Getting coolant out the block

[Falcon_LS]

My Pajero/Montero needs a coolant flush, and the system is clean. I'm not too fond of using tap water from a garden hose in my cooling systems, even for flushing purposes, and was wondering if what I'm about to describe would be an acceptable method of getting the old coolant out.

1. Drain the radiator
2. Remove the lower radiator hose, let the coolant drain then reconnect
3. Remove the thermostat
4. Disconnect the upper radiator hose from the radiator
5. Start the engine and let it run for 4-5 seconds OR disconnect the fuel pump relay and crank the engine to move water out of the block

The coolant drain plug is a 14 mm plug under the driver's side exhaust manifold, just over the oil pan seal. It's a bit difficult to get to, and seeing it hasn't been touched in 13 years, I don't want to mess with it and cause myself problems. Thanks!

 

[ChiTDI]

I would think steps 1-4 would get enough out for an effective drain. Strongly agree on the nogo for the drain plug and saving yourself headaches.
#5 is really your call IMHO. Some risk, but you would know whether the reward is worth it.
How much stays in there, and how bad is it?

 

[ag_ghost]

I've done something like that on a V8 Mustang and have a similar dilemma in that the block plug is a major pain to access much less remove. In my case I back the car up on a couple of layers of 2x6 wood and the "downhill" helps a bit.
Good luck.
Kevin

 

[KB2008X]

Being concerned about tap water in your cooling systems is probably prudent, but if gallons of drinking water are available at a reasonable price it may be refined enough to be used with confidence. The same goes for distilled water. I have been using distilled water for years for flushing cooling systems, as we are on a well, with no problems.

If the same kind of antifreeze is going back in as was drained out, one or two flushes is what I'll do, with the thermostat removed and the heater on. This precludes a need to fool around with the block drains.

As for #5 on your list don't bother. The water pump won't have any coolant to pump out because you've already lowered the coolant level below the water pump.

Keith

 

[Rand]

if the system is clean why do you need to flush?

just drain and fill imo.

 

[440Magnum]

Step 5 is useless. Once the water level in the cooling system falls below the water pump impeller, the pump doesn't move any water. I've never seen a cooling system where the water pump was below the lowest parts of the block.

 

[HTSS_TR]

I had been using water from garden hose to flush my coolant via Preston T-flush in the LS400 many times. It has almost 300k miles and no coolant related problem (except a small crack on top of the expansion tank which is common for LS400-LS430 from 2000 to 2009)

 

[Falcon_LS]

Thanks for all the input.

If I go through steps 1-4, can I disconnect both hoses and blow compressed air from the thermostat housing to drain anything that may be left inside the block?

I've always used distilled water in my cooling systems, although it is a bit of a pain because they are only sold in 1 liter bottles. I end up filling 10 liter containers and using that, but end up with back pain afterwards because I normally go through at least 80 liters. Considering the system is clean, I thought I'd just get all the old coolant out, refill then burp.

 

[Garak]

Originally Posted By: Falcon_LS
I've always used distilled water in my cooling systems, although it is a bit of a pain because they are only sold in 1 liter bottles.


I wouldn't have an issue using tap water with or without a T-fitting flush, as long as you could give it another flush with distilled water. Another perfectly acceptable alternative to distilled water is RO water, and I bet you could find that in much larger jugs than the one litre jugs of distilled you're used to.

 

[Mr_Incredible]

When I was replacing a water pump on the LS1, I took the opportunity and changed over to green antifreeze from dexcool. I put the shopvac hose up to one side and a garden hose on the other and flushed as much dexcool as I could. I thought it worked pretty good.

Feeding distilled or deionized water into the block would have required an elaborate feed mechanism that wasn't worth it for me. I wasn't anal enought for that rigamarole.

 

[KB2008X]

Originally Posted By: Mr_Incredible
Feeding distilled or deionized water into the block would have required an elaborate feed mechanism that wasn't worth it for me. I wasn't anal enought for that rigamarole.


What!?? "elaborate feed mechansim" ? What are you talking about ?

You just pour it in the radiator - the same place the antifreeze goes. What is so hard about that ?

Keith

 

[mechtech2]

Drain what you can. Measure what is drained compared to the total dry fill amount. You can then figure out exactly how much AF to use, and at what exact percentage.
Use distilled water to refill.
Start her up and get it hot.
Do this a number of times.

Do you need a real flush? Get Prestone flush and follow their direction. Then, use mine.

 

[KB2008X]

Falcon - No, compressed air isn't going to get below the leftover coolant in the block and lift it out. You'll accomplish nothing with that.

I've heard of some people having success with the shop-vac method of vacuuming out the engine block, as Mr.Incredible mentions. You may want to consider that if you have a shop-vac.

If you're confident the cooling system is clean then just drain what's in there as best you can and refill. It's not a big deal.

If you want to get what is left in the block out of there, the easiest, hassle-free way to do that is like this:
1) Drain the cooling system, then refill with your choice of water.
2) Run the engine, with or without the thermostat (I like to pull the stat). You may want to turn the heater on, depending upon how your system is set up, to flush the heater core. If you leave the thermostat in be sure that the stat opens, then run it a little while longer. Better yet, just drive it around for 15-20 minutes.
3) Drain the system again, reinstall the stat, if it was removed, and refill with the appropriate amounts of coolant/antifreeze and your choice of water.
4) Repeat the drain and flush if needed, in your case once should be enough.
5) A gallon and a half of water, 6 liters, should be all you need for the flush. The water left in the block when you're done with this quick and easy flush can be counted towards the water that you'll add to the coolant to arrive at a 50/50 mix.

This method removes as much of the coolant, that is left in the block and heater core after draining, as possible. And there is no need to futz around with removing the block drain plugs, shop-vacs, compressed air, or anything else.

Why anyone would want to do it any other way is beyond me. It is a very simple, time-honored and cheap method of changing the coolant.

Keith

 

[mechtech2]

But why get it dry? there is no point to getting it totally dry.
As long as the system is clean, and clean water is in there, we should be happy.
Just remember to note the amount drained compared to the dry system fill amount to calculate your new mixture of AF.

 

[Mr_Incredible]

"What!?? "elaborate feed mechansim" ? What are you talking about ?"

At the time of my changeover I had the water pump off. The radiator was empty and unhooked.

I was talking about getting any leftover dexcool out of the block. I would have had to fix up a funnel and a hose and drained it into one side while sucking it out the other. Simple garden hose work was sufficient for me.

 

[Eddie]

How to make major project out of something simple. )

 

[stang5]

how about lifting the back end of the car? like reverse it up a ramp.

 

[Tegger]

What an unbelievably silly and complicated thread! And all because the OP is too scared to do the job properly by simply removing the 14mm block drain, which will almost certainly come out without any problems at all.

 

[Falcon_LS]

Originally Posted By: Tegger
What an unbelievably silly and complicated thread! And all because the OP is too scared to do the job properly by simply removing the 14mm block drain, which will almost certainly come out without any problems at all.


With all due respect, I could care less. Yes, the bolt will come off after going through a can of CRC Freeze Off and a bit of elbow grease, but I simply don't want to mess with it. Not when it's 120 degrees outside anyway.

I've been in this situation before with other cars with well maintained cooling systems. It's okay to take risks, but when the head breaks off and you go through h3ll and high water, only for it to leak coolant afterwards, it's simply not worth the hassle.

It's also hard to find shops around here to help you out professionally when poop hits the fan. This isn't Europe or North America, I'm afraid.