Page 1 of 2 1 2 LastLast
Results 1 to 10 of 19

Thread: Coolant Flushing

  1. #1
    2 Star General
    Join Date
    Nov 2008
    Location
    Teton Valley, ID
    Posts
    672
    Thanks
    71
    Thanked 186 Times in 110 Posts

    Default Coolant Flushing

    Need some advice on a total cooling system flush.

    I removed several of the small hoses and drained the coolant. Opened up the drain cock on the bottom of the radiator and drained all that. Pulled T-stat housing too. Put the hose with running water in every open hose and let the water run for a long time, until clear. Drained radiator totally. Left everything drain for a while and re-assembled hoses and T-stat.

    Put in new Anti-Freeze, first straight (1.75 gallons), then 1:1 mix of anti-freeze and distilled water. I let the truck run with rad cap off for a bit. Buttoned it up and took it for a ride to open the T-stat (would never get hot enough idleing to do it). Removed the cap (after it cooled) and found the new coolant rusty and very weak. I figure there was some water hiding in the system somewhere and diluted it.

    So I guess I'm draining the radiator again. It there any way to get all the water out of the system? Do I just fill it with water only, drive, drain and repeat until it stays clear?

    I didn't know about the coolant drain on the rear right side of the engine until a few minutes ago. I'm assuming I should open that too and just run lots more clean water through it.

    Any advice would be greatly appreciated.
    1942 Dodge WC-1 Project Truck

    1990 M923A2- Sold

    19?? M35A2 W/W- Sold

    1973 Steyr-Puch Pinzgauer 712M- Swiss: SoldUnsoldFor SaleSOLD

  2. #2
    Moderator Warthog's Avatar
    Join Date
    Mar 2008
    Location
    OKC, OK
    Posts
    13,793
    Thanks
    1,521
    Thanked 5,530 Times in 2,745 Posts

    Default

    Per the -10 Operators manual the cooling system holds 28-32 qts or 7-8 gallons. The engine will hold at least half of that after draining. I would use straight coolant to refill.

    Cleaning the system is an exercise. An old school trick is to use Cascade dishwasher detergent to clean the system. The new stuff doesn't work as well as the old stuff. See if you can find the commercial grade stuff.

    Drain, fill, run and repeat is the best way to do it as there are many nooks and crannies where junk collects.
    Last edited by Warthog; 08-29-2014 at 16:57.
    "We are all born ignorant.....but one must work hard to remain stupid" - Benjamin Franklin

  3. The Following User Says Thank You to Warthog For This Useful Post:

    Merc1973 (12-07-2016)

  4. #3
    2 Star General
    Join Date
    Nov 2008
    Location
    Teton Valley, ID
    Posts
    672
    Thanks
    71
    Thanked 186 Times in 110 Posts

    Default

    That seems about right, I only got about 4-5 gallons total in it.

    I did run some CLR cleaner through. I'll flush it again and just add straight AF this time.
    1942 Dodge WC-1 Project Truck

    1990 M923A2- Sold

    19?? M35A2 W/W- Sold

    1973 Steyr-Puch Pinzgauer 712M- Swiss: SoldUnsoldFor SaleSOLD

  5. #4
    2 Star General
    Join Date
    Nov 2008
    Location
    Teton Valley, ID
    Posts
    672
    Thanks
    71
    Thanked 186 Times in 110 Posts

    Default

    I drained the radiator tonight. Ran the truck with cardboard over the radiator and the throttle opened a bit. That was enough to get coolant flowing through the T-stat. I ran fresh water through it for about an hour and half before it got clear! Can't imagine how many gallons of water went through it! I didn't mess with the drain on the block, it didn't want to open and I wasn't pushing my luck. After it was good and clear for a bit, I shut everything down and let it drain out as much as possible. I added about 4 gallons of straight anti-freeze. That seems about right. I ran it some more with the cap off, but didn't get a chance to drive it.

