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Engine ran overheated, lost alot of oil and now no compression

17K views 46 replies 23 participants last post by  Alex323Ci 
#1 ·
I recently bought a 2000 328i from a friend who overheated the car when the accessory belt on the water pump failed. He kept driving the car for several miles with the temp gauge in the red and it eventually lost all power. He had it towed to a shop and they said it needed a head gasket and a new head, quoting him $5000 for the fix.

So he ended up selling the car to me for next to nothing, and I began pulling it apart to see if I could get lucky and just change the head gasket and be good to go.

I believe the car does have a bad head gasket but am worried it might have sustained damage to the bottom end. These are the symptoms I have found so far:

Car was very low on oil, like not even on the dipstick. I drained out about 3 quarts I believe and this was within 1000 miles of an oil change and he is confident it was full of oil before it overheated. It appears to have blown a lot of oil out on the drivers side of the engine but I cant tell from where. The oil has a strange, acrid burnt smell. The oil does not appear milky or have any other signs of coolant in it.

The coolant appears to be full and I can't see any signs of oil in it.

Spark plugs looked flooded with fuel, probably from trying to start it. They may have had a little oil on them.

Compression is way low; I only checked two cylinders but one was only building 40psi and the other maybe 10.

Anyone have any idea if I might get away with just changing the head gasket or does it sound like I have bigger problems?

I have the Bently service manual and am familiar with checking the head bolts to make sure they will take torque and the threads in the block aren't damaged before removing the head.

Any input is appreciated!
 
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#34 ·
OUchies.
 
#39 ·
I didn't clean them, they all look that clean tho.

I still don't understand why I wasnt getting compression on any cylinders when the head gasket looked good everywhere but by number 6 and all the other pistons looked good.

The head isnt obviously warped and looks okay.
 
#43 · (Edited)
fried the rings... But the block wont be obvious you need to check it with a edge.
 
#40 ·
No matter how you want to look at this, the cheapest way to go is a 2k used motor. Anything else will be more interesting and cost more, and I always like the idea that now you would have all these spare parts from the blown motor, (depending on what you'd have to swap onto the new one :) :thumbsup:
 
#41 ·
Once coolant goes into a cylinder. They can do some Great Steam Cleaning...
 
#44 ·
So I'm looking into getting a junkyard engine. I found a short block for a pretty good price, the VIN says its from a 99 328i so that's kosher but the part number on the block is 1436921. The part number on my block is 7502903. Are those two part numbers interchangeable?
 
#45 ·
Well I bit the bullet and bought a (hopefully) good used short block and a head that had been checked out with new valve guides and a valve job. Going to buy the gasket kits and all the other pieces i need and start putting it back together.

The bottom end has 130k on it. Do you guys think it would be worth putting in new main/rod bearings and piston rings or just call it good?
 
#47 ·
before dropping any more time and money into this 328i I would be absolutely certain this car doesn't have a cracked rear subframe. hate to say it but this yr and model is known to have this issue more than others. It's costly so be sure the car is clear or I'd sell it before putting more into it than its worth.
 
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