Hi I have a 2007 2.2 HHR LT. The engine over heated, so I got to a gas station and let it cool down, put water in it. Got a mile or 2 and it started to over heat again. Called a tow truck and had it towed home (at a cost of $226 - $126 out of pocket).
Tried to find what was wrong and didn't. I drove to the store and it started to over heat again. Didn't drive it again for a few days, drove to the store and it wouldn't start. Had it towed home, wasn't even a mile away.
Started it the next day and noticed white smoke coming from the tail pipe. Checked oil & it was milky.
It is under warranty so I had it towed to the Chevy dealer. They found a blown head gasket and the heads are warped. They recommended a new motor. The warranty company sent a rep out to look at the car. They won't cover anything but the radiator fan - which is shorted. The heater core is bypassed. They said that the fault is either the heater core being bypassed or negligence on my part driving car while it was over heating.
My question is can a vehicle overheat because the heater core is bypassed on my vehicle?
I think the warranty company is trying to get out of having to honor the contract, which warranty covers the part that went bad - the fan - which I believe is the reason the car overheated and not the heater core, which should be covered under the warranty.

 

The heater core hoses bypassing the heater core would mean you would not have cabin heat!
The fan motor issue would cause the fan to not cool the engine but it is set to come on at 217 degrees or so
I sense you did not bypass the heater core or short out the fan motor!
But you did try and drive it and overheat it a few times
The car is under warranty, so you must have bought it fairly recently, I'm guessing at the dealer you had it towed to, they should have caught the bypass
If they certified the car in order to get the warranty then they should honour it and replace the engine.
Sorry you are in this pickle but it sucks that car dealers can do this and just shrug their shoulders and say " it wasn't us"

 

Bypassing the heater core should not have been a problem, as long as it was bypassed properly. Ie: it allowed coolant to flow, and was not blocked off.

continuing to drive it repeatedly knowing it was overheating - well that is probably a valid reason for disallowing your claim.

 

Judging by the wording of the Warranty as reported by lisasvette, I'm thinking it's an aftermarket Warranty offered by a third party. As I've said before, putting on my Retired Attorney's hat here, aftermarket/extended service plan type Warranties aren't worth the paper they're printed on.

The most egregious example was a Warranty offered by a now defunct company who's 100,000 mile coverage on the transmission only extended to the "Transmission Case" while excluding "Any and All Internal Transmission Components & Related Assemblies".

I've never seen a transmission case fail, unless the vehicle has had a frontal impact, which rendered the Warranty "Null & Void" of course.

As whopper stated, proper bypassing of the heater core would not have caused the reported damage, but it does beg the question of why the heater core was bypassed?

Cooling fans can fail, but they are there to provide airflow when the A/C is engaged, or when the coolant temp exceeds 217° in bumper to bumper traffic, or when there is insufficient airflow through the radiator due to low road speeds.

Simply put, the engine is "cooked", and in my opinion...the vehicle had issues before the overheating finished it off.

A bit more background would be helpful.