removing radiator stop leak
 

A friend put in stop leak and now the heater core is blocked. Unfortunately
it is much harder to replace than radiator or thermostat (which seem to be
okay anyway). He put some detergent in the coolant and reversed the hoses,
which achieved nothing. Look through other forums, I see various ideas:
1) put vinegar or tartaric acid into radiator, warm up engine then rev it to
4000 RPM. Then quickly flush system with water and refill with correct coolant.
2) disconnect heater hoses, and pump gasoline into it. Then flush heater with
water.

I gather that trying to blow it out with compressed air is bad, as this may
dry out the stop leak, making it worse.

Has anybody succeeded with clearing a clogged heater?

removing radiator stop leak
 

removing radiator stop leak
 

On 13/6/20 12:06 pm, wrote:
> A friend put in stop leak and now the heater core is blocked. Unfortunately
> it is much harder to replace than radiator or thermostat (which seem to be
> okay anyway). He put some detergent in the coolant and reversed the hoses,
> which achieved nothing. Look through other forums, I see various ideas:
> 1) put vinegar or tartaric acid into radiator, warm up engine then rev it to
> 4000 RPM. Then quickly flush system with water and refill with correct coolant.
> 2) disconnect heater hoses, and pump gasoline into it. Then flush heater with
> water.

That's pretty much a standard event with some forms of stop leak. It is
also why I *fix* the problem properly by repairing the leak at its
source in the time honoured manner. The problem is that the flow through
the heater core slows allowing the lumpy bits to sediment out.
>
> I gather that trying to blow it out with compressed air is bad, as this may
> dry out the stop leak, making it worse.

Any form of cleaning, including flushing, will likely bring about the
return of the leak that you originally tried to fix. It may also
discover *more leaks* for you.
>
> Has anybody succeeded with clearing a clogged heater?
>
Remove, properly flush, refit. That stuff sticks like baby**** to a blanket.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

removing radiator stop leak
 

> wrote:
>A friend put in stop leak and now the heater core is blocked. Unfortunately
>it is much harder to replace than radiator or thermostat (which seem to be
>okay anyway). He put some detergent in the coolant and reversed the hoses,
>which achieved nothing.

It does that. Replace the heater core. Don't just remove it and try to clean
it either. Likely there is enough stop leak in the radiator that if it comes
out, it will clog the heater core up again, so it may be worth replacing
the radiator pre-emptively as well. At the very least try to do a reverse
flush on the radiator.

The first question: where was the leak that he was trying to stop? If it
was in the radiator, the radiator has to go anyway. Worry first about
fixing that leak because fixing it may free up more stop leak to clog the
heater up.

Also.... make sure it is the heater that is clogged and not the valve.
The valve may be comparatively easy to replace, rebuild or clean. Either
way, it's something to clean before touching the heater core.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

removing radiator stop leak
 

On 14/6/20 12:33 am, Scott Dorsey wrote:
> > wrote:
>> A friend put in stop leak and now the heater core is blocked. Unfortunately
>> it is much harder to replace than radiator or thermostat (which seem to be
>> okay anyway). He put some detergent in the coolant and reversed the hoses,
>> which achieved nothing.
>
> It does that. Replace the heater core. Don't just remove it and try to clean
> it either. Likely there is enough stop leak in the radiator that if it comes
> out, it will clog the heater core up again, so it may be worth replacing
> the radiator pre-emptively as well. At the very least try to do a reverse
> flush on the radiator.

Any radiator that is 10+ years old should be replaced pre-emptively
because the plastic top and bottom tanks, which get brittle with age and
heat cycling, are likely to crack and develop a massive leak.
>
> The first question: where was the leak that he was trying to stop? If it
> was in the radiator, the radiator has to go anyway. Worry first about
> fixing that leak because fixing it may free up more stop leak to clog the
> heater up.
>
> Also.... make sure it is the heater that is clogged and not the valve.
> The valve may be comparatively easy to replace, rebuild or clean. Either
> way, it's something to clean before touching the heater core.
> --scott
>
Most modern cars I've seen no longer have a heater valve as such. They
were always a point of failure - sticking, blocking, leaking, etc. The
trend now is to run hot water through the heater core all the time and
use *air flow control* to regulate the car's internal temperature. For
this purpose they use a *blend door/flap* in the heater/AC to achieve a
much more rapid temperature change - necessary with climate control.

--

Xeno


Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)

removing radiator stop leak
 

On Saturday, June 13, 2020 at 12:07:32 PM UTC+8, Steve W. wrote:
>
> About the only way I have gotten any success with a core clogged with
> stop leak was to use a flush gun and blast it in reverse, even then it
> wasn't a big success but the core did provide some heat.
> The one I have uses shop air and water to generate pulses of pressurized
> water to break up crud and flush it out. It's a twin to the OTC 6043
> but I've had it for a long time..
>

He took it to a radiator workshop. They flushed it with their rig.
Now it is lukewarm, so half the tubes are still probably blocked.

removing radiator stop leak