Oil change>overheat>head gasket>more

Here is the time line for my 2005 Honda Insight, all by Honda dealer:

8/10 - 33,800 Pre-Purchase Inspection = A+ Dealer #1

10/10 - 35,250 Oil Change - Dealer #2

12/9/10 - 36,775 Overheat #1 - spiking temp gauge, red for less than a minute. tech notes: coolant slightly low, topped off. pressure check - no leaks. bled cooling system. checked fans. head gasket suspected, could not test because of part for equipment on order.

12/24/10 - 37,000 Overheat #2 - parked for holidays.

1/8/11 - Overheat #3, on the way to dealer for repair.

1/14/11 - Found excessive gas pressure in cooling system. Removed cylinder head for inspection + repair. Changed oil + filter, fan switch. Replaced thermostat + thermostat switch.

Reassemble and recheck. OK.

1/15/11 - Driver noticed “auto-stop” function not working properly. Appointment for repair on 1/18/11.

Thank you for getting this far through my story.

Here are the wordy details:

Bought a used Insight with less than 34k miles on it.

For the first 2 months everything was fine. Felt like a brand new car. Had no problems but needed to do some minor things at the dealer; wipers and key remote, and decided to get an oil change a bit early on the 37.5k maintenance.

Immediately after the oil change I noticed my MPG drop significantly. I am new to this car ownership thing and was trying to see if it was me by driving differently and research what might have happened. It got worse.

Before too long the first overheat happened.

The dealer could not test everything the first time and after swapping the coolant they could not repeat the problem.

I could about a week later.

My questions are:

1. could the oil change have been the cause of the overheat?

the correct type of oil was used, not sure if they might have over filled it, as this car only takes 2.5qt., could .5qt have really caused such an event?

2. if the overheat was caused by the oil, or some other problem, the blown head gasket is a result of the overheat. is it true repairing it does not necessarily fix the problem? although it seems by changing the therm, switch, oil & coolant they are hedging all bets…

3. now that it is back together it seems to run a bit better. the MPG is still lower than my first experiences and the auto-stop function does not work. how far am I to go with this?

I feel they botched the oil change causing the first overheat and I have already spent $2k fixing their mistake.

How wrong am I?

Thank you for your time and kind responses.

The oil change and potential oil overfill (was it ever verified too high?) should have not affected the overheating issues.

The blown head gasket is related to the three instances of overheating you have had.

Don’t know or understand about the auto stop function, but it may not be related to the overheating incidents.

New thermostat, fresh oil, new coolant is pretty standard when these repairs are done. Fan switch (assume one for electric cooling fan) may have been the culprit all along.

  1. No, an oil change cannot be plausibly connected to overheating of your engine–unless you suspect that the car was sabotaged when it was serviced. And, by sabotage, I am referring to draining some of the coolant. I view this possiblity as highly unlikely. Is this what you believe may have been done to your car? If not, what do you think that the mechanic could have done in the process of an oil change to cause the engine to overheat?

  2. The breached head gasket could be the result of the overheating, or it could be the cause of the overheating. After the fact, it is difficult to determine cause vs effect.

If it has been properly repaired, and if you will immediately pull over and shut off the engine at any future signs of overheating, the head gasket replacement should be a permanent fix.

  1. Gas mileage is a function of many things, including how well the engine has been maintained, the driver’s driving style, and the conditions under which the car is driven. How far should you go with this? First, you should determine how much lower your gas mileage is, as compared to the EPA estimates for the car. And, how far you should go with the situation should also be gauged on the basis of whether the car is still under any kind of warranty.

Even if it is under warranty, getting satisfaction on a gas mileage complaint is VERY difficult, even on a new car.
On one that is at least 5 years old…not bloody likely, IMHO.

As to the auto-stop, that is probably having some impact on your gas mileage. If the car is under warranty, then–yes–you should persist in trying to resolve it. If the car is not under warranty, the repair cost could be rather pricey, due to the nature of the technology that is involved. How much are you willing to spend on this repair?

Since you are new to car ownership, please allow me to give you some advice that is very relevant.
Learn how to check all of the fluids under the hood of this car, and do that regularly.

In particular, check those fluids right after the car is serviced. It is possible to have too little or too much oil put in the engine when it is changed, but unless you take the initiative to check it yourself, proving negligence 3 months after the fact is not realistic.