when pulling the block drain, there is a washer! - PeachParts Mercedes-Benz Forum

vstech · #1 06-20-2007, 10:14 AM

pulling the block drain on a 617 is not easy! it's messy, and difficult to get to. I used a 19mm socket, and an impact universal joint, and about 24" of extentions and an impact wrench... the bolt came out pretty easy, the deluge of gunk and water pouring all over me... of course, I did not watch what came out with the bolt. however. I did pull the bolt over a piece of plywood... thank goodness! sitting on the board was the little aluminum washer. I reccomend getting new washer when planning a complete flush. I re-used mine.
WOW citric flush sure does clean up the passages! my hoses were totally BLACK inside after the flush, and the water neck and everything was pristine! cool!

SD Blue · #2 06-20-2007, 11:05 AM

John, I am planning this same task in the near future. Is that a 19mm hex bit? Also, I understand the block drain is just forward of the starter on the side of the block. Is this correct? Did you access this from underneath, the wheel well, or from above somehow?

vstech · #3 06-20-2007, 11:16 AM

yup, 19mm hex. just in front of the starter, I pulled the pass front tire, and reached up from below... kinda tight. but doable.

funola · #4 06-20-2007, 01:54 PM

John,

Can you go over the flushing procedure? What concentration of Citric acid and where to buy it? How long do you let it soak and is it done cold or do you run the engine? etc etc. As I recall reading somewhere, you also use tide detergent. What does that do?

300SD81 · #5 06-20-2007, 02:00 PM

I don't think there was a washer..? It was too busy having 100 degree coolant pour on my face to notice if there was one...

vstech · #6 06-20-2007, 02:34 PM

tide degreases the coolant passages. it is a must do first step.
ok, first I drained and flushed old coolant. second I filled with tap water. drove it around, flushed it again, drained all passages, block drain, rad drain, etc. disconnected the heater hose, and put a hose adapter in there to flush the block with direct water, also flushed the heater lines this way, also flushed the expansion tank, and radiator. I took out the thermostat, and took out the innards of the tstat and put it back in, so I would get easy flushing and flow without fully heating up the car. then put in a cup of dishwashing powder dissolved into a 2 gallon bucket of hot water, filled the system with this, and topped it off with tap water, drove this around for 30 or so miles. (man the car sure does stay cool with out the thermostat in place) drained this out all drains, flushed as above, filled with tap water, drove around 30 or so miles again, drained flushed again, and drained well, filled with 3 cups of citric acid powder from ebay... search for citric acid, bath bomb, soda fizzz etc... citric acid did it for me. anyway, topped off this solution with tap water, filled it to the top totally, drove the car around for 100 miles, let the car sit overnight, and all next day. drained out that afternoon, flushed and flushed and flushed, pulled out my makeshift tstat gasket, and replaced with new tstat, filled with proper distilled water/zerex G-05 and awwwaaaaay ya go!

vstech · #7 06-20-2007, 02:35 PM

Quote:

Originally Posted by 300SD81

I don't think there was a washer..? It was too busy having 100 degree coolant pour on my face to notice if there was one...

yeah, I am with you on that one! definately need to cool the car before pulling that plug! I started looking for the washer cause it was leaking on one of my drive tests... and I found it! there is indeed a washer in there.

lee polowczuk · #8 06-20-2007, 02:39 PM

just think of how many people just drain the radiator, re-fill and call it a day.

Congratulations on your work!

LUVMBDiesels · #9 06-20-2007, 02:41 PM

I pulled the plug from my 'extra' 617 just to make sure i had the right one. It is a 19mm hex bolt with no washer on it. When I pulled it on the car I put the car up on stands then went from underneath. no washer, but what a mess. I then screwed in a short piece of 1/4 inch galvanized pipe and attached my hose to that in order to flush the bock. I winder if anybody has installed a piece of pipe and maybe an elbow connector and capped it. It would make the next flush really easy...

funola · #10 06-20-2007, 06:49 PM

I wonder if vinegar will work since it is citric acid and water?

Have you noticed any difference before and after?

vstech · #11 06-20-2007, 08:36 PM

ARRRRRRRGGGGGGHHHHHHH!!!!!
still hits 100C... I did use a chinese tstat... that comes out tonight and in will go a new german tstat.

LUVMBDiesels · #12 06-20-2007, 08:37 PM

Before I flushed the 300SD, the temps would range from 95 to 100 degrees. After I flushed out the old antifreeze, did the Tide degrease, flushed that and put in the citric acid solution the temps go from 85 to 90! I drove about 100 miles with the citric acid, then pulled the lower radiator hose. the water was brown! I refilled with more citric acid and am driving it for another 100 miles before flushing and filling with G05.

I am doing the same thing on the 528e and it is making a huge difference on the BMW as well. She used to run hot and now she barely gets into the middle of the (crappy no numbers on it) gauge.

I am thinking about doing the same thing on the Suburban and replacing the DEXCOOL with G05.

Douglas.Sherida · #13 06-20-2007, 08:40 PM

Quote:

Originally Posted by funola

I wonder if vinegar will work since it is citric acid and water?

Have you noticed any difference before and after?

Sorry but vinegar is ~ 5% (volume/volume) acetic acid.

You want to use 10% (weight/volume) citric acid, aka 100 grams/Liter.

They are both weak acids, citric being the stronger of the two. A vinegar flush would smell horrible and be less effective in descaling mineral deposits. I'd be very surprised to find out that the acetyl group in vinegar would negatively impact the metals/plastics in your car, but you never know.

Douglas.Sherida · #14 06-20-2007, 09:01 PM

Quote:

Originally Posted by vstech

ARRRRRRRGGGGGGHHHHHHH!!!!!
still hits 100C... I did use a chinese tstat... that comes out tonight and in will go a new german tstat.

LOL. My 84 300TD did the same damn thing. Ran at 100C when I got it with green coolant and obvious scaling.

I drained, removed thermostat, flushed 2X with tap water, degreased, flushed 2X w tap water, descaled, flushed 6X with tap water, flushed 1X with distilled, replaced thermostat (Behr), refilled with 5.5 L of Zerex and the rest with distilled.

All flushes were done by driving it up near operating temp at least 15 min (45 descale and degrease) and with the defroster on full blast, which was hard since it didn't want to go over 80 with the thermostat out.

The difference in cleanliness is AMAZING!. All he brass/aluminum surfaces are free from scale and the hoses are black inside.

Final operating temp = ~ 97.

I'm convinced that there is air trapped in there somewhere, since my defroster heat is spotty. I need to check the integrity of the monovalve to be sure though.

I've got to swap out the temp sender as well, but I don't really suspect it.

The thing that nags at me is that it ran nice and cool under the heaviest loads when the T-stat was out. I may end up swapping out the T-stat from my 85 as well.

vstech · #15 06-20-2007, 09:02 PM

as good as I flushed it, I don't think I let the citric stay long enough. the fluid came out clear/slightly yellow... and my temps did not drop... I am gonna try another new better brand tstat... but since the temps actually went up... I may need to pull the water pump too... I hate to waste all that G05... I can save some of it... Hmm. and as the temps with the tstat out never got much above 60C I really think it's the Tstat this time... who knows.