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Discussion Starter #1
Hello folks,

New to the forum and first post so please excuse me if I've not correctly followed the community guidelines in posting. I own a 2015 ATS 3.6L RWD and live in Dubai, I'm therefore limited to readily available product locally.

I've unfortunately got a leak in my car's radiator and wanted to ask for the communities feedback and suggestions on fixing the problem. I've managed to find STPs radiator sealer here at a local hardware store and was thinking about using this product to try and fix the issue - as a first fix attempt, and then monitor the situation and assess if the radiator needs replacing?

Here are some further details to help better assess the problem
  • I filled up the coolent from empty in the resovoir 2 days back and after checking the level again this morning, I've noticed that it's at now sitting at half.
  • the temperature needle doesn't seem to be increasing even after driving around this morning for about 2 hours. Bear in mind that Dubai is considered to be an extreme weather climate area.
  • the leak was noticed by GMs authorized dealer here in Dubai and had reported this to me about 2 months prior. I then monitored the temp gauge and saw that it runs at its usual temperature with out any noticiable movements to the needle. I put the fix on the back burner untill I've had time and money, which I do now hence why I'm here asking for help.

It would really help to know if A) a radiator seal will fix this issue and B) if STP Radiator seal is a product suitable for the car's engine.

Thanks in advance.
 

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2013 ATS4 3.6L Premium
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253 Posts
I would not recommend any such "fix" as it's temporary, at best. What's more, is that it may "seal" something it's not supposed to, which will further reduce the performance of the radiator.

The best solution is to get a replacement radiator. It doesn't have to be a GM one, as most competent radiator shops (I expect you must have some due to the climate) must be able to repair or rebuild it. Even if they replace the entire core with a non-GM one, you'd be better off. Worst case, they can pinch and weld off the bad section, if it's small enough.

My bigger question is, are you sure the radiator is where the leak actually is? The leak could be in many other places (worst case, could be a leaking head gasket)... so that should be repaired properly, not with a bottle of goo.
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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As long as the cooling system has somewhere near the correct amount of coolant in it the engine will run at the correct temperature as set by the thermostat. If the coolant level becomes so low that the water pump loses pumping ability then the engine will - will - overheat.

I agree with the above post - find and repair the leak, without using pour-in sealers.

There IS a limit to how large a weep/leak can be temporarily patched with radiator sealants.

For cooling system parts, try www.rockauto.com
 

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2014 ATS 3.6 Premium RWD, 2016 Corvette Z06, 2018 GMC Sierra Denali 2500HD Diesel
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As others said, get it fixed properly. Those stop leak quick fixes are designed for "beaters" owned by high school kids that are soon destined for the junk yard.

First, find out for sure where the leak is occurring. It could be one of the problematic fittings that are prone to failure and leakage but very inexpensive to fix properly, it could be a water pump seal going bad (you will see coolant at the weep hole in the pump), or a pressure cap that is not sealing properly. IF there is a leak from a failed radiator seam or other somewhat unusual failure for a car this age, have the cap on the coolant reservoir tested to ensure it releases pressure at its calibrated point because if the cap fails to allow the primary system to vent when it should then pressure goes excessive and the system WILL find a place to bleed off excess pressure.

Don't go too much by the coolant gauge because unfortunately in recent years GM has "dummied" the coolant temperature gauge in many of their vehicles so that once the car is in the normal temperature range the needle stays in one place even though the temperature varies a lot and it won't indicate out of the normal range until the coolant temperature moves well above the typical operating range. Be extremely careful when driving an engine that is low on coolant; the temperature gauge and thermostat will not operating properly when they see steam instead of liquid and a severe overheat can be very expensive including such problems as a blown head gasket (expensive) or damage to the head(s) which is far more expensive.

Once the system has been run too low on coolant the "degas" system which provides for overflow recovery AND purging of air from the system will take some time to remove all of the air. This system was designed to be simpler to deal with than the purge valve near the thermostat of many past cars that required what GM referred to as a "special coolant fill procedure" but the trade off is that it takes longer to remove the air. So once you do major work on the cooling system you will have to closely monitor the coolant level for several days (or weeks) as it goes through numerous heating/cooling cycles and the level will drop as air is removed from the system. GM's current L5P "Duramax diesel" engine is notorious for this and sometimes a low coolant warning will happen several thousand miles into initial operation; my 2018 was just over 1,000 miles before the coolant level stabilized and with most engines that would mean a leak but the complex plumbing in this one with an oil to water heat exchanger, water cooled turbo center bearing, and dual thermostats with different temperature curves makes it the nature of the beast for this engine. The 4 and 6 cylinder engines used in the ATS are much quicker to purge and if the coolant level doesn't stabilize after 10 good heating/cooling drive cycles then something is still wrong.

Again, don't put magic additives in the engine unless you feel it is nearing end of service life and not worth fixing. I seriously doubt that applies to your ATS. If your shops in Dubai are anything like the franchised GM dealer network here in the states then you are far better off going to a good independent shop with competent techs. There is nothing special in the technology of the ATS cooling system that makes it different from other modern vehicles.

Good luck!

Rodger
 
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