Heater core failure after 3 months

[dlundblad]

It's been in service since July in my Blazer. It's been gurgling at startup for a few weeks now and yesterday I noticed coolant drops on the passenger side floor mat.. Interestingly enough, there is no coolant smell or steam from the defrost, which originally lead me to believe it had a bubble in the system somehow. I did a lot of driving this weekend with a loaded trailer and OD off so perhaps the higher RPM's caused the issue to surface?

I ended up using the AC Delco Professional part from Rock Auto with a lifetime warranty. I would have entertained OE, but from what I saw it had a 3 week back order. Aside from that, there's no other name brand available besides what the parts stores sell. Hopefully mine was just a dud and this isn't a preview to coming attractions..

 

[Garak]

It happens, but hopefully that was a one off. In so many vehicles, that's such a pain in the butt job.

 

[Black_Thunder]

indeed it seems like heater cores are just duds sometimes.


5 years or so ago I had to replace a heater core on my brother's f150 that had just been put in by a shop about 6 to 8 months prior when he was living in alaska.

don't know what brand it was but i replaced it with whatever brand Advance auto had at the time and no issues since then.

 

[Trav]

If its a big job go OE and eat this one, aftermarket one are garbage. If its like an old Ford with a few sheet metal screws under the hood and pop the hoses and 5 min later its out them fine use them. Delco pro is one step up from white box and nowhere near the quality in materials and finish to Delco OE.
If the vehicle doesn't use a Ranco style bypass water valve but an air door consider installing one, they come in many variations, manual (basically a summer/winter) lever, cable and electric with or without a thermostat module.

That way in hot weather you can shut the flow of water through the core, this only prevents erosion of the core (which GM in particular had some issues with) but greatly improves A/C performance especially on older vehicles where the seals are getting tired.
This is an easy to install item and not very expensive.

Edit: Many cores are damaged installing them, be careful with the pipes and lube the inside of the hoses with WD40 (there is nothing better for rubber to metal like hoses and o rings) it lets you get the rubber on the metal easily and dries completely without damaging the rubber.

 

[demarpaint]

In the case of my Wrangler if the heater core goes it is a royal PITA job to do. I would do my homework and source out the best possible heater core there is at the time for it and use that. Cost of the part would not be a factor.

 

[Chris142]

A loose clamp can cause it to drip inside.

 

[Jimzz]

Originally Posted by Chris142
A loose clamp can cause it to drip inside.


Yea check the hose connections before taking anything apart. I have seen that be an issue with many, esp some newer ones that have o-rings inside them.

 

[Delta]

Originally Posted by dlundblad
It's been in service since July in my Blazer. It's been gurgling at startup for a few weeks now and yesterday I noticed coolant drops on the passenger side floor mat.. Interestingly enough, there is no coolant smell or steam from the defrost, which originally lead me to believe it had a bubble in the system somehow. I did a lot of driving this weekend with a loaded trailer and OD off so perhaps the higher RPM's caused the issue to surface?


Oh don't say that, lol. Mine has been doing that for over a month now, sounds like a rush of water. Its been about 10 months since I did mine, but I used a core from Carquest that was made in China...

I drive about 10 minutes heavy throttle/high rpm's going up the mountain, so maybe we're having the same issue.

 

[GON]

Very sorry that happened. I replaced a 1998 S10 heater core a few years back, not only is it very time consuming, but you have to twist your body in many different ways to get at things- it is a painful job for a different reason. Good luck with the follow on repair.

 

[maxdustington]

That sucks. Perfect timing, too.

Heater cores and anything that involves dash removal are my #1 fear. My car blows some air with the AC and heat off but taking my entire dash apart is not worth it. I was thinking about pre-emptively flushing the heater core but I am scared about breaking it in the process.

 

[jfin2002]

About to do this job on a 2002 dodge ram 1500. Have to remove the entire dash, so I will be be replacing the heater core, evaporator core, and all the actuator doors. NOT looking forward to this !

 

[Trav]

If the vehicle doesn't have one of these already or is missing put one in. This is an OE GM part used in many models and service TSB for others.
It slows down the coolant flow slightly and stops the turbulence which causes the erosion commonly found in vehicles with blend doors only.
This one is 5/8 and will fit many vehicles.

https://www.amazon.com/ACDelco-15-5...mp;psc=1&refRID=SF69SQTE77RJA4BHZKEE

There are other types to fit almost anything just google heater core restrictor.
OP as others have said check the clamps, I assume you did this but you never know. I figure if someone can do a job like this on their own they know enough to trouble shoot it before tearing it out again.

 

[HangFire]

Originally Posted by Trav
Edit: Many cores are damaged installing them, be careful with the pipes and lube the inside of the hoses with WD40 (there is nothing better for rubber to metal like hoses and o rings) it lets you get the rubber on the metal easily and dries completely without damaging the rubber.

Trav,
WD-40? Do you not recommend Hylomar AF for heater cores, like you have for radiators? I guess the difference might be metal barbs instead of plastic?

BTW, I have to say "thanks." I did my 05 Pilot radiator recently, and followed your advice (probably given a couple of years ago) to use Hylomar AF. I also used my AirLift for the first time to do the test and fill. What a joy to use!

Anyway my only real contribution to this thread is to recommend the UView AirLift to do a vacuum check on the whole coolant system, and then the ridiculously easy coolant fill. You get peace of mind AND a quick job, well done.

 

[Trav]

For metal heater core pipes I use WD40, Hylomar on plastic because of their leak prone nature with wide temp ranges eg winter temps. Hylomar would work as well but it would be a waste of product in this application and its not cheap stuff.
On aluminum thermostat housings that are probably pitted on an old car Hylomar for sure. On metal heater core pipes and fuel hoses you are looking for easy of installation (the less stress the better) not really additional sealing.

 

[HangFire]

Thanks for the clarification, Trav.

 

[dlundblad]

Well, it looks like it was the hose clamps at the firewall. This is the first day of use after tightening them, but it looks promising. Interestingly enough, they were already somewhat ballooned at the clamps too.

 

[Trav]

What kind of clamps are you using. Please don't say worm clamps.

 

[Delta]

Originally Posted by Trav
What kind of clamps are you using. Please don't say worm clamps.


I was wondering the same thing, I've never had luck with those (worm clamps). People hate them, but I've always had luck with the OEM constant pressure clamps. The pipe ballooning at the clamps makes me think they might have been over-tightened and failed. I see this alot in an industrial setting.

 

[Trav]

Yes those and exhaust U clamps should be banned, garbage both of them.

 

[The motor guy]

It's why I kept my oem heater core in. I always keep up on the coolant changes, so we will see.