Diappearing Coolant
It takes alot of coolant to be gone before it overheats. He's losing a little bit each time he drives it, so he's checking it often. Let it go for 2-3 weeks and maybe he'll start to run hot. Engines will run normal temps with alot of coolant missing. If the cap just started to lose its tension, he can go through this for months before it totally lets go and blows coolant out quickly.
The Best V8 Stories One Small Block at Time
You need to get a pressure test done, thats it. You will find the problem. Its cheap and you can have it done today almost anywhere.
You could have a tiny crack somewhere too. Its just wierd that it will leak out when the engine is not even started, thats some wierd ****.
1. It will hold the pressure, or how much.
2. Where it leaks, if it does under those conditions.
I have seen them leak only cold, only hot, and intermittently. In those cases, it's usually a water pump. A reservoir leak is rare except in cases of:
1. An impact
2. Leaky battery (this is pretty common)
Your cheapest fix is to get a new reservoir and radiator cap. Replace, refill, bleed, and watch it. If that doesn't do it, water pump is it, almost 100%.
I may have missed it but did you confirm no coolant in oil or oil in coolant?






