Hi Folks, have a 99 4.6L Expedition with 147k that has started loosing coolant about a gallon in the last 3 weeks (smells in the interior but no noticeable fluid inside). Puddling is noticed on the ground near the right hand Catalytic converter - Pressure testing by a local shop indicates a heater core leak and a $950 bill required (due to having to rip out most of the dash etc. $600 labor). In doing some reading I've noticed several different postings on other sites about stop leak products like BarsLeak and a similar GM product (GM coolant supplement) as well.

Has anyone had experience (good or bad) using any kind of stop leak products with this type of situation? Input is much appreciated.

 

If used wrong it could plug up radiator or hear core tubes. The trick is to not dump the stuff straight into the cooling system. Take a 1/2 gallon of coolant/water 50/50 mix and pour the stop leak into that. Shake it up real good then pour it into the already heated up cooling system. Close the cooling system and go for a 10 mile drive. The worst case scenario is your heater core gets plugged up, but since you're under threat of having to change it anyway, you have nothing to lose by trying this.

 

Thanks for the feedback, there are over a half dozen BarsLeak products for cooling systems on their website, any recommendations which is the best option? The Liquid Aluminum Radiator Stop Leak looks pretty good though I know a lot of folks talk about the pellets, not sure which is better for the Exp. Heater core.

 

Very short term repair Stop Leak works well.Long term repair Stop Leak won't last. At some point in the near future after you use the Stop Leak, you still will have to replace/ repair the heater core.

 

The aluminum powder works the best and lasts the longest.

 

I have a 99 EB and had to replace the heater core i did it my self and looking back it wasnt that bad just a little time consuming, price on a lifetime core was 50.00 from oreillys and with some help from here everything went great, so if you want piece of mind forget the stop leak its for emergences not for the long haul jmo

 

I have a 98 Expy and I had to replace my heater core a couple of years back. It was going to cost me $1150.00 in labor for a $39.00 dollar part. I bought the part and set aside a weekend. I got up early on a Saturday, took my time, and removed the whole dash in order to get to the heater core. It took a couple of hours to remove the dash but a couple of seconds to remove and replace the heater core itself (two quick disconnect fittings). Got up early Sunday morning and replaced the dash along with hooking everything back up (air bags, etc.).

Now the funny part is ----I had 16 screws left over after I was finish, however, the dash has remained in place and the heater core has been working well to this day :-). Saved $1150.00.

 

Who hasn't had that happen to them! Well maybe 2 or 3 screws left over, not 16.

 

I don't know where the original poster is from, but when I was young and broke, we used to fix heater core problems by rerouting the cooling system to eliminate the flow of water through the heater core. We didn't have heat but when you can't afford to replace the defective part, a lack of heat was tolerable in the South. It beat the option of mucking up the radiator with stop leak and possibly causing engine over-heating problems.

 

I just replaced mine today. It started smelling funny a few weeks back, and I bought the heater core then from Autozone for 40 or 50 bucks for a lifetime warranty. I should have made the time last weekend, because last night while the wife was driving home, she had to roll down the windows because of the steam coming from the floor vents... She wasn't too happy. So I took the day off and tackled it. All in all, not too bad. There are a few things to watch for, and a few things that make the job easier. I took pics, and am planning to write up the process. I hope to have it done tomorrow or the next day. I will post a link when it is done. Started at 10:30 am, dash was out at 1:30, then only took about 30 mins to replace the heater core, another couple hours to reassemble. Hardest part, besides the time, is putting the quick connects back on the heater core. Oh, and 0 left over screws (almost lost one behind the heater core / evap box)...

 

Notice any improvement in the heat output?