what comes first

[stamar]

flushing the cooling system

or putting on new hoses?


Do you put prestone flush in the system with the old hoses on first, or are you just cleaning out old hoses?


is flush bad for new hoses?

which firsT?

[paperplane94]

When I flushed mine I drained, R&R hoses, flushed rad/block with garden hose water, then I used the prestone flush(the one that you leave in for 5 hrs. driving) with tap water. Then I flushed with two gallons of distilled water from vons, then i refilled with the 50/50 zerex go5 coolant and distilled water.

I think I wiped out the local vons of distilled water for a few days:)

Mind you, my coolant hadn't been changed for 6 years and tap water was used so it was rust brown and opaque. After the flush, crystal clear and works great. I kept the old hoses in the trunk just in case I have a failure too.

[stamar]

ok well if Im doing that, then im there. so you say, flush out junk into brand new hoses?

Is that right?

I honestly have no idea anyone else vote?


well these hoses have already broken in 2 spots and are brown on the inside.... but i will keep em around like you for emergency.

so you also flushed out distilled water? I dont know about that particular step. I think tap water is fine for that step.

[jlevie]

If the flush is done properly it doesn't if change the hoses first or after. The critical parts of a flush are using a major brand flush compound and then washing out the engine. The way I do it is to:

1) Get the front of the car 1-2' in the air on jack-stands.

2) Drain the coolant, remove the thermostat, and set the heater controls for
full hot. O-ring sealed thermostats require you to make up a temporary
gasket, which can be made out of pasteboard.

3) Add flush compound and fill with plain water. Then run the engine at normal
temperature as specified by the flush manufacturer (usually about 15
minutes at operating temperature). In cooler weather it may be necessary to
block off some of the air into the radiator to decrease the warmup time.

4) Allow the engine to cool until you can place your hand on the cylinder head
w/o discomfort. Drain the system and refill with plain water.

5) Run the engine for 10-15 minutes or until temp is close to normal.

6) Repeat (4) and (5) until the water drained from the system is clear and
free of debris.

7) Fill with coolant. It is best to dilute anitfreeze with distilled water.
Tap water contains disolved oxygen and may contain minerals. Either of
which will reduce the lifetime of the coolant.

Notes:

You don't absolutely need to remove the thermostat, but doing so will allow
continuous flow through the radiator and will also make draining & filling
faster and easier.

Always allow the engine to cool to the point that you can hold your hand on
the cylinder head without discomfort. That will prevent scalds from hot
coolant and prevent thermally shocking the head when you dump the coolant.

Filling the system with hot water makes the process go faster and keeps from
having to run the engine a lot in a cold condition (rich mixture).

[paperplane94]

When I flushed mine I drained, R&R hoses, flushed rad/block with garden hose water, then I used the prestone flush(the one that you leave in for 5 hrs. driving) with tap water. Then I flushed with two gallons of distilled water from vons, then i refilled with the 50/50 zerex go5 coolant and distilled water.

I think I wiped out the local vons of distilled water for a few days:)

Mind you, my coolant hadn't been changed for 6 years and tap water was used so it was rust brown and opaque. After the flush, crystal clear and works great. I kept the old hoses in the trunk just in case I have a failure too.

I guess you could fit the new hoses AFTER you've done the prestone flush.
I don't think it would make a huge difference though, as long as the water running out of the rad/block is clean then you know your ok.


^Great write up JLevie! I wish I had removed my thermostat when I did mine. I was having to bleed, then drain, then bleed, then drain. Removing the thermostat for the first few steps would have been much nicer.

[stamar]

Well ive got 3 hoses, and one is on its way. according to what you just said im going to put 3 on

use the prestone flush.

then put the top hose on and put in some new coolant.

[dnguyen1963]

Drill a small hole (3 mm) on the top of the t-stat wall. This will make bleeding the system much easier and faster.

[stamar]

all internet write ups say to change the hoses before doing a flush.

