Side Effects of Hypermiling?

[johnnyte]

I've been lurking out here for a bit and picking up some really good info, but I have a big question.

I drive an '01 Civic EX. Without any extra effort I had been getting ~40mpg. After practicing some of the techniques I've found out here - the biggest being killing the engine and coasting - it looked like I was well on my way to a 50+ tank. Then the check engine light came on - misfires on 2 cylinders, the next day it started overheating (and I nursed it home and then to the shop stopping along the way to let it cool). The diagnosis was a cracked head.

The mechanic said in 20 years he had never seen a Honda with a cracked head.

So, after throwing a bunch of money at it I'm back on the road - but I'm hesitant to do anything that could be considered out-of-the-ordinary driving.

Is there any way that the cracked head could be related to coasting and restarting with the clutch?

Thanks,
J.T.

[dosco]

Originally Posted by johnnyte

Is there any way that the cracked head could be related to coasting and restarting with the clutch?

Bump starting shouldn't be a problem.

Is it possible you had some other problem that you weren't aware of ... perhaps a bad thermostat or water pump?

I once owned a 1993 Saturn SL2. One day I smelled coolant and noticed it dripping from the plastic side of the radiator (the car had a metal radiator core and plastic caps). So I changed it out, and then drove cross country (from Phoenix to Maryland). After a couple of weeks in Maryland, the radiator blew up one day on "the Beltway." I nursed her home.

The mechanic found the thermostat had failed shut, effectively reducing the cooling capacity by some ungodly amount (probably 90% or more).

Got luck with that, though, and didn't hose the cylinder head.

I miss that car.

[GasSavers_BEEF]

seing that your car is a 2001, I would get a scangauge and monitor the temp of the engine coolant and you can see MPG in real time.

I don't think that your problems came from hypermiling. I think there were issues with something else.

you could use your techniques with the scan gauge and monitor all of your temps and other vitals and decide for yourself if you feel comfortable doing it. I would have said that hypermiling may have been a problem if it were the trans overheating, but the engine?

it is all about your comfort level so this is just a suggestion. and all the money you have spent trying to save gas probably put a bad taste in your mouth about it too.

[GasSavers_topher]

That's damn good numbers for an EX with that tranny. As far as you head cracking I'd say it had overheated too.

Do you live near sea level?