Doug,

Generally, you do not want to mix Green coolant with Red GM Dexcool. They are not the same and the green coolant will not last as long. Green coolant should be changed every 30,000 miles, while you can get 75,000 + out of Dexcool. The cooling system will probably be open during the repair, and it would be a good time to change the fluid anyway.

However, you have a big leak and as hicksvilleshick noted, you really need to take this seriously or risk major $$$. I would try and locate the cause of your leak before you try and drive the truck. If you don't, any coolant you put in the system may be gone within a block of your home. If the leak is small and it can be contained, you may be able to drive it, but I would take a very conservative approach with this problem.

Good luck

 

And when you buy 50/50 coolant, you are buying two qts of water. Expensive way to buy water.

Buy straight Dexcool antifreeze. You'll need a 50/50 mix, so find out the capacity of the cooling system and divide by two and this is how much Dexcool you'll need. Put it in first and top off w/ distilled water. Then fill the reservoir to the Cold line and check after a Hot/Cold cycle and fill back to the Cold line. If the reservoir is empty, you'll need to do this again and repeat 'til the coolant stays at the Cold line when the engine is cold.

 

I bought some DexCool and after mixing it (with tap water 50/50), it basically dripped right out into my driveway (as I suspected). I crawled under to see if I could identify the source but it was very difficult to find. I don't see any disconnected hoses or immediate leaks from a hose connection anywhere that's obvious. It is definitely coming from some area deeper up beyond where I can see - I'm no mechanic but I am a YouTuber and from my research it appears as though it is dripping right from the water pump seal - and I mean dripping!
The water pump replacement is beyond my repair ability (at this time) so I am taking it in on Monday to my mechanic.

Questions:
1) Does this sound like the correct diagnosis - water pump seal failure?
2) How much would I expect a repair/replacement like this to cost? ballpark
3) I need to drive about 5 miles to the mechanic - Ok to do? Fill coolant before I go?
4) 50/50 DexCool and tap water or distilled water? I have read some places saying tap is fine and others warning to use only distilled. I figure tap doesn't matter too much right now because it's all spilling out in my driveway but for the future. . .?

Thanks guys

 

Doug,

Since the leak is severe enough that when you pour coolant into the system, it leaks out right away, you should have the truck towed. The cost of a water pump is pretty inexpensive when you compare it to a new engine.

A new water pump is going to be around $110. It will be around 2.5 hours to replace. However, you may have more problems than just the water pump. Try don't normally leak the way you are stating. It could be a number of problems.

It would be best to used distilled water. Unfortunately, you never know what minerals are in your tap water. At this point, the system will need to be refilled and the mechanic will know what to do.

As many on here have said, it would be best to not drive it.

Hopefully you can get your truck fixed soon and there isn't too much damage.