new coolant leak

[dirtautoguy]

on my 1996 k1500 with 230,000 miles I recently found out that I have a new coolant leak. The leak is on the front driver side of the radiator and looks almost like it would be coming from the drain plug. I checked and the drain plug feels tight and the leak only seems to show up at first start up of the day. after that I cannot get it to leak to see where exactly its coming from. I checked for cracks around the upper radiator hose area and cant see anything, it looks dry. it looks like it wouls be coming from somewhere near the bottom of the radiator becuase I cant see where the coolant has ran down the radiator. the passenger side is almot completly dry and doesnt look like it is where its leaking.

the radiator is only 4 years old and I just did the water pump last month. any thoughts or ideas? I really dont want to replace the radiator could it be someithing else leaking? the bottom hose is new and the top is the original (ill probaby replace it pretty soon)

 

[jkeaton]

Try hosing it all off, starting it and then crawl up under there and see where its coming from. Kinda hard to guess otherwise without the truck in front of me, but that's what I'd do.

 

[dirtautoguy]

that makes sense. I was just hoping for a common easy fix that I could learn from someone elses experience. maybe Ill see if my collision repair teacher will let me pull it in the shop tomorrow and check it out closer.

 

[Ironhead]

Isn't the top rad hose connected at the op of the rad on the driver's side? That would be the first area I'd check out.

 

[dirtautoguy]

I have been watching it lately and I may have found it I am not positive yet though. so I took the radiator shroud off and could find anything, however I was focusing on the driver side since that was where the coolant was coming from. I couldnt find anything so I went to check the fluid level and noticed that around the spout of the radiator cap was a little wet. and when I took the cap off the plastic under the cap had a little sharp ridge like something had kind of scraped it. so I dried off everything that I could and cleaned off the plastic ridges and then sanded it slightly with 800 grit sand paper to smooth it out. it only leaked when the truck is run for the first time of the day. so on my way to school I will see if it is leaking again.

 

[dirtautoguy]

I havent had time to pull it into the shop yet but I think I will tomorrow. after further inspection when I had a moment it looks like it is leaking between the plastic tank and core. I will confirm soon as I can however if this is the case could a shop re crimp it or fix it and would it be worth it? or would I be better off to just replace it? I dont really want to pull it out twice if I can avoid it. also a shop replaced my radiator not me and it seems like the one I have has a thicker core than what I am seeing for replacements.

 

[dirtautoguy]

friday I pulled it into the shop and took a look at it. the problem was that it didnt leak. the only incriminating evidence I could find is at the bottom of the radiator near the oil cooler was a little bit wet like it had been leaking before. I went and rented a cooling system pressure tester in town to see if I could make it leak so I could find it. I pumped it up to 15 lbs and it held there for over 5 minutes and did not bleed off. So now I dont know what to do or think. the leak was leaking right behind the front bumber so it just about has to be the radiator. I dont plan on taking the truck on any longer trips any time soon but I am wondering if I should just replace the radiator. any advice?

 

[Ironhead]

Very mysterious. I am now wondering whether the liquid you noticed was really coolant? Did you give it a close examination, including checking for that sweet taste?

 

[dirtautoguy]

I thought it was strange to. I am pretty positive it is coolant. its orange in color and the only things around that area are windshield washer fluid (mine is blue) engine oil, and power steering fluid which none of them are orange and its watery not oily. and yes the orange stuff tastes like coolant so I am 98% sure its coolant....

 

[Ironhead]

AAArrrgh! Doncha hate it when it's a small, but annoying problem, and there's no explanation?

Interesting that the pressure test comes up with no leaks. Yet it's understandable that you would be very wary of a long trip in the truck without knowing what the problem is. Having said that, I think if you carry a container of coolant, going on a long trip might be a good way to see if there really is a bad problem. Stopping from time to time to check the coolant level in the overflow bottle, and keeping a good eye on the temp gauge all the time. If you go for such a trip, and there's no appreciable loss of coolant, then perhaps you can move on from this.

If that doesn't work for you, I would check the fluid cooling inlet and outlet points on the rad (trans and engine oil coolers, if there is one), also go over the crimp joints on both end tanks of the rad with a magnifying glass (difficult to get to), and also make sure that it is not leaking on the passenger side, then running over to the driver's side before dripping. The overflow tank hose is on the passenger side.

Finally, I can't remember whether you have checked the water pump weep hole. If the pressure test is done with the engine off, that leak might not show up, as the water pump was not turning at the time. Long shot, but hey! you never know.