Blown Head Gasket

[hgray14]

I am pretty good with cars but when I last dealt with a blown head gasket I had my mechanic take care of it (it was on my 1972 Datsun 240z and was about 20 years ago).

Here is my situation:

I keep seeing 850s and 850 turbos in my area for sale for dirt cheap because of a blown head gasket and I want to know how to go about checking them out. Although I have yet to do it, I am not affraid to change a head gasket.

What causes a blown head gasket?

Once blown, other than over-heating due to a loss of coolant and an eventual head warping, what other damage can be caused by driving around with a blown head gasket?

Once a head gasket is blown, what about that would keep the car from starting?

Sorry if this sounds dumb but is there a way to test compression while a head gasket is blown? I assume not, but figured I would ask.

Obviously, if you run the car out of coolant you can seize the engine up, which would stop it from even turning over when you try to start it, right? But if you don't run out of coolant and you don't over heat the car is there any other part of the blown head gasket situation that would stop it from starting?

Here is my assumption:

If I go to check out a car and it won't even turn over even though it has power then there is something majorly wrong, right?

But what if I go to check out a car and it turns over but won't start and they are claiming 'head gasket'? What would stop it from starting if it is cranking over...other than sitting around for a long time and things of that nature. If they blew the head gasket yesterday is there anything other then a seized engine that would stop it from starting?

Is there any way to figure out if the head is warped before pulling it? And if it is warped what does it usually cost to have fixed; or is that one of the those things you buy new or grap from the junk yard instead of redoing the warped one?

How hard/time consuming is replacing a head gasket? I have a driveway and tools and have done just about everything to my 850s except transmission work and engine rebuilds. I have replaced axles, sway bar, exhaust systems, etc. I am even going to attempt to replace a steering rack, although I have been told it is a nightmare if you can't get your car really high up off the ground.

I have a code reader and am quite comfortable with the 93-95 OBD-I systems; are there codes I should look for that will help me determine if a car is a any good or is a complete waste?

Thanks for any help/advice you can give me. I have saved quite a few 850s from the junkyard so far and would love to save these 'head-gasket' ones if it is just a matter of these owners not wanting to pay the big bucks to have someone else do it.

(A trick my mechanic showed me with my Zcar was to drive around with the radiator cap unpressurized. Since I live in a mild climate I didn't really need to pressure to keep the coolant from boiling at a lower temperature and by running it unpressurized it kept the pressure from forcing extra water through the blown head gasket which would lead to always having to full my radiator. Not sure if this is wise or not but I was poor and ran it that way for three years and not only didn't end up with a warped head but didn't end up having to replace my coolant all that often. Everyone told me I was crazy to drive a car with a blown head gasket but none of them could give me a good reason once I took 'over heating' off the table...but then again, you guys seem to know a lot more than most people so I figured I would throw that out there in case someone has some education for me.)

[Fudge_Brownie]

Lack of compression from the blown headgasket could prevent it from starting. But I don't think this is common when dealing with simple overheating problems. One way to test if the headgasket is blown is to check the oil for coolant and vice versa. I believe they sell kits to test for this too.

[hgray14]

Lack of compression from the blown headgasket could prevent it from starting. But I don't think this is common when dealing with simple overheating problems. One way to test if the headgasket is blown is to check the oil for coolant and vice versa. I believe they sell kits to test for this too.

Thanks, I will check into that. If there were a kit that allow for a definitive answer to if the headgasket is blown that would surely be helpful.

Once I confirm that is what it is then what do I do?

And if I confirm that is not the problem with the car what else could it be that would cause a non-mechanical car owner to think that? Assuming that they called their mechanic, explained the symptoms and their mechanic said, "prolly yur hidgasquet", what else could be a problem that would cause similar symptoms (other than just a simple overheating due to low coolant)?

thanks

Houston

[Jippi 855 GLT]

my 850 HG blew because the heater core went and coolant dumped into the interior and my dad left the car on in the yard and forgot about it. my moms 99 s70 138k i bought it from the original owner and it was caused by lack of maintenance and a bad heater core. i say def check on the heater core. best way to tell is check the carpet..

[Black Betty]

Yes there is a die you can put in the coolant to detect exhaust gases in the coolant.

When buying a car you know to need major work make sure to buy it for the least you can part it out or sell it for. What I mean is say a simple HG job turns into a melted piston. Make sure you buy the car for what you can part it for. The hardest part of the HG should be making sure all the bolts come out easy.

Theres no real way to tell if the head is warped without taking it off. When I talked to Justin (chilledman) he gave the advice that any car over 100k should get a new/rebuilt head when doing the job.

[hgray14]

Cool, thank you all for your advice.

These cars are selling for a little bit more than parts value (around $1K) unless I want to keep them in my driveway forever selling every last part. But for that price, if everything else seems okay, I think the risk is worth it. I didn't realize a compression test could be done even though an HG is blown (although it isn't as accurate). That is good to know.