    I've read some of the posts about using distilled water (always did that in cars). I bought 4 gallons to use in my first attempt. I don't see how you could. You would have to have a tanker full to keep it flowing through! I guess I am over thinking it. The coolant looks much, much, better than it did before. Hope I am done with that chore for a looooooong time.
    1942 Dodge WC-1 Project Truck

    1990 M923A2- Sold

    19?? M35A2 W/W- Sold

    1973 Steyr-Puch Pinzgauer 712M- Swiss: SoldUnsoldFor SaleSOLD

  6. #5
    4 Star General Jeepsinker's Avatar
    Join Date
    Aug 2013
    Location
    Dry Creek, Louisiana
    Posts
    5,032
    Thanks
    1,028
    Thanked 1,803 Times in 1,027 Posts

    Default

    Drive it on a couple of moderate trips and you'll have to do it again. The best way to keep a cooling system clean is to never let it get rusty in the first place. Mine is not rusty but I flushed it a month or so ago anyway. I cut off the end of a water hose so I could connect it to the heater hose fittings. Backflushing it that way works fairly well. Just leave the cap off and let all the trash flow up and out. Flush through both fittings for best results.
    I sink Jeeps... That is all
    1969 Kaiser Jeep M35a2 w/winch (Daily driver, no joke)
    Now a hot rod deuce: LDS 465-1a, Waterloo overdrive, 2 micron fuel filtration installed, riding on 11.00r20s
    1: 84' M1008
    3: 87' M35a2c Air Force trucks (for sale)
    1: 91' Bmy Harsco M931a2(for sale)
    1961 M422a1 Mighty mite ser.#1580 (needs restore)will trade!
    1991 BMY M936a2 wrecker
    2: M1061 flat trailers
    2: Fresh rebuilt and load tested good Mep003a gensets(for sale)
    I do Fort Polk and other recoveries in my state. I can be reached at 337-401-2470

  7. #6
    dumpsterlandingfromorbit! gimpyrobb's Avatar
    Join Date
    Dec 2005
    Location
    Cincy Ohio
    Posts
    27,184
    Thanks
    2,340
    Thanked 8,278 Times in 4,350 Posts

    Default

    There is also a drain under the intake manifold towards the front. After pulling the heads on my deuce, I have decided I am going to install a coolant filter. This will be after I get the radiator fixed(shroud came off) and flush the system real well.

  8. #7
    4 Star General welldigger's Avatar
    Join Date
    Sep 2012
    Location
    Benton LA
    Posts
    2,600
    Thanks
    73
    Thanked 630 Times in 453 Posts

    Default

    After running it hard for a while with coolant flush I stuck a hose in the rad cap and opened all of the coolant drains. Rad, block, and heater core. I let the truck idle with fresh water being fed in while leaving all ports open until clear water was coming out of all of them. I then shut the truck down and let it drain. Then added fresh water and coolant. Granted my cooling system wasn't really dirty to begin with.
    "Turning pipe to the right"

    1972 Am General M35A2- Most common question-What do you do with it? My most common answer- Get ice cream.

    "I don't always downshift, but when I do its next to a Prius so the driver can hear me hurt the environment."

  9. #8
    Private
    Join Date
    Aug 2016
    Location
    Youngstown New York
    Posts
    9
    Thanks
    4
    Thanked 7 Times in 5 Posts

    Default

    M 35 flush. I just wanted to say thanks for the prior posts and info. ill add what i experianced if it helps anyone. I blew my lower hose so decided to do a flush at the same time. I took the advice of not using the NAPA hose and using one from a surplus supplier. I used one from Big Mikes. its shape was the same the lower leg appeared a tad longer. After test fitting I trimmed 1/2 inch off the lower leg to the rad so the back side didn't rub on the bracket behind the hose. I initially installed the hose without the inner spring from the old hose so I could easily pop it off several times when flushing it to drain it. I used irontite Thoro flush. It looked like powdered cherry cool aid. I filled it back up ran it 15 mins and dumped the water via lower hose. The mess was red and lots of rusty water. I refilled with water and ran it. I blocked the rad so it would heat up and drove two miles and got it up to 190 ish on the gauge. this time when dumping it it was even dirtier. I could still see a hint of the cleaner color so I did it again. I wound up filling running and dumping it 6 times to get clear water when draining. The last time I cracked the heater pet cock and let that piss until there was no trace of cleaner color, just clear water. I saw that it was posted that the capacity was 32 qts and several had problems getting over 20-22 qts when filling. so I figured I would start with 4 gals 16 qts of straight antifreeze first to make sure I got enough in. It took the 4 gals only. I had to run it shut it down for a while and re start it later to get one more gal in which makes 20 qts added similar to what others said. I hope the pics I added show up. Iam glad I added the antifreeze straight and not mixed or I wouldn't have been able to get the 50/50 mix in the end. Iam retired know so plan on driving and playing with the trucks. Thanks for all the good info from all here it really helped me.0[2].jpg0[1].jpg

