bmwe21.net forums

Hi guys! This will be my first ever initial post to the E21 forum, so please bear with me if I make any 'noob' mistakes.

I just became a proud owner of a '79 BMW 320i E21 this week. I am located in Mt. Vernon, WA and purchased the car via Craigslist. I have yet to take a photo of the car since I just got it this week (pics will be uploaded soon). The car is a light yellow color, 4 speed manual, and has minimal rust. It's a project car nonetheless.

Okay so here's what I am asking of the forum and the main reason I am posting in the technical section...

The seller indicated that the M10 engine has a blown head gasket. I inspected the oil cap and found 'milky' oil which was a clear indication that the head gasket was broken and that coolant or water has been seeping in. The car however started up with a simple turn of the key. I turned it off within a minute or two of listening to the engine for any noises that could indicate any hidden damage. A few squeaks here and there but nothing too alarming in my opinion. Then again, I am not a mechanic. The seller had a spare M10 engine he purchased that he planned on using to take parts off of to rebuild the existing engine. It was sitting exposed to the elements next to his garage so I don't know how great the spare engine is.

My question to all the experts on here is how difficult is it to replace the head gasket in the M10? What tools am I going to need and further more, what gasket(s) do you suggest and where can I acquire said gasket(s) for online for a great price but still have a quality trustworthy part?

Any links are graciously appreciated. I am eager to get this head gasket fixed so that I can having a running project car. I plan on restoring the car completely (engine, exterior, interior, etc.)

I am probably going to have A LOT of questions to ask you guys as I move along with this head gasket replacement.

Thank you in advance!

Also, how do I tell what M10 engine I have? ... 320i 2.0 or 320i 1.8? Your help is graciously appreciated!

And again for another question, what engine oil should I run? Full Synthetic 10w40?

Welcome here and congrats on a car we hope that's up & running again soon! A few pics are always welcome and may help establish what engine type is in there, the last 7 digits from the VIN may help as well but always a risk there as you never know if the original engine is still in there.

It can sometimes be hard to establish if the head gasket is blown in the first place. Usually they start and run fine when cold, and start to develop overheating or performance issues while warming up. You can always do some tests first to make sure, like check the spark plugs for color differences, do a compression test, check if the cooling system is also polluted or if there's NOx in the cooling system. Sludge in the oil system can also be caused by many short drives or long storage but if there's a chance the head gasket isn't blown I'm sure the seller would not offer it as having a blown head gasket.

Head gaskets usually are not that much of a problem on M10 engines, most cases the head survives and then it will be better to rebuild the current engine. Remove the head and have it tested, you may just be able to reuse it without too much. Head gaskets are complete kits usually, make sure to replace the valve stem seals (usually included in the kit) and head bolts, give the valves a good grind in their seats. It goes a bit too far to write down a complete instruction (if anyone else wants to, be my guest, most welcome!) but I suggest you get yourself a decent repair manual and just take it step by step. Apart from the work on the valves (grinding en replacing seals) there isn't much specialist work included. perhaps a local garage can help you out and you can do the rest yourself without too much hassle or special tools. One Saturday for removal and one for refitting should be way more than enough!

You may find a lot of useful info in our FAQ section and our Top Tech Topics & search function might also prevent you from asking the usual questions

Hi, welcome and congrats on the e21 indeed!! Beeing a '79 is should ave the 1.8, but if early, 2.0 is possible. Like Jeroen says, you can feed the vin at BMWfans.info in the decoder. The other way is look up the number that is stamped in the block itselve.

Looking forward to lots of pics!