Author Topic: Engine Trouble! (Read 2808 times)

Chinoskii · « **on:** October 30, 2012, 03:26:44 AM »

Hey guys i'm new to this forum. I have a '91 318ic. I've been having some issues with my coolant getting into my oil. The car is misfiring bad and it take a good bit to start up and it's almost impossible in the mornings. It also blows white smoke(which is coolant from what i know) until it reaches operating temp. I suspect it's a bad head gasket and pray nothing is cracked or warped. I wanted to know if anybody had done this project before and what their approach to it was whether or not you machined the head, or rebuilt the whole engine instead of the top end, etc. All help is GREATLY appreciated

keflaman · « **Reply #1 on:** October 30, 2012, 06:48:43 AM »

Welcome to the forum.

You have water in the oil AND it's blowing white smoke UNTIL it gets to operating temperature? :eek:

I think a blown headgasket would be the best scenario you could hope for and you are definitely going to need to have the head checked for cracks and straightness. If you continue to drive it you risk hydro-locking the motor and that's expensive.

Based on my experience and situation, I pulled my motor to reseal all the oil leaks and found my crank thrust bearing worn beyond limits. I decided to refresh the motor and bought another engine to install so I could drive the car. In the meantime, I've slowly accumulated all the parts and consumables I will need at some pretty good prices.

Will you be doing the work yourself? How many miles are on the car and what kind of shape is it in? Is it your daily driver?

YMMV, but HTH.

DesktopDave · « **Reply #2 on:** October 30, 2012, 09:49:03 AM »

I'm not sure where you are with mechanical skills, space, time, a spare car, tools, etc. So I'd suggest taking it to your local independent import/foreign car mechanic and having him take a look at it. He can run a compression, leakdown and exhaust gas test to determine what the problem is.

I'd assume from your description that you have a blown head gasket at the minimum. If you keep running the car you're only going to cause more damage. Coolant in the oil will contaminate the main bearings and waste the motor in very few miles if you run it that way. If it's just a head gasket, that's not all that expensive nor difficult with a decent selection of tools. If it's a cracked head, I'd be calling salvage yards to see what they had available.

Keep in mind that later e36 motors will also fit, and they have upgraded parts that make them slightly more desirable. Any used motor you consider must have decent compression numbers and very little crank end-play. I'd also consider a new clutch and refreshed drive-line parts while this was being done if you intend to keep the car.

bmwman91 · « **Reply #3 on:** October 30, 2012, 10:58:18 AM »

As others have said, the best-case scenario is a blown head gasket. The M42 head is known for cracking between the exhaust ports for cylinder #2, and you would not be the first victim of that either.

As Dave recommended, take it to a shop where they can do some diagnostics. It should not be too expensive. You may be able to save yourself some money by doing the labor to remove the head and replace whatever needs it. I believe that the crack that typically forms in the M42 head can be welded, but you definitely want professional help there.

You should refresh the timing chain assembly while you are at it. It is an area full of old parts that often cause lots of trouble. Just make sure to get a 5mm longer top bolt for the driver's side guide rail (specified in realOEM) since the new guide needs it (or you will strip the threads in the head and the bolt will wear through the cover!).

Chinoskii · « **Reply #4 on:** October 30, 2012, 05:56:27 PM »

Alright as for the mileage it's about 125,000. The clutch, water pump, thermostat, front and rear main seals, starter and fan clutch were replaced recently. I'm pretty decent with mechanics but my issue is not really having somewhere to work all the time. This car is my DD but the nly other vehicle i have is my motorcycle and it's starting to get all rainy and chilly up here in WA. I plan on changing up all guides for the chain and the chain itself( thanks for the bolt tip by the way). I've heard that machining the head will cause compression to rise and start blowing oil by the piston rings therefre i should also rebuild the bottom end. Can I get a second opinion on this?

DesktopDave · « **Reply #5 on:** October 30, 2012, 07:14:22 PM »

Sounds like your car is a good bet for an overhaul instead of selling it off. See what the mechanic says & plan your purchases accordingly.

How recently was the water pump and thermostat done? If it's only been a little while since they were installed I'd be double-checking them to be sure they're all kosher. It's unlikely but a bad thermostat could have been the cause of all this trouble.

Cleaning up the head shouldn't change the compression ratio very much. If you're really worried about that you can get a thicker gasket from BMW or aftermarket gaskets like this one. New head bolts too, of course.

Chinoskii · « **Reply #6 on:** October 31, 2012, 12:02:33 AM »

Yea I definitely don't wanna part with the car. My dad's had it for years and he gave it to me as a high school graduation gift. All those things were replaced about a year ago, the fan clutch is a few months old. I just want to have everything in place before i start the project so I won't have to stop and wait for parts/money. I've even contemplated buying a spare engine and rebuilding it. I'm just trying to have my car basically showroom clean. Not really a whole racing thing. Just a few aesthetics here and there. But I'll look up a euro shop around here and see what they say. Anybody know of any reputable ones in this area?