  10. The Following User Says Thank You to Larry Weibert For This Useful Post:

    russojap (11-08-2018)

  11. #9
    4 Star General frank8003's Avatar
    Join Date
    May 2012
    Location
    Ft. Lauderdale, Florida
    Posts
    2,952
    Thanks
    1,980
    Thanked 3,950 Times in 1,405 Posts

    Default

    A filter can help, I used a mobile one because it won't break down.
    Lots in here about coolant filters. I bought one new valve, hard to work down in generator area, was forced to cut out the original valve down there. Note this truck has no heater.
    Pictures for the general too.
    CCW filter complete 09172014.jpgCCW use oil filter + head.jpgCCW waterpump inlet to same size.jpgcoolant filter proper hookup return to pump.jpgcoolant filterwhat not to do.jpgphoto 2.jpgphoto 4.jpgphoto 5.jpgthis valve.jpg
    I was here, had a good time.

  12. The Following 2 Users Say Thank You to frank8003 For This Useful Post:

    Larry Weibert (11-08-2018), russojap (11-08-2018)

  13. #10
    4 Star General cattlerepairman's Avatar
    Join Date
    Jul 2007
    Location
    NORTH (Canada)
    Posts
    1,675
    Thanks
    703
    Thanked 983 Times in 498 Posts

    Default

    I drained the coolant, refilled with plain tap water, added CASCADE non sudsing detergent and ran the engine to operating temp. Then I drained again, unhooked the radiator hoses, put the garden hose into the upper radiator port on the block and ran the engine, water gushing out at the bottom until the water at the bottom came out clean.

    The radiator I took to a shop to have it boiled, pressure tested and fixed.

    Sent from my SM-G950W using Tapatalk
    Last edited by cattlerepairman; 11-09-2018 at 12:40.
    How much you paid for the truck is one thing. Upkeep and upgrading is an entirely different thing! 1974 M35A2C w/w "Queen Lola", rebuilt LDS-465-1A, "D" turbo, Waterloo Overdrive upgrade. Med towbar, 11.00R20 Goodyear G286, flipped hubs, remote brake fluid reservoir, bypassed FDC, LED taillights, LED headlights, LED turn signals, WESTACH EGT/boost gauge, AVM lockout hubs, LED convoy light, LED lollipop lights, HMMWV seat on air ride base, M211 dash passenger grab handle, hood lift kit, 24V solargizer/battery minder, ether start kit, flasher module mod, heavy duty dog bone ends, M35A3 aluminium fuel tank.

  14. The Following 2 Users Say Thank You to cattlerepairman For This Useful Post:

    Larry Weibert (11-08-2018), russojap (11-08-2018)

Page 1 of 2 1 2 LastLast

Similar Threads

  1. Flushing differential before refilling?
    By firefox in forum 5-ton and up
    Replies: 15
    Last Post: 06-08-2011, 15:22
  2. Flushing the brake system on an M-39
    By Robo McDuff in forum 5-ton and up
    Replies: 6
    Last Post: 05-10-2011, 09:29
  3. Flushing the transfercase
    By caladin in forum CUCV
    Replies: 11
    Last Post: 04-04-2011, 16:44
  4. Flushing Hydraulics
    By Unforgiven in forum Deuce Modification and Hot-Rodding
    Replies: 19
    Last Post: 01-22-2010, 01:29
  5. Flushing Brakes
    By papercu in forum Engine and Drivetrain
    Replies: 2
    Last Post: 10-25-2009, 15:25

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •