Is my engine trashed?

[littledonny]

To make a long story short:

-I own a 1999 Boxster with 75k miles.

-The plastic coolant tank on my car ruptured about 8 miles from my apartment. I filled it with 30% antifreeze and 70% water and got it home as quickly as possible, and the temp was climbing very fast. The hottest the gauge read was a little past the last white tick mark. I'm certain there was no coolant left in the tank when I got it home, and I'd be shocked if there was any circulation at all by the end. Getting up to speed and coasting in cool air did not reduce the gauge temp whatsoever.

-The car then proceeded to be sit at my apartment for a few months, and was towed without my knowledge. It was my fault for not going up to that level of the parking deck to check on it. Shame on me, I know.

-While in the tow yard, the temperature went down to around 5 degrees F. The temp stayed below freezing for 3 days, which is highly unusual for this area of the country.

Harsh judgments aside (I know, I'm a terrible owner,) I now have to decide whether the car is worth the tow and storage bill, which is $4300.

1) What are the chances my engine will be good to go with a new coolant tank? Should I be more concerned with the possibility of an overheat or a deep freeze?

2) If the engine is trashed, what sort of costs am I looking at to replace the engine?

3) If the engine is trashed, about how much is the car worth?

Thanks for your input.

[txhokie4life]

I'll make a guess

$5k-10K to replace the engine (depending on how you choose to do it) -- assuming you need to do it

$2500 with bad engine.

I can't believe the storage bill is $4300! I'm in the wrong business.

m

[zodman]

I don't know what type of coolant you used but some types of coolant will turn the rest of the coolant into a gel that will clog many passages. That might account for why the temp climbed fast. The plastic tank can be easily replaced, and the proper coolant re-added for a small reasonable cost if you had stopped and towed it home or to a repair shop, but I know that's little consolation now. With 70% water and freezing conditions, plus the unknown coolant type, it is real hard to say whether it is salvageable...ice and gel throughout the coolant paths makes for some tough math. The towing companies make their sweet cream from situations like yours....to them it's just a scrap metal find with extra goodies on the inside...made even sweeter when the owner arrives to pay. Later they may even try to attach liens via your local DMV. These guys don't even care if your car was stolen - sometimes even sitting on the car for days before notifying an owner.

I don't know how much leg you have to stand on to fight them on the towing/storage, but I can guarantee by the time the fight is over they'll still be ahead. Bailing the car out now, the engine may be rebuilt, but it will need to be inspected, as well as the passageways for the coolant. Depending on the type and year, they can take up to 6 gallons of Porsche coolant and Distilled water in an exact 50/50 mix. I don't have the confidence knowing what 70% water does in the wind chilled prairies of a Wyoming winter.

I don't have any $ estimates to throw at you, just sharing what I know from dealing with trying to recover stolen cars and winter conditions from the days I lived in cold climates.

I hate to say it, but if you've got $4,300 at hand, I'd put it towards a newer used boxster. But this is only one mans opinion without seeing the car.

[littledonny]

I used Porsche coolant. The coolant passages probably aren't clogged - liquid was literally pouring out on the road behind me. My hope is that means it was bone dry.

Is there any chance the pump ran dry and there was still uncirculating coolant in the bottom of the engine? If so, would the fact that it was so near empty and without pressure that the last little bit of coolant turning to ice wouldn't harm the block?

I'm willing to take my chance on the possible overheat, because I was there when it happened. I don't think I hurt the engine, although I didn't expect it to get that hot that quickly. I'm much more worried about the freezing.

[zodman]

With contraction and expansion, there is a risk of seals rupturing. Quite possible your car had less stress on the engine during the freeze with lower fluids, but at the same time the "lower" spots on the engine may have had more content in them, as ice rises, places for the non-freezing liquid may not have had much more room to travel(imagine a ballon inflating in a box), but my thoughts where also on the other places coolant travels.

If for example, the impeller blades on the water pump broke, and blocked passages to the engine, hot spots could have baked portions of an engine enough to encourage a valve spring failure. I don't recall what the proportion is of oil/coolant but I do remember that my Father taught me that an engine is more dependent on coolant keeping it cool instead of oil. Lower the coolant enough, and a cooked engine is served for dessert.

If you do recover the engine/car, make sure you replace the water pump, and if it's blades are broken, back flush the whole system and replace the oil cooler (and it's seals) as well.

I truly hope you find a workable solution.

[secretagent214]

Just my opinion, but I expect that the car will run fine with a new coolant tank and fresh coolant (and maybe new water pump). It sounds like the car was still running when you parked it so it probably survived the overheating without too much damage. As for the cold, my Boxster is parked outside year round and just experienced some 0 degree weather a few weeks ago without any ill effects. That 70% water/30% coolant mix isn't ideal, but even that has a freezing point around 5 degrees F (at least according to one chart I found on the net).

Edited January 20, 2014 by secretagent214