T Stat / Coolant Flush Questions - PeachParts Mercedes-Benz Forum

dieseldan44 · #1 03-13-2007, 11:35 AM

Ive read through all of the archives on the subject...Ive never flushed a rad before...

I need to replace my t-stat since my car likes to run at 100C. Originally I was going to replace my GREEN coolant from the PO and do a citric acid flush, but I dont have time to get really involved with it right now. I want to verify the cooling system improves with the new t-stat first.

My questions are:

1.) Should I even bother putting in new antifreeze now if I plan to the do citric acid dance in the next two months? Im planning to just pour the green stuff back in for now. The car is not being driven daily at this point. As I said, I just want to see the temp go down.

2.) Is there some abbreviated flush procedure (no citric acid) I should follow for now?

3.)What do you guys do with your coolant? Where could I take it?

Thanks,
dd

retx · #2 03-13-2007, 12:32 PM

the coolant can be taken to any facility that recycles paints.
you can pick up a flushing t for .99 at autozone and a short piece of heater hose, install it so that it you can use a garden hose to flush the system after you drain it. do not mix types of coolant if you can help it. so clean the system well before replacing with zerex g-05
all zerex g-05 is identical in formulation regardless of dye color.

sokoloff · #3 03-13-2007, 01:00 PM

Most city water/sewer systems allow you to dump coolant down the drain.

connerm · #4 03-13-2007, 01:10 PM

"Most city water/sewer systems allow you to dump coolant down the drain."

Please tell me you are kidding or forgot the word "not."

DUMPING ETHELYNE GLYCOL is COMPLETELY WRONG and ILLEGAL

Instead of dumping it down the drain, dump it on your sofa. I don't want it in my water.

Submitted respectfully.

carnut · #5 03-13-2007, 01:13 PM

Make sure you check the radiator surface as well as condenser surface for road debris, bugs etc. That will cause restricted air flow over the fins. Usually you can wash the engine side of the radiator with a garden hose to dislodge the debris. Just spray towards the grille. Make sure you also replace the radiator cap with a new one to make sure its holding proper pressure. I prefer MB brand parts. One item often overlooked is the fan clutch. It engages at idle and low engine speeds to stabilize the eng. temperature. In California old coolant must be captured and taken to a recylcer. I take mine to a local new car dealers service dept.

DeliveryValve · #6 03-13-2007, 01:25 PM

Quote:

Originally Posted by carnut

Make sure you check the radiator surface as well as condenser surface for road debris, bugs etc. That will cause restricted air flow over the fins. Usually you can wash the engine side of the radiator with a garden hose to dislodge the debris. Just spray towards the grille. Make sure you also replace the radiator cap with a new one to make sure its holding proper pressure. I prefer MB brand parts. One item often overlooked is the fan clutch. It engages at idle and low engine speeds to stabilize the eng. temperature. In California old coolant must be captured and taken to a recylcer. I take mine to a local new car dealers service dept.

Good tips above.

In addition, I would change out the termostat with a Behr unit and flush the system out with a garden hose by sending water through one of the heater lines. Make sure you catch as much as the waste as possible and properly dispose of it. (Don't dump it down your drain)

connerm · #7 03-13-2007, 01:34 PM

Just changed out mine in my 95 606 last week. Two pieces of clear tubing attached to the rad. drain valve and one to the drain on the passenger side of the motor directed all old coolant into a container. I replaced the green stuff with the g-05 stuff. I didn't hose it out, so I'll probably do another flush and fill before too long. The g-05 from zerex is pretty cheap and with the draincock and engine block plug, it was really pretty easy to change. Fill through expansion tank. No need to remove upper hose on the 606. At least it worked for me.

DeliveryValve · #8 03-13-2007, 01:36 PM

Oh I forgot. I agree use G-05........ Good Stuff and cheaper.

vstech · #9 03-13-2007, 02:34 PM

Quote:

Originally Posted by sokoloff

Most city water/sewer systems allow you to dump coolant down the drain.

