I ran into a 1991 E34 M5 for sale through a friend of mine. I'm realy excited about it, but after lots of reading on this forum I'm approaching the car with caution. I have not seen the car yet, but hope to soon. I understand the the S38 has a great history, but rarity of parts (especially the head) can make the ownership of this car an expensive undertaking. Below is the email from my friend talking about the car.

"I have a friend at work who wants to sell his 1991 M5 Dinan. It has 150K
miles, he had it at one Autocross about 3 years ago (at my urging) and
didn't like that sport. He has been driving it to work as his daily driver
until about 6 mos ago when he got married and they carpool to work in her
car. He has just rebuilt the transmission and had the Dinan
suspension worked on so he could get the factory spec camber into the tires.
He is asking $3000 for the car.

Now the bad news - he thinks there is a blown head gasket. There is a small
oil leak out the front of the head/block joint and the car used about 1 qt
of water every 1000 miles. There is also steam coming out of the dipstick
tube when the engine is warm."

My friend is a mature person and I put alot of trust in him and the guy who has the M5 is a turst worthy sort as well from what I understand of him. Neither would want to pull a fast one on someone. The guy selling the car wants someone to fix it and use it, rather than part it out and is willing to give someone a great deal if it indeed just the head gasket. But what is wrong with the car is their best guess. Do the issues stated in this email sound like a head gasket problem? I'm not sure I'm interested in the car if it is the head itself.

I have never owned a BMW before and always loved the E34. I would love to own an M5 E34 and if this one really only requires a head gasket, it could be my golden ticket.

As I said I have yet to see the car but I do beleave that is is in great shape (other thn the possible head gasket issue). I want to have a couple of opinions before I go see the car and perhaps some guidance on what to look for to varify that it is not something much more serious. I'm already planning on having a compression test done, but what else?

I have done as much research as I could on this forum before posting, so I hope my post isn't too newbie. Thanks for any input.

M5 owners (there are at least 2 logged in as of a few minutes ago) will tell you a lot more, but my impression of the M5 is that you want to stay far, far away from one that needs major work unless you've got the knowledge and money (or just a huge pile of money) to work on it, as they are definitely not cheap projects. 3k sounds like what one without an engine would go for.

A compression test should reveal whether or not it is the headgasket, as compression will be reduced in at least one cylinder, if not eliminated.

Having been through a very very expensive engine rebuild due to a cracked block in my car, i'd be very wary of any M5 that was exhibiting the symptoms above. Doesn't mean I wouldn't buy it, i'd just be going into it with eyes wide open

John

New M5 owner here..so others will have more experience but I will add my opinion to see if it may help.

It is very important to determine if this is indeed a blown head gasket. If it is then you can make a somewhat reasonable estimate on the cost to fix the problem. Compression check would certainly be the first step...maybe check the plugs and see if the car blows steam from the exhaust as well.

A quart pf water per 1K seems like a lot..it is going somewhere (exhaust or into the oil) so check the oil as well. Water in the oil is not good for bearings obviously.

One way of looking at this is 'What is the worst case scenario'? In this case I think it would be a total rebuild or replacement engine, if for instance the block is cracked or there is another problem deeper than the head gasket. At that point you are talking large amounts of money to fix (8-10K I would guess...others will have better numbers) at which point you need to ask if this is worth it. The engine is what makes the M5 so unique and therefore in many ways is the one thing you need to be somewhat sure of.

My personal opinion is that unless you can either confirm that this is a head gasket issue or unless you are prepared to spend money and time to fix the car you should be very careful. Although 3K is cheap money (fair price for a clean car is more like 12-15K) these cars (like many older cars for which parts are expensive) can break your heart if you are not careful. Take it from someone who bought a cheaper Porsche 951...you will pay sooner or later.

Run...run far far away. While you're at it, HIDE.

All of the above apply. If it were me I'd look at the overall condition of the car. Is it beat up? Is the car in excellent condition? Worst case senario you need a rebuild. That is really not such a bad thing if you will be building a engine to go in a great car. If the car is a POS that needs a rebuild I'd run. If you can get a great car that just needs a rebuild for say 2K and you have another 10+ in your wallet it may be a good thing. I'll go out on a limb and say that you could have a great M5 with a NEW motor for 15K. Thats the price of a decent used runner with miles.

Yeah, $3K is scary cheap, which is why I'm nervous and curious at the same time. I got the guys number last night and will probably try to swing by to see it tommarrow. I'm really not looking to do a full rebuild, but if I need to have a head refurbished and a head gasket done I think it would work out rather well. I'm a hands dirty, do it yourself type guy with quiet a few simular tappable friends and I think I can handle everything but the head work (which would have ot be hired out). For me it really comes down to, "Is what they think is wrong, really what's wrong?"

Are head gaskets a weak link in S38s? Is the S38 in the M5 a S38 B36?

Are head gaskets a weak link in S38s? Is the S38 in the M5 a S38 B36?

No and yes since this is a US model.

^^ Agree with MBlasters points. Look at this as if you are buying a chasis alone and then budget downward as if you had to do a complete engine rebuild since with the motor apart you are only going to only want to do it once and the right way.