Coolant flush

[Knucklehead]

I did search - promise and sure this has been covered before but I am trying to figure out the most effective way of flushing out old coolant in the rad/engine/matrix's etc..

Going to be dropping the old coolant next week to fix up my No1 bypass pipe and thought should give the system a good blast with the garden hose.

As I still have my rear heater in use I'm wondering once drained through the rad/engine block plugs how could I give the 2 heater matrix a bit of a flush as well?

Wondering what hoses would be best to hit with the hose to try and flush out as much of the system as possible? Don't really want to start adding cleaning chemicals and the likes in there.

Any advice appreciated or any links to existing procedures.

Cheers,
Dave.

 

[yogi]

Why don't you want to use cleaning chemicals?

 

[Knucklehead]

had read on IH8MUD warning people off sticking chemicals in these engines. Never really said why, maybe causes more harm than good on engines of this age.
Anyhow, maybe I will just need to a rad/engine flush with a hose and not worry about clearing out the heating matrix's.

 

[Ale]

I changed my coolant about 4 months ago when I swapped out my water pump. The coolant was rusty water before, and I thought I'd try a coolant flush. Though the product I used, think it was Wynns coolant flush, seemed to be little more than some soapy substance. Certainly filled my coolant system with bubbles - think it was harder to flush out the bubbles than rusty water...

Only problem I have is my radiator's now sprung a leak, and I need to do the same thing again, as the coolant has gone a little rusty. Presumably as its leaking a little air, or there was residual rust in the system or maybe the coolant rust inhibitors were a little too weak to be effective!

This time round I had bought a two part flush product from Holt, and was going to give that a go, but with old radiator fitted, as not sure I want my radiator full of chemicals or soap.

Would also be interested to hear what anyone else has to say!

 

[Knucklehead]

what concerns me about adding chemicals into the system is they will get around the rad and engine block but I would have thought they would also make it into the front/rear heater matrix's.
They could be flushed out of the block/rad easy enough but wouldn't be confident it could be flushed out from the rest of the system.

Getting a bit away fro my original question. How do you flush out the engine/rad and the heater matrix's?
Is it possible to direct a garden hose in the coolant hoses to flush the whole system. Thinking the thermostat would stop the flow as wouldn't be open until reached operating temp.

Might be more bother than its worth to try a full flush.

 

[Towpack]

For a flush to be 100% effective you really need to remove the 'stat and replace with a new one while you're at it. This makes flushing with a garden hose easy including both heater matrix'. Unless I had a blockage or sludge problem I wouldn't use any cleaning additives. I had a blockage problem (heater not blowing hot) a few years back on a newly acquired V6 Sierra. Used a rad flush compound and a large amount of brown gelatinous sh*te came out of the matrix and block. The heater worked fine after that but it turned out one of the heads was cracked and the crap that came out in the flush was some sort of leak stopping compound. Went back to the dealer and he coughed up for a new head and gaskets etc.

 

[Knucklehead]

like the idea of replacing the stat while in there.
I've no intention of putting chemicals in as have no coolant issues. Would only end in tears.

I had planned on pulling these two hoses to flush out the rear system.
Is this the best place to try and flush the rear matrix?

 

[frank rabbets]

Why not just replace with clear water, run for a few days, drain down and replace with antifreeze/ethylene glycol. If your heaters work perhaps there is no point in flushing them.

Not sure about the 80 heater matrixes but modern ones are amazingly fine tubed and easily block up with their own corrosion. If you apply any pressure trying to flush they fall apart. Had this on my Audi and it blew clouds of steam out of the heater vents which filled the whole car up so you had to drive with the windows open and stop regularly to wipe the inside of the screen.

 

[Knucklehead]

Cheers Frank. Starting to think I could do more harm than good with the flushing idea. Will try your idea, seems like a good one.

 

[clivehorridge]

Why not just replace with clear water, run for a few days, drain down and replace with antifreeze/ethylene glycol. If your heaters work perhaps there is no point in flushing them.

Not sure about the 80 heater matrixes but modern ones are amazingly fine tubed and easily block up with their own corrosion. If you apply any pressure trying to flush they fall apart. Had this on my Audi and it blew clouds of steam out of the heater vents which filled the whole car up so you had to drive with the windows open and stop regularly to wipe the inside of the screen.

I'm with Frank on this one. Clean water but not for too many miles then replace with propriety brand antifreeze. It has it's own anti clog chemicals and lubes the seals.

 

[MuckyPup]

I used to swap the matrix pipes over, refill with plain water and repeat a few days later. Seemed to work well until I actually took one out and looked. Now I use citric acid. If it causes a leak then its done you a favour.