Is that die better than doing a leakdown test? I saw that Harbor Freight was selling a tester for $30 during their current sale. Before you starting hatin' on Harbor Freight, I have already heard it all but have had great luck with their stuff so far and have never had a problem returning what didn't work.

[FCP Euro]

Black Betty is right. If you are going to try and tackle a head gasket job, don't pay more then around 800 dollars for the car. Also, try to find one that has the lowest mileage so that when you do get it running again, it will last a long time.

[Jippi 855 GLT]

lets do some math, my moms 99 s70 base, the car was offered on the ads for a 1000 i got there to look at it the owner said off the bat that he will give it to me for 500. i fixed the pcv on it and then realized it was the HG replaced the HG on it and drove it for a good 5 miles then the bottom end gave out, ended up getting an na motor from the yard for 600. 500 for the car + 600 for the motor + 300 wasted on HG attempt + 500 in timing belt and tune up parts + 200 on misc mod parts= 2100 in total. i woulda parted it but by the time i got pissed at it already too much blood equity invested into it.. so if you want to flip the car and make a profit on it i would just throw a motor into it and call it a day. the state of NJ also told me that the car was worth 6000 so we owed taxes on the damn thing but i sent them the pics and receipts and they said O... :lol:

[hgray14]

lets do some math, my moms 99 s70 base, the car was offered on the ads for a 1000 i got there to look at it the owner said off the bat that he will give it to me for 500. i fixed the pcv on it and then realized it was the HG replaced the HG on it and drove it for a good 5 miles then the bottom end gave out, ended up getting an na motor from the yard for 600. 500 for the car + 600 for the motor + 300 wasted on HG attempt + 500 in timing belt and tune up parts + 200 on misc mod parts= 2100 in total. i woulda parted it but by the time i got pissed at it already too much blood equity invested into it.. so if you want to flip the car and make a profit on it i would just throw a motor into it and call it a day. the state of NJ also told me that the car was worth 6000 so we owed taxes on the damn thing but i sent them the pics and receipts and they said O...

That is a good thing to remember, regarding the taxes. In the People's Gaypublic of Drugifornia they don't even tell you what the transfer/sales taxes are based off of. They just give you an amount and since it usually isn't too bad on '90s vehicles (usually under $200 and mostly under $100) we don't even bother to fight it. I am going find out how to get a variance since there is no reason for me to pay anything over the minimum on cars that were on their way to the junk yard.

Luckily, I am not looking to do pure "flips". I have a lot of friends and family who after seeing what I was able to find for dirt cheap, all want the results of my next project. So basically, I will be buying on their behalf and getting it up and running for them. They all know that there might be hidden expenses but these are people who were about to run out and buy a 10-15 year old Saturn (or the like) for upwards of $5K. When they see that I am driving around in full-size Swedish luxury with my leather seats, power everything, sunroof, decent gas mileage and in the case of the turbos, quite a bit of power and for less than $2K-$3K they want in. When they learn that these things are starting to push the high mileage limits of the 240s (with proper oil and tranny fluid changes - those 240s don't seem to care how crappy you treat them) and they have an incredible safety record they are surprise they aren't already driving one. I saw an Associate Press article a while back about the old 80's diesel mercedes and how great it was as a used car because reasons X, Y and Z. When I compared all their reasons to the 850, the 850 beat the mercedes hands down and not only is 10 years younger, 10 years more stylish and has 10 years less wear on things like the interior but unlike a diesel, ours are much easier to work on and since so many were produced parts are not only readily available but are inexpensive, relatively speaking.

Anyways, there I go ranting about 850s again; probably preaching to the choir.

Thanks again for all your suggestions.

Houston

[wheelsup]

NAPA makes a test kit that runs around $50 and is good for 10 tests IIRC. Then you can re-buy the fluid for fairly cheap to refill. You run the car and put the tester in the overflow tank, it sucks in fumes and turns a different color if there are hydrocarbons in it (fancy way of saying exhaust fumes).

I've looked at doing what you are doing, however I have not been successful. The reason being every car I've looked at that had a bad HG also was sorely lacking on routine mx and even general mx. The cars were driven hard and rough, interiors were crap and they needed a lot of other work to be reliable cars.

850's are good cars but only if they had been taken care of in the past.

At some point you're going to be better off buying a cream puff w/ low miles, knowing what you know now with how to take care of it, and treating it well. For example there are still 850's around that have 60k-90k on them, they typically sell at dealers (who get them at auctions) for around $4k. I would prefer to go that route and take care of it the rest of its life vs a potential POS car that needs pretty much everything replaced one at a time, if you are going to keep it another 5+ years.

My aunt has a 95 850 w/ 85k on it, garaged during the day and evening, maintained every 3k at the DEALERSHIP w/ records. That is the kind of car you want to buy to keep long term. My $0.02.

I'm sure it can be done but the question remains, how much do you want to d!ck with the car? Is it worth your time to chase something every week or two? Also if the car was driven any length of time w/ that bad HG you're looking at the engine running with coolant in it - not the *best* lubricant.