When is it safe to purchase a car with a blown head gasket? I looked at a V70 a few days ago. The guy talked till he finally said it would not start. I assumed that meant they drove it until it destroyed the motor. I have never done a head gasket job but figure that will be a good way to get a great deal on a clean car. I'm guessing that it would be almost safe if it starts up, what do you guys think?

 

all you have is his word that it's the head gasket that's keeping it from running. Generally, a blown head gasket will NOT keep a car from running - it'll just run like home fried butthole. Run, dont walk, away....The best way to learn how to do head gaskets is to buy a honda civic...They blow all the time, and they're simple to replace.

 

Figure in your offer the worst-case-scenario of replacing the whole engine.

 

Well, I have never done a head gasket and have not read through the sticky yet but I do understands the signs: water in the oil, oil in the coolant, steam (white smoke) out the tail pipe when it's running... My fear is that the owner drove it and let it overheat which would destroy the motor or at least warp the head.

I do NOT want to replace a motor and I have seen a couple priced low enough to junk and move on, like $600. So I can get a tow around here for $54. I do have some time to waste but really don't want to.

Is there a way to prevent a bad head gasket or is it something every car is doomed to experience? I have never had one yet and I have had cars with over 400,000 miles on them. What causes the head gasket to go bad?

 

As far as preventing head gasket damage and avoiding replacing it -

I have heard some cars (like the Civic reference above) spoken of as having more prevalent HG problems. I do not know how much of that is true. I do know that (generally-speaking) a car should not have any HG problems if it is not overheated and if it is properly maintained with regular coolant changes (with the appropriate coolant that helps preserve the integrity of the HG). If your car is overheated, never (ever ever ever) refill it with cool water/coolant until it is stone cold. When a super-hot car is refilled immediately with cool fluid, it cools too fast and can cause the head to warp (especially if aluminum), thus rendering the HG "insufficient" and causing it not to seal well. Not overheating a car and coolant maintenance are the main things I have always heard of to keep your HG happy and healthy. While there may be some makes/models more prone to HG problems, and there may be an occasional lemon HG or incorrect factory installation out there, folks routinely run cars with the original HG until the engine needs rebuilding if this is followed.

I did not think the 850 HG was that bad of a job myself. It took a while, there were many steps, and it must be done precisely, but it did not seem nearly as bad as a mechanic or two said it would be ("You've never done a HG and the first one you're going to do is on a VOLVO?!? GOOD LUCK!")

 

I purchased my '96 850R wagon last year with a blown headgasket. The car was CHEAP, but overall good condition. It did run, so I was able to drive it onto a trailer to get it home 200 miles. I spent one Saturday pulling the head, took it to a machine shop and had it milled, etc., and then the following Saturday reinstalling the head, and then doing a FULL stage 0 at the same time. Over 1 year later, and about 7,000 miles, and not a manual transmission swap a month ago, it's doing great! So, all in all, if the overall car is in good condition, the car is cheap, and you feel comfortable with your mechanical ability, and you are prepared for the "unexpected" to be wrong with it, I say go for it. I do all of my own work (besides machine work) so I can do just about anything as long as I have the tools.

Good luck!

 

So, if I look at a car with a blown head gasket, I can assume the car has already overheated and count on a warped head?

 

My car was overheated. It got so it it melted the spark plug wires. It's running great now.

 

well its best to have it machined anyway to be sure it has a good seal... but if the pistons and stuff are gone.. forget about it..

I'd do a compression test if the car turns over.. if it has good compression.. how bad could it be?

 

With used cars, if it won't turn over, or the seller won't let you turn it over, assume you need an exchange engine.
The ONLY time it's safe to buy a car with a blown head gasket is if it's happened in the last week before it's sale and no one has tried to start it.
If engines with blown gaskets sit, the coolant seeps into the bores and down into the bottom end, doing considerable damage. If the engine is run with coolant in the oil for any significant time, then left to sit, the coolant actually combines with some chemicals in engine oil and attacks bearing overlay materials.
Not only that, but you don't know if someone tried to start the engine with a cylinder full of coolant and bent a rod or more.
So, only buy assuming you know you need to more than likely buy another engine, if you don't, bonus for you, but assume you will have to.
Of course, if the engine still runs and you can assume it's a blown head gasket, do your sums and decide whether you want the work or not, and it WILL be a lot of work, if you intend to keep the car and do the job properly.

 

I've seen several for sale lately. I also purchased one for a few parts and it sat a little while before the new owner got around to doing the gasket and by the time he tried to start it the motor was locked up. I think the pistons rusted to the block.

I didn't realize a blown head gasket could do so much damage.