They do not describe why.

My theory is: looking at these hoses the inside is covered with brown junk. the same stuff is inside the block.

Why clean that stuff off the hose you are about to throw away?

just throw it away. That much less junk to remove.

It makes sense to me. So first comes hoses then comes coolant flush.

[BergerNJ]

so I have either a bad head or bad head gasket thats leaking oil into my coolant......Im either going to repair my head or get a rebuilt unit, when I have the head off....Im going to replace all of the rubber when I'm in there.

..So I guess when I have the rad off I can flush it with a hose? How would I really know if my rad needs replacing, if it doesn't leak and have any noticeable visible damage it should be ok right?

then Ill put everything back on-new rubber and all, and run a full flush as above posted by jlevie to make sure my engine is cleared?

[stamar]

ya oil in your coolant makes your hoses die fast.

So in general stop the oil leak before you invest in the hoses.

So you are wondering what sort of flush you should use when you have oil in your cooling system?

Well other than prestone or some sort of radiator flush, I have heard of people using dawn dishwashing liquid.

I dont have any oil in my system but if I did I would try it out.

I do not actually know what sort of chemical mixture is made by soap and coolant flush but id make sure the soap was completely out before the next step.

[TurboJake]

It makes no difference in when you do the flush. Before or after the hose change.

Just keep in mind, people say to do it after changing the hoses because:
1: the flush can dislodge stuff in there on the old weak hoses, and possibly cause a leak/depressurization.
2: with the old hoses, there's more gunk, which can clog the radiator and heater core easier.
3. Excessive cooling system smegma causes undue stress onto the water pump.

Now, mind you this is for a car that has never had it done, or the cooling system wasn't maintained at all. The likelihood of all of these is indirectly proportional to the amount of fucks that were given to the cooling system before you owned it.

[stamar]

bergerj

prestone and peak radiator flush both say they remove oil.

Whatever other brands exist do too Im sure.

Im not sure what you have around that helps to clean your radiator while your car is in peices. But the coolant flush uses the cars own pressure to help clean it. Id wait until you have the water pump hooked back up before cleaning it personally.

[stamar]

quickie.

The worst hose is the top hose. Terrible terrible design in the e30. I actually bought a gates top hose and its design is different a touch for this application than oem. just less spin by the radiator top. 12 free shipping at amazon.

My oem had a patch on it put on by some previous owner in the spot where it will fail, the twist before the radiator
The other spot it will fail is in the connection to the block, that is the hottest peice of metal that is the first spot to spring a leak.

[edit after i wrote this, I learned a PO had put the top hose on backwards. then when it failed, they put a patch on it. You can disregard the stupid design comment. I dont even know how you can be that retarded. It is possible that what happened was the hose failed, he patched it and then turned it around to get the patch away from the heat, which if that is true is sort of smart. Then sold it )


On the opposite end, the lower radiator tube goes next. this is because its connected to a vibrating peice, the engine, to a stationary or vibrating a different way. Basically its a suspension bridge.

Next the funky block to thermo. The bottom of it is hot, it is doesnt take abuse though.

The last one is tube to thermo housing. It doesnt move or get hot... it shouldnt logically be a hose.


however... the worst hose to fail is the lower radiator hose ( happened to me) as that is the biggest fastest catasprophe. The most common one by far is the upper one lettin out a little high pressure leak you cant understand.

[stamar]

Hey earlier in this threa I advertised something called k seal

well after using it Id just like to give it a negative review.

It is just like much cheaper stuff. such as bars leak. copper weld etc.

what its working ingredient is in part is cellulose. Or fiber from the pepper tree. works into the crack when cold and then inflames when hot. perhaps sealing a small hole temporarily ( as the coolant will eventually dissolve the cellulose.

oldest crap in the book. Not even on the level of blue devil or whatever just old school

raw egg will work too. thatll hold for like um.... a day.