Car Mags: Slow Coolant Leak Fixes

[HankScorpio]

My '15 GMC Sierra has a slow coolant leak. A quick search says there are several products out there that you simply dump in the reservoir - K seal, Bar's Leaks tablets and liquid. Curious how well these work and if its as simple a fix as I'm hoping. Any rec's for what works is appreciated.

[tBatt]

Where's it leaking from? Hose, radiator, or block? The problem with that stop leak stuff is it's designed to plug small holes. Problem is your entire radiator is a bunch of small veins and if you use stop leak or whatever you're at risk of then plugging entire veins in the radiator potentially causing overheating issues.

Honestly the best thing to do is find the damaged part and replace it.

[hawkgt]

Honestly the best thing to do is find the damaged part and replace it.

dont dump that shit in, long tern no bueno

[El Chupacabra]

X2 on finding the leak. I just used a pressure tester kit from my local Autozone (free loaner tools) to track down a slow leak on my 2000 Sierra - turned out it was just the cap on the pressure tank, so easiest fix possible.

[Vt-Freeheel]

A '15 shouldn't be leaking, find the source of the leak.

[detuned]

find the leak, then repair it

[3PinGrin]

My '15 GMC Sierra has a slow coolant leak. A quick search says there are several products out there that you simply dump in the reservoir - K seal, Bar's Leaks tablets and liquid. Curious how well these work and if its as simple a fix as I'm hoping. Any rec's for what works is appreciated.

If you bought any of that shit, throw it in the garbage. Have you even looked to figure out where it's leaking?

[I Skied Bandini Mountain]

That shit is for broke ass students trying to keep their beater alive with no money.

Fix it right.

[I've seen black diamonds!]

Don't know anything about that engine, but a slow coolant leak can sometimes indicate a head gasket problem causing too much pressure in the cooling system.

Cars often have parts that are know to fail early. Could be as easy as the cap on your coolant reservoir or the reservoir itself. Check on a forum specific to your truck to see if people have had similar problems. That can give you some places to start looking first. That's your best bet for a quick easy fix. Pouring in any of the crap you mentioned isn't an option.

[HankScorpio]

If you bought any of that shit, throw it in the garbage. Have you even looked to figure out where it's leaking?

No, I wouldn't dump anything in there unless I knew it would work. I topped off the coolant 4-5 days ago and its sunk about a 1/2 in. below the fill line so I'm assuming its leaking. No clue as to where its leaking, I'll have to take closer look at it this weekend.

Truck runs fine, no issues with overheating or steam piling out of the hood.

Looks like this won't be a simple fix. ISBD - I'll def be digging through some forums to help narrow it down - hoping the head gasket isn't the issue.

[huckbucket]

No, I wouldn't dump anything in there unless I knew it would work. I topped off the coolant 4-5 days ago and its sunk about a 1/2 in. below the fill line so I'm assuming its leaking. No clue as to where its leaking, I'll have to take closer look at it this weekend.

Truck runs fine, no issues with overheating or steam piling out of the hood.

Looks like this won't be a simple fix. ISBD - I'll def be digging through some forums to help narrow it down - hoping the head gasket isn't the issue.

Can you smell it when the engine is hot suggesting it's leaking onto an a hot engine (exhaust, etc)?

[El Chupacabra]

Do a pressure test. Very easy.

[HankScorpio]

Can you smell it when the engine is hot suggesting it's leaking onto an a hot engine (exhaust, etc)?

Nope. No smell, just noticed a bit of steam coming off the radiator when I parked it yesterday.

[huckbucket]

Get it hot again and track the origin of the steam?

[XXX-er]

I wouldn't add that stuff, why back in the day out on the farm we would just get a handful of oatmeal from Ma in the kitchen

[El Chupacabra]

DO A PRESSURE TEST.

[HankScorpio]

Get it hot again and track the origin of the steam?

Yep, that's step 1. It'll be fun to work on the truck when it -10 tomorrow morning.

[snowaddict91]

Yep, that's step 1. It'll be fun to work on the truck when it -10 tomorrow morning.

On the plus side, metal contracts when cold. May make it easier to find your leak.

Look for dried, white, chalky residue around all hoses and radiators. That is dried coolant. Hoses and their connections/junctions are the most likely culprit on newer vehicles, especially if it has quick connects with o-rings like most Fords.

[ak_powder_monkey]

No, I wouldn't dump anything in there unless I knew it would work. I topped off the coolant 4-5 days ago and its sunk about a 1/2 in. below the fill line so I'm assuming its leaking. No clue as to where its leaking, I'll have to take closer look at it this weekend.

Does not sound like your coolant is leaking. The reservoir is not supposed to be full, it is in fact there to catch the excess coolant after it expands in the engine do to thermal expansion. I imagine this engine has some sort of bleed valve to keep your coolant level correct. Just make sure to have a gallon of distilled water around just in case.

[XXX-er]

the rad is suposed to puke water into the overflow res when hot and then it gets sucked back into the rad when the engine cools

so the level in the tank will change depending on if the engine is hot or cold but the level should always be the same for a hot engine and the same for a cold engine

[stradissimo]

DO A PRESSURE TEST.

AutoZone will lend you a coolant pressure testing kit for free. Do it!