Tracking down a coolant leak

[CaptainAtom]

Hi all, I'm try to track down a coolant leak. Now I up on stands and filled it with some antifreeze and turned it on and checked to see if it the water pump was spraying it and it wasn't so I don't think it's the pump. I took the tire off and got under it and there's a lot of residue and actual antifreeze underneath the reservoir and down underneath where the radiator drain plug is. With all that I'm thinking it could be the reservoir might be cracked or something. If anyone can think of anything else I should check that would be big help.

[onlinebiker]

It can be the burp tank. I just fixed one that was easy - the overpressure line ( on top, routed to the intake manifold) was simply loose. ( causing it to leak rapidly at first - slowing as the level goes down)

Best bet - rinse off all wet areas with water - and dry it off. Then pressure test either static, or by running. The source will be easier to find then.

[2NDSOUT]

In one of my cars, I had a small crack that developed on the UNDERSIDE of the Coolant Tank. It was a small 1/4 inch crack that was almost impossible to see, unless you REALLY looked for it.

I swapped it out with a used tank, and everything was good.

[CaptainAtom]

Much appreciated, now I have the repair manual, could you tell me what the burp tank is so I can find it in my manual? Also is there anything I can put in the reservoir besides coolant to try and find the leak? I really don't want to spend more money on antifreeze if I don't have too. Again your help is much appreciated!

[trottida]

Originally Posted by CaptainAtom

Much appreciated, now I have the repair manual, could you tell me what the burp tank is so I can find it in my manual? Also is there anything I can put in the reservoir besides coolant to try and find the leak? I really don't want to spend more money on antifreeze if I don't have too. Again your help is much appreciated!

He's referring to the coolant reservoir where you would add coolant. The small return line into it at the top towards the firewall.

[CaptainAtom]

Oh ok thanks, that makes sense. Again thanks, I'm not the most mechanically inclined so I really don't know the lingo so to speak. Much obliged.

[alordofchaos]

If you are going to flush it after you fix the leak, hose water is fine for finding the leak.

Otherwise, I would use distilled water at roughly $1 or less a gallon. Then when you find the leak and seal it - drain the system, buy 1 gallon of pure (undiluted, not pre-mix) antifreeze.

Fill with 1 gallon undiluted antifreeze, top off with distilled, and you end up with roughly 57/43, a decent mix for most of the US

[Melissa_M]

Originally Posted by alordofchaos

If you are going to flush it after you fix the leak, hose water is fine for finding the leak.

Otherwise, I would use distilled water at roughly $1 or less a gallon. Then when you find the leak and seal it - drain the system, buy 1 gallon of pure (undiluted, not pre-mix) antifreeze.

Fill with 1 gallon undiluted antifreeze, top off with distilled, and you end up with roughly 57/43, a decent mix for most of the US

Do not add a ' stop leak' product.
The water pump has weep holes but that drips down onto the frame (?) and can be hard to spot.
The drain plug could leak.
The hoses may leak, or just where the hose/clamp connection is.

[Saturn Night]

Originally Posted by CaptainAtom

Much appreciated, now I have the repair manual, could you tell me what the burp tank is so I can find it in my manual? Also is there anything I can put in the reservoir besides coolant to try and find the leak? I really don't want to spend more money on antifreeze if I don't have too. Again your help is much appreciated!

The terminology used in repairs manuals can vary, depending on which author wrote the manual.

FSM, I think, refers to the tank as the "expansion tank".

Other names can be, "Overflow reservoir", "Overflow Tank", or "Coolant Reservoir".

There are three possibilities, with the symptoms you have described.

The pressure cap may have failed.

To test this, idle the car with coolant level at the "Full Cold" mark. Allow the engine to idle until the temp gauge gets to around the 5/8 mark. You will start to see coolant seeping from under the cap, and down the side of the tank.

The other two possible causes have already been covered, which are the aeration line being loose on the top of the tank, which will cause a seeping leak at any temperature and the engine running.

And, a cracked reservoir, which may only start out leaking under pressure or will leak even when the engine is off(from gravity).

Filling the reservoir, and allowing the car to sit overnight on a level surface, should be able to identify if the tank is leaking. You can also drain the tank and remove it, to visually inspect it for cracks.

And listen to Melissa M, by not adding any type of "stop leak" products. "Stop Leak" should only be used, when the symptoms match the description for the leak you are troubleshooting.

[Jon Boy]

In my experience, the quickest way to find a coolant leak is to put some UV tracer dye in the expansion tank, drive it around a bit to let the dye flow through the whole system, and then use a UV flashlight to see where it's coming from. It makes it really easy to see the source of the leak.

[Zeebins]

^^I agree with the idea of using a uv dye. I used one before to find an oil leak and it worked just fine. Make sure you read the bottle though of whatever your using. Some dyes I've seen arent compatible with dexcool.

[Jon Boy]

Yeah, I should've mentioned compatibility. I had to hunt around a bit to find some. I think I ended up getting it from Amazon along with a little UV flashlight for around $10 total.

[CaptainAtom]

Cool thanks for all the help! Now can I get the UV dye at somewhere like AutoZone or do I need to go online to find it?

[fdryer]

Yes, you can buy cooling system dye from most auto stores but check online first or call ahead. Be aware, one brand of dye isn't compatible with dexcool anti freeze. If you're using dexcool, this dye is not recommended. If you're using other brands of antifreeze, try it. The other alternatives to look for cooling system leaks is either with a fully warmed engine or pressurizing a cold engine using a kit borrowed from AutoZone. A hand pump with pressure gauge, hoses and fittings to match radiators or coolant container caps allows pumping up a cold system to operating pressures to find leaks without being scalded with hot coolant or burned on a hot engine.