Hi,

I got a coolant leak but am having trouble finding out where its coming from. I just bought a 2015 Chevrolet express 2500 base model USED 160k miles. The PO had replaced the radiator with a NEW aftermarket one. It's aluminum or something better (so he said) When he installed the radiator, it looks like he took off the OEM spring clamps and put in regular hose clamps in some spots. The rubber hose going from the lower radiator to the t stat had coolant seeping from it, so I tightened it up. However there is more coolant dripping on the OTHER side of the water pump, and I am thinking it's come from the weep hole.

The reservoir was filled to the top max COLD FILL line and now has fallen under. IT appears to leak a little even with the vehicle not having been run for days. I am starting to get a little worried that the PO might've pulled a fast one on me, because I am worried he did an improper install and might have royally screwed something up. When I bought the van i did look at the car fax, but didn't study it enough. I just realized that this vehicle was probably sitting on a used car lot for a year. This was during 2022 and the PO informed me that when he bought it they had put in a cheap catayltic converter that failed on him. He bought a nice one by the looks of the welds and materials, looks very high quality, but where I am getting at is that I am almost thinking that at the used car lot someone had stolen the cat, and during that time they couldn't get a replacement to sell the van and so it sat. I am hoping they at least ran the van. I know often these vans sit for years, in fact I watched another at another local use car dealership and it's been sitting for a year. PEople have trouble backing them up, etc.

Anyways what I am getting at is I really hope I did not buy a lemon, and he did not use some kind of rad stop leak just to get a quick cash grab. PO told me old rad rusted out from the bottom, so I guess I should've asked about the rest of the system. PO never drove this van much, mainly because his delivery business failed and it's an expensive rig to drive(makes sense though)

TLDR:

why is the coolant dripping from the t stat inlet hose and from the other side of the water pump? Any ideas where the weep hole is? I can't see a thing everything is so compact and dense. I tightened down the t stat inlet house (radiator lower hose BIG RUBBER ONE) but NOT sure if that made an impact. IT leaks even days after the vehicle has been run. The leak is a slow drip but I've already gone below the cold fill line on the reservoir. It doesn't appear the belt was every changed, so good chance the water pump never has been either. 160k miles on the ODO.

 

If you are seeing coolant from the pump, that would be what I would change next and maybe replace the hose that's dripping as well

 

I'm always a little leery of a vehicle being sold with a new radiator. I wonder if the radiator was replaced because a diligent owner noticed a small leak or of someone drove it dry, overheated it and are now trying to patch up damage and unload it. I've seen a few different cars overheat for different reasons then spring leaks from the pump weep hole right after. I don't think you can see the actual weep hole but it will look like it's leaking from the body of the pump and dripping down.

You can get a cooling system pressure tester from some auto parts stores on their tool loan program. It's pretty simple to use. It will have a bunch of adapters, one of which will attach to your radiator fill neck. You attach the included hand pump and pump it up to about 16psi (it has an attached gauge). With the system pressurized it will leak just like the motor is running and hot. You can safely dig around in there and find the leak.

If it were me I would replace the pump, hoses and thermostat just to be sure.

 

I tightened up the hose and now it's not leaking. Yeah a lot of people were trying to get him to come down on price. He came down a bit with me but hopefully he didn't sell me a lemon. I'll keep an eye on the weep hole. For now, after tightening the hose, it's not leaking. No idea why the weep hole would leak, but I did read something about how if any of the outlets to the water pump aren't sealed, you can get a leak. PO wasn't the best mechanic as I posted above, and he shouldn't have used hose clamps where he did.

Any of you guys know why the coolant resovoir says "inlet thermostat improper fill could lead to engine damage". The owners manual says that when the vehicle is cold, the coolant should be AT OR ABOVE the cold fill line. I am thinking about slightly going above the cold fill line just in case of another leak.

 

The only issue that could be caused if the reservoir is overfilled is it splashing out when you hit a bump. Not a big deal. Spring clamps are nice because when the rubber relaxes with time they stay tight so you don't have to go back and retighten. If you use them do yourself a favor and get yourself some cable hose clamp pliers. I should have gotten some long before I did

 

OK, I wont go crazy adding coolant. Just a little over just in case. Also If he did overheat the van would I know about it? (other than a leaking weep hole, which seems to have stopped for.). Ran great during a test drive, sounded solid, shift smooth. I had some family even drive it and they gave the OK. A compression test would be tough since the spark plugs are hard to get to. I did pull a couple and look, seems fine, other than one plug was kind of weird, had the proper gap but the metal part that hangs over the electrode was a little off to the side, if that makes any sense. I guess I could go to auto stone and get a compression tester, but at that point I am going to fork out the big bucks for all new AC delco plugs and wires.

I guess if it over heated and he shut it down right away, it would be fine. I thought newer cars (in this case a 2015 chevy express)the software automatically prevents you from driving to the point of destroying the engine. IT'll force you to cool it down, But I didn't see that mentioned in the manual so maybe it doesn't have it.

Also is a little bit of moisture from a weep hole on these vans a big deal? or any kind of visible coolant up there a big no no? no more leaks on the ground

 

no moisture, no coolant, but there is a visible redish sticky goo underneath the water pump. Guessing the antifreeze got glued there from heat? If the water pump was leaking but not touching the ground, I might've not noticed it when I did my pre purchase inspection. So it's possible it was weeping when I bought it, I just didn't notice. That water pump is up in there and hard to see, and that's the only spot that looks reddish sticky, aside from a little sticky spot on the AC pulley below (you know the pulley with it's own belt) The line leak was definitely loosing a lot of coolant.

 

I wouldn't worry about if it was overheated if it's running fine. Nothing you can do either way but it's probably fine. I don't know of any visual inspection that will determine if it's been overheated. I would think there would be warning lights and an alarm if it started to get hot so hopefully it's not an issue.

It's not normal to see any coolant anywhere. If you see fresh coolant it needs to be addressed. What you're seeing is probably residual from the leak. Coolant is slower to evaporate than water so a puddle hiding somewhere can fool you into thinking it's a leak. I would carefully spray the whole area with a hose to wash it all away. If it's congealed or crusted clean it up. Once it's all clean and dry you'll know that any new fluids are from an active leak.

I'm someone who regularly cleans and wipes down the engine bay on every car I own. It's a bit **** but I've caught many problems over the years before they became failures.

 

Yep. IT;s leaking again from under neath the water pump, directly underneath where the fan axle comes out of the water pump assy. I guess it was the water pump all along, since what I read is that that area is where the weep hole usually is on a vehicle.. it's really strange how these weep holes work. I didn't have the vehicle on for two whole days and only ran it for 20 mins before those two days, and all of a sudden a family member noticed a pretty big puddle underneath the vehicle.

IS it normal for these weep holes to leak with no activity? can you explain how the GM chevy vans work or is the same like most water pumps?

oh and for the replacement water pump AC delco is best? And for the thermostat get the GM one correct?

seems like it was leaking everyday while driving it, but it was boiling off and not leaving residue. really strange.

 

As the pump worsens it will likely leak more. Also once run and the system pressurized, it will contnnue to leak sitting as the pressure drops.
I always buy lifetime warranty pumps at local store or rockauto because I keep my rides forever and this is a part that needs changing occasionally. My 93 Sub has 350k on it and I just put in my 4th pump this summer. Use distilled water with your antifreeze, not tap water, things last longer.