I also assume you have no problem drinking it? feeding it to your children? "heh, it's actually quite sweet" of course, it's totally poison, so your posts will be remembered
John

dieseldan44 · #10 03-13-2007, 03:03 PM

Thanks for the suggestions...I like the idea of a less labor intensive flush until I get more time / warm weather to do this.

any special tips for getting air out on the refill?

Quote:

I would change out the termostat with a Behr unit and flush the system out with a garden hose by sending water through one of the heater lines.

which line is this? near the back of the block?

sokoloff · #11 03-13-2007, 05:59 PM

See http://www.techguys.ca/howto/coolant_flush.html, about the second paragraph on proper disposal of used coolant.

I do not dump any toxic substances illegally or improperly. My last house had a septic system and it was illegal to dump used coolant into that system. I always took it to a quickie type oil place for them to dispose of it. All they did was dump it down the drain, because the city sewer system allowed it as long as it was well diluted. My current city sewer system also allows it. If they didn't allow it, I owldn't do it. All I'm saying is that you need to check with your local authorities to see what is and is not permitted.

Brian Carlton · #12 03-13-2007, 05:59 PM

Quote:

Originally Posted by dieseldan44

Thanks for the suggestions...I like the idea of a less labor intensive flush until I get more time / warm weather to do this.

any special tips for getting air out on the refill?

which line is this? near the back of the block?

There is a small hose that comes off the back of the head that is perfect for this. Just be careful with the garden hose pressure. You can overfill the system and pressurize it much higher than the design pressure and possibly damage the heater core if you run the tap wide open and pay no attention to what you're doing.

DeliveryValve · #13 03-13-2007, 06:25 PM

Quote:

Originally Posted by dieseldan44

Thanks for the suggestions...I like the idea of a less labor intensive flush until I get more time / warm weather to do this.

any special tips for getting air out on the refill?

which line is this? near the back of the block?

Yes on the the left side rear by the oil filter housing. First make sure you have the Climate Control on Heat before you turn off the car. With the car cooled I usually disconnect the hose end nearest the fire wall and hold the garden hose to that hose. As Brian said, make sure not to run full pressure. Then to catch the fluid, I like disconnecting the lower radiator hose and let it drain to a large drain pan. This pan fills up fast and have plenty of containers to empty it out.

To refill, I like to fill the system using the upper radiator hose disconnected from the radiator side. By holding the hose a little higher then the engine you can purg most of the air out in the block. Then I like to loosen up/remove the vacuum switch (careful because the vacuum connectors are very fragile) on the upper radiator hose neck housing to bleed the air out while refilling on the recovery tank. With the engine running and the vacuum switch is still loosened more air should purge out. Make sure you refill as necessary.

sailor15015 · #14 03-13-2007, 06:31 PM

If you have to replace the stat, try using a 75*C unit from a 1977 450SEL. I had terrible luck with the 80*C units for our cars. They wouldn't even start to open until about 85*C and would cause the car to run closer to 100*. This was with a new radiator, water pump, and a freshly flushed system. The new 75* stat keeps the temps rock steady at 82, where the old 80* stat used to before it failed closed and caused my car to overheat for thirty very intense seconds before I could turn it off.

dieseldan44 · #15 03-13-2007, 10:51 PM

Thanks everyone...replaced the stat today after work. Had to work fast before the NE darkness set in. I dumped in the old green coolant, promising myself that I will do the flush as outlined here ASAP.

Well - I put in an 80 c Behr stat and went for a 45 min drive - Temp now stays at 90 all the time, 85 if I put the heat on. From what Ive read this is perfect for an 80 c stat. Woo hoo. It's nice when things are easy like that.

Interesting sidenote - my old t stat had a hole in it STOCK. Maybe an 1/8" hold with a brass insert thing to dampen the flow a little bit, but it was defintely not an afternarket mod. The stat was some off brand, I forget the name now.