Author Topic: radiator stop leak  (Read 2365 times)

Offline Elroy

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radiator stop leak
« on: September 05, 2021, 09:23:36 PM »
Here's a little Elroy story about radiator stop leak for your entertainment. This little adventure concerns his 2004 GMC Canyon with the "big" 3.5 liter, straight 5 Cylinder. Bought it new. Overall it's been a good vehicle even though it's had a few problems. It came factory filled with Dexcool antifreeze. Supposedly good for 5 years / 150,000 miles. Elroy pushed the original coolant for 7 years. Mileage was only about 60K. Flushed it out and refilled it with fresh Dexcool. Less than year later the water pump started leaking. Rip all that apart and installed a NEW, made in China pump from AutoZone and reused the 1 year old Dexcool. All is good for one more year and then the pumps starts to leak again and the temperature is hot. Rip all that crap apart a second time and discovered the pump was NOT leaking, this time it was the thermostat housing. These engines have the thermostat in the lower radiator hose and they're a real bitch to service through the left front wheel well. Talk about a PITA ! Anyways got that all buttoned up and all was good until the next coolant flush. So two year ago it was flush time again. less than a month later the dam radiator starts leaking. Not a problem.....................that's what they make stop leak for. That stopped the leak .......................for a while. So this summer Elroy started smelling anti-freeze and there's water on the garage floor in the morning. That coolant was only about two years old and that stop leaked worked last time so lets try another bottle.

That was a mistake

Next thing you know the temperature gauge has a habit of reading real HOT and the leak just gets worse. So Elroy bit the bullet and installed a new radiator. That was an adventure in itself but Elroy was NOT looking forward to servicing that dam thermostat again. Did Elroy mention how difficult it was ?  What a PITA

Anywho, got it all buttoned and filled it with straight water. left the old thermostat in. Well like magic the leak is gone, the temperature is normal and best thing is, the thermostat is is not sticking.

It's got one of those aluminum radiators with the crimped on plastic tanks. So this afternoon, Elroy pried open the aluminum crimps on the old radiator and removed the plastic tanks to inspect the core. Well it wasn't running hot because of the leak or Elroy's worry the stop leak stuck the thermostat closed. NOPE about half the tubes were plugged up. Guess that's what two bottles of stop leak does. It stopped the leak for a while but boy that second bottle plugged it up but good.

So the lesson here is.........................if you use stop leak, it's only a temporary fix and it makes a mess of the cooling system.

Elroy is going to drain and refill with water every couple of weeks until cool weather starts then hit it with a fresh fill of anti-freeze. I just hope that dam thermostat doesn't fail or leak. Did Elroy mention it's a real PITA to service.
« Last Edit: September 05, 2021, 09:27:42 PM by Elroy »

Offline goodfellow

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Re: radiator stop leak
« Reply #1 on: September 06, 2021, 07:12:40 AM »
Good story Elroy. I've used stop leak in a pinch. but usually serviced the system within a week or two after that. It always looked like mud in in the system after adding the stop leak. Glad you were able to get it back on the road.

Offline DeadNutz

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Re: radiator stop leak
« Reply #2 on: September 06, 2021, 11:21:15 AM »
Thanks for the story Elroy. My old 55 Ford F-100 kept running quite a while on a steady diet of Bar's Leak in the radiator. I needed the truck nearly every day for work and could shut it down for a few days to get the radiator fixed. Finally had a chance to get the radiator fixed after many cans of Bar's and it never plugged the radiator.

Offline bonneyman

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Re: radiator stop leak
« Reply #3 on: September 06, 2021, 06:49:33 PM »
The B-man can relate to Elroy.

My 2004 Astrovan 4.3L V-6. Just turned 150,000 miles great truck, great motor. But some of the other parts are crap and puke junk! Radiator is one of those aluminum with plastic endcaps. What a crap design! Asked if there was a better OEM equivalent or HD version? Nope, all they make is what I've got. On my third radiator (original and two replacements)
Plastic thermostat body developed a crack. Slow leak didn't leave any residue on the garage floor, but leaked enough where engine started running hot. Mechanic tells me this part failing could've wrecked the engine. Not in stock locally, had to order one from LA. Cause the truck is "old".  :41:

I now check coolant level basically every other day and have a gallon of premix in the van to top off if on the road. What a joke.

Offline slip knot

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Re: radiator stop leak
« Reply #4 on: September 06, 2021, 07:05:51 PM »
If it was that crappy red dexcool it probably wasn't the stop leak but the coolant. Seems the red coolant doesn't like air in the system which your leak created. air and red dexcool makes sludge. BTDT. Ran green in it for the rest of its life.

Offline Elroy

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Re: radiator stop leak
« Reply #5 on: September 07, 2021, 04:23:25 PM »
If it was that crappy red dexcool it probably wasn't the stop leak but the coolant. Seems the red coolant doesn't like air in the system which your leak created. air and red dexcool makes sludge. BTDT. Ran green in it for the rest of its life.
\

Well Elroy filled it with that "orange crap". Years ago Elroy had the habit of flushing systems with Tri-Sodium Phosphate. It did a good job of cleaning out the crud but it this situation, Elroy had a clean, NEW radiator and was hesitant about the TSP reacting with the "new" coolant chemistry. Time will tell.