Cadillac Catera and Cimarron Forum Discussion, strange coolant loss. Can't find any culprits. in Past Cadillac Vehicle Discussion; So like title says I lost a little bit of coolant in a way where looks like an small explosion ...
So like title says I lost a little bit of coolant in a way where looks like an small explosion under the hood. I inspected all hoses for cracks n leaks with no result, checked the reservoir no cracks anywhere. Before I got home I didn't have any smells or warning lights no drastic temp chance while driving, nothing. I have no leaks under car. I had just above half full in the res. So I topped up and started it with no leaks or spraying n no warning lights.
Im so confused, what would cause this.? Any and all comments appreciated.
Re: strange coolant loss. Can't find any culprits.
The heater bypass valve is a very common problem in Cateras. Follow a heater hose to the back of the engine and it will enter the plastic valve. It bypasses the heater core when the A/C is on full in the summer. Depending on the water flow through the valve, it may or may not leak at any given time. Sometimes it drips on the exhaust and instantly vaporizes so it doesn't show as a puddle under the car.
Could also be the Aux water pump under the coolant reservoir. Kicks in to increase water flow through heater core. Possible that it only leaks when the heater is on full.
Just extra info to this thread:
I had coolant lost too and couldn't track it, I only had a smell of it on hot engine and had to add coolant every 2 weeks, no spots on the ground or drips was found. I was replacing my oil cooler and when looked on thermometer I found a small leak from gasket, coolant was leaking down to oil pan, under cams covers, exactly between cams. While it was leaking on hot block, coolant was evaporating.
If in case the heater control valve (HCV) goes bad, go with this mod that I did on my car and so far no problems. I did this modification in 2009 and it's been over 4 years and still functioning well.
Are u talking about mod where moved HCV closer to coolant tank? If yes that was really good idea.
Mine when out 3 times. Twice on used from junk yard, then I got one over ebay for around $25, didnt last long. Then I got second one for around $30 over ebay too, different brand then first one but now already two years pass and its working fine.