Just looking for a gut check.

I have owned my 2006 LR3 for 6 months. It has 137K miles and haven't had any problems with it. I did the first oil change and this time my girlfriend suggested using her shop which is a general import garage.

They did the oil change and inspection. Topped off the fluids. The next morning, first time I drive it, we hear a pop and the car looses power. Soon after the coolant blows out. There temp gauge never went above half way. I open the bonnet and notice the coolant reservoir had way too much in it and was filled to the top. I got the car home and couldn't start it.

The shop paid to have it towed in. They were able to start it and found the thermostat near the intake manifold had blown. $430 repair.

Does this sound like a strange coincidence or is it possible that filling up the fluids wrong could have messed up the pressure and blown the valve?

 

Probably just a coincidence. If they overfilled the coolant reservoir, the pressure might build up, but your coolant reservoir cap is designed to release that excess pressure once it gets to a certain point. There's always the possibility that your reservoir cap was bad, but I think you probably just had an unfortunate thermostat failure. I was going to say that $430 sounds pretty darn steep to replace the thermostat, but I suppose they probably replaced the whole thermostat housing... in which case the cost sounds reasonable.

 

Its called an expansion tank for a reason. As coolant heats up it expands and that tank is where it goes. If it is full, the coolant has no where to go but out. The caps are vented, but they were designed to vent air, not really coolant (although they can).

On the other hand, the coolant crossovers (aka thermostat housings) do fail, and often times without any outside influence. So whether it was the other shops fault or not, who knows. Even if it was because they overfilled, a healthy crossover would have survived an overfilled system, so it was likely going to fail anyway.

I guess in a way, its good that it happened now then while on a trip or in an emergency.

With that said, hopefully they replaced the coolant bleeder on top as well. Either with a new bleeder or a brass connector. They also like to "pop" and spew your entire cooling system on the ground. If not, you may want to consider doing that as well.

 

As old as your truck it, the float in your expansion tank will likely go next lol
You'll be stuck with a nagging "low coolant warning" on the dash intermittently when your coolant level is fine.

Might have been a good time to pay the $55 to get a whole new expansion tank / bleeder / float. They redesigned the tank a bit as well