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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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355 Posts
Discussion Starter #1
Hey Guys,

so my heater core is clogged once again...

Little bit of history:
- From all that slimy stuff that came out during the first cooland flush I did i guess the car never ever had a coolant flush before I got it
- Heat was only coming from the passenger side -> lower portion of the heater core remained cold.
- forums suggested a clogged core.

I've flushed the cooland system three times over a couple of weeks to get rid of the old stuff, heat distribution improved a lot but after a few weeks the core was clogged again. I've then tried a cleaning solvant to find out that the core decided to leak :D
So i've replaced the core in April 2014 - heat was fine immediately. Unfortunately over the last few weeks it slowly degraded again, passenger side hot, driver's side cold. Lower portion of the core was cold again. Then it even started clogging the upper portion of the core, so the passenger's side was only luke-warm.

I've replaced the core in 2014 with the ACDelco 15-60064 GM Original Equipment Heater Core.
From what I read on the web those cores tend to clogg up fairly often but I am unable to find a non-AC-Delco replacement part that fits.

What do you guys think? Why does it keep on clogging or what can be done here? :)

Thanks!
 

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Super Moderator
2010 DTS
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It sounds like the previous owner was diligent or maybe even over diligent in following GM's advice on using sealant tabs. You might try having it power flushed.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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355 Posts
Discussion Starter #3
Ah I see :)

Power flushing the core or the entire system? I've already given hell to the system itself with the help of a pressure washer multiple times in multiple directions and hoses - or do you mean something else?

The last time the core clogged, flushing the core by itself got rid of some brownish stuff but since it did not help much i figured there's not a decent way to unclogg an already clogged core :(

BTW: is there a sort of in-line filter to counteract this problem? If I could insert such a filter at the t-portion of the hoses where it would be easily accessible for cleaning i would be so happy... :D
 

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1993 deville
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92 Posts
u must have a really good clog if u already used the pressure washer...no filters for the rad that i know of...dont think the water pump is even strong enough
 

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98 DeVille, 97 DeVille d'Elegance
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7,345 Posts
No filters. They would reduce flow so quickly wouldn't be fesible unless a large screw on type lik3 semi use.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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355 Posts
Discussion Starter #7
No filters. They would reduce flow so quickly wouldn't be fesible unless a large screw on type lik3 semi use.
My fear as well. Check out this filter tough:
http://www.ve-labs.net/products/coolant-filter-and-inspection-system

That'd be super cool at the t-junction behind the motor....

I'd do the entire system with something like this

or this

or take it to a radiator shop. They have the tools.
Nice! Gotta ask my mechanic if he has something like this. I am hesitant to give a cleaning solvant another go. I don't want to get leaks. Or is there a product that can be recommended? :)
 

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70 Deville 77 Fleet 78 Seville 92 Deville 03 Deville
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3,310 Posts
Can't you just back-flush it with one of those Prestone coolant flush kits? Since the core was new last year I would think it would clear out fairly easy.
 

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1992 DeVille, 2013 ATS 3.6
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2,366 Posts
Is a symptom of a clogged core hearing burbling coming from it? (I know this would be a symptom of air in the system)
 

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2010 DTS
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Can't you just back-flush it with one of those Prestone coolant flush kits? Since the core was new last year I would think it would clear out fairly easy.
He could, but based on what he said in post #1, I am assuming that the rest of the cooling system is loaded with sealant tab residue and flowing into the core. That's why I suggested power flushing the entire system.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
Does the car have any other cooling problems? It's not that hard to get the sealant tab residue out so maybe they were putting something else in there.

If you are going to try flushing the system disconnect the heater hoses at the engine completely to prevent anything else from being forced thru the heater core.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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355 Posts
Discussion Starter #13
Hm no, I don't see any other problems related to heating/cooling. Thermostat opens fine, Enginge operates within normal temperature parameters.
I've replaced the coolant three times now - If there's still something in there, its really stuck. I don't know what the previous owner did with the car. When i first flushed the system the coolant had no anti-freeze in it and was looking like root beer.

Mile-Wise the new Heater Core clogged within 1000 miles of having it in the car over a period of 1 year (I don't drive that much with the caddy)

This pic is from the SECOND flush...



I am very heasitant to take the car to a radiator shop. We've only got one specialized in this kinda work and this guy ripped me off already with a 500 USD bill for an A/C system flush and improper (aka leaking) installment of the A/C lines. Also such a job would easily cost me 300-400$$$.

How are those pressure nozzles called? Perhaps I can get some from amazon.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
If that's all from sealant tabs someone put a shit load in there. Can you even readily get the tabs over there or is there some other product that you guys get? If whatever that stuff is is still in the system it will definately clog things up again.

That looks very similar to what comes out of a cast iron engine block that someone has been running straight water in, neglected and sitting for years.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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Discussion Starter #15 (Edited)
Phew, no Idea if those tabs are available here. When I got the car it was loosing water fast due to a faulty radiator cap. Perhaps the previous owner dumped some sealant stuff in there to "fix" this...
Is the 4.9l V8 made out of iron or aluminum? My mechanic over here tells me that i should not worry about using tapwater instead of distilled water as the added coolant prevents the forming of deposits from water. So after we've flushed the whole system we put a 50:50 tap water / coolant mixture into the system. My mechanic is specialized in the German Volkswagen, so there may be some differences in opinion... ;-)

I'll try flushing the core itself next week, maybe add some solvant to just the core and let it sit for a few hours. Too bad that there are no inline filters available and the poor heater core has to do that... :D

Edit: hmm how about i put something like this within the hoses for a few minutes to get rid of the bigger stuff?

http://www.ebay.de/itm/Abfluss-Sieb-Bad-Haarsieb-aus-Edelstahl-Schmutzfanger-Stopper-Waschbecken-Dusche-/270960335726?pt=LH_DefaultDomain_77&var=&hash=item3f167e9b6e

Some Jaguar Fans tried that... http://www.jag-lovers.org/xj-s/book/CoolantFilters.html
 

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2010 DTS
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The color of that coolant is indicative of sealant tabs.

Distilled water simply does not have the normal tap water minerals, (calcium, lime, iron etc.). Purists like distilled, but tap water is not going to do any harm.

DO NOT put any cooling system filters in it. :tisk: It will come back to bite you in the ass.
 

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'93 Sixty Special 4.9l V8, '01 Sebring Convertible, '13 300C
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Discussion Starter #17
The color of that coolant is indicative of sealant tabs.

Distilled water simply does not have the normal tap water minerals, (calcium, lime, iron etc.). Purists like distilled, but tap water is not going to do any harm.

DO NOT put any cooling system filters in it. :tisk: It will come back to bite you in the ass.
Aye Sir! :)

btw: this is how the radiator cap looked like when i got the car...


 

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Really hard to tell from those pics if it is sealant tab residue or rust, but I'd lean towards residue. Sealant tab residue will was off much easier than rust.
 

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1991 Cadillac Brougham D'Elegance 5.7 Litre, 1994 DeVille
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6,796 Posts
I think it's a mixture of both. And if that was once green coolant it just shows the neglect.
 

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1995 SEDAN DEVILLE-4.9 & 1978 SEDAN DEVILLE-425
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1,673 Posts
Mr

Had my problems with too much GM sealant tab stuff in my heater core recently in my`95 Deville.
Took it in to a shop for a heater core/engine flush and been blowing great hot air ever since.
Then with all the sealant stuff gone it opened up leaks in the radiator that had been sealed,so I had a new radiator put in.
Never again with the sealant stuff.
 
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