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General >> Problems >> heater blows cold air only??
(Message started by: lucydog on Feb 2nd, 2008, 5:16pm)

Title: heater blows cold air only??
Post by lucydog on Feb 2nd, 2008, 5:16pm
hi, today my scorpio would not blow any heat from the heater it only blows cold air? (not to good on a cold day like today).  the coolant level is the same and coolant is getting hot as normal?.. any ideas?? :-/

Title: Re: heater blows cold air only??
Post by Scorpio_Mike on Feb 2nd, 2008, 6:03pm
Sounds like the 'ol blocked heater matrix' problem - try flushing it through. This may give you a bit of warmth but usually the only long term fix is to replace the matrix...or trade the car in like I did when this happened on my '93 Granada Scorpio.
There are quite a few articles / threads on this site all about heater matrix problems and replacement.

Title: Re: heater blows cold air only??
Post by the_machine on Feb 2nd, 2008, 6:20pm
the valve actuator could have stuck or as Mike says the matrix is blocked. I was successfull in flushing mine and that was 3 months ago. Its still working. I used caustic soda.

Title: Re: heater blows cold air only??
Post by Snoopy on Feb 2nd, 2008, 7:01pm
Before you do any of that .. a couple of questions ... Do you have Climate control or just A/C

If you have CC then do a reset if you had hot air before then that should fix it...

If not then most likely scenario is a blocked matrix.


Title: Re: heater blows cold air only??
Post by jonnycab on Feb 3rd, 2008, 3:07am
Check both the matrix inlet & outlet matrix pipes. They should be the same heat & too hot to hold when engine has warmed up. If the inlet pipe is hot, but the outlet pipe is cold, then you have a blocked or restricted heater matrix  :)

The matrix can be flushed with a hose, but in my experience this was only a temporary fix.....I replaced the matrix in the end  :)

But I've recently read that phosphoric acid may be the solution, as it breaks down hard water deposits (limescale).

Where can you buy phosphoric acid ?.......at any shop, in a can of Coke/Pepsi.

Cola drinks contain phosphoric acid.......god knows what it does to your guts  ::)

So why not try disconnecting the matrix hoses from the manifold & the engine, pour coke into the inlet hose until the matrix is full & it's coming out of the outlet hose, then plug both hoses & leave it over night  ;)

I've never tried this method of un-blocking a heater matrix, but if someone would like to try it & then post the results, then it would be interesting to see what happened  ;D

Title: Re: heater blows cold air only??
Post by ren on Feb 4th, 2008, 11:43pm
i had my matrix changed last week and the garage
gave me my old one back,on looking at it i think the
reason backflushing does not work is because the
pipe is not continuouse as say a heating element
were you have a start and finish,
there are 7 ubend pipes in the matrix and they
connect to the inlet and outlet as individual connections
there are 7 holes along the inlet and 7 holes along
the outlet so pressure of water will clear 1 maybe 2
but not the 7 pipes need something that can be
directed into each hole down the inlet tube to clear
each pipe 1 by 1  

Title: Re: heater blows cold air only??
Post by harry.m1byt on Feb 10th, 2008, 6:45pm

on 02/04/08 at 23:43:31, ren wrote:
there are 7 ubend pipes in the matrix and they
connect to the inlet and outlet as individual connections
there are 7 holes along the inlet and 7 holes along
the outlet so pressure of water will clear 1 maybe 2
but not the 7 pipes need something that can be
directed into each hole down the inlet tube to clear
each pipe 1 by 1  


That has been said before - that there is basically a sort of manifold at each end. My guess would be that the tubes through which the coolant passes through with least velocity, are the ones which block up first. Once the blockages start, complete pipe blockage is not too far away.

Just a thought on this....

I wonder if the RTL cleaning fluid, as used by commercial a/c engineers for cleaning the alloy cooling fins of a/c units might also work to clean out a matrix?





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