and water, turn temp. on heater to "max" once again, watch for thermostat to open, add more coolant and water and button it up.
I can't see (unless there is major crud or has been a blown head gasket) any reason to add citric acid to flush the system.

That would be fine. It was my intention to circumvent the drain and repeat process by flushing the heater core directly.

However, I will say that I was not completely successful with this approach as evidenced by some green water that departed the engine with the flush solution. If I was successful, the water should have been clear.

WANT '71 280SEL · #25 01-05-2005, 06:33 PM

hattie, you know there is a tool for removing hoses that are stuck? It has a curves pick to it at the end. The one of my uncle's that I use is made by Snap-On and has worked great on my SD so far, so no worries about removing the hoses.

I'm going to removie the specified hose and spray water into the firewall side of it. Will I have any bad side-effects of doing it this way? I'll do that after I do the citric flush since the flushing agent will clean that out when the car is being run.
Thanks
David