97 Z3 US Spec Engine Questions...

[Geputten]

Hi All.

Help!
We have a '97 1.9L (M44) Z3 here in the US that had overheating issues that I remedied with a new radiator, thermostat, fan switch, hoses and belts. Overheated a lot with my wife not noticing until steam rising. Took the car to a local shop to do a leak-down test and all was ok. Wife took the car on a trip, a 100 miles in and the gauge pegged hot and car died immediately (according to her). Towed it to my previous shop and all cylinders maxed at 40-50 psi. Catastrophic gasket failure? Stretched head bolts?
The shop recommended looking for a used engine, but this one only has 100K miles and everything was just fine before the issue. Besides, everything I'm finding is well over 100K.
Shop said that BMW's can't be rebuilt due to the head bolts rip out the threads....

Ok, here's what I have for questions:

1. Timesert inserts. Can they be applied to the block while engine is in the car or do I have to pull the engine? Has anyone out there done this successfully?

2. Regarding used engines... Mine has the California spec electric Air Pump. Can a non-air pump be retrofitted to my car by transferring over the pump components? Or is the application structural?

Like I said, I prefer to just fix what's broken. I've done a dozen or so head gaskets in my time, but never a BMW. Not sure why head bolts stress out the block so drastically...

Thanks in advance. Happy Motoring.

 

[Andyboy]

The block will be fine.

It's just blown the head gasket. M44's all have iron blocks - it's the alloy block stuff (post 1998 sixes) that have thread dramas.

The head will be banana shaped and may well be cracked from an exhaust valve seat to the waterways. If so, it's scrap. A skim and pressure test will save a warped head if not too far gone. ALWAYS have the front timing cover fitted and flush to the top head surface when skimming.

Use a genuine BMW head gasket or at least a known good brand like Elring, the thicker one they supply when the head's been skimmed. New head bolts of course plus a gasket set with all the gaskets, seals etc.

An M44 is an M44. All US E36 318i and 318iS cars plus the 318Ti Compact use that engine. They made hundreds of thousands so a good used one is easy to find.

The previous M42 (89-95) had a steel coolant pipe stub on the back of the head. The M44 uses a plastic one and you MUST fit a new one. They do become brittle, they do break and they do lose a lot of coolant very quickly when they do.

 

[Mike Fishwick]

All you need to replace the air pump is a blanking plate to seal the cylinder head jount - but why bother, unless the control valve is jammed, and the rubber hose is melted?

 

[Geputten]

All you need to replace the air pump is a blanking plate to seal the cylinder head jount - but why bother, unless the control valve is jammed, and the rubber hose is melted?

The drama from the repair shop stating the head bolts will strip out led me to searching for a replacement engine. No air-pump specific engines are available (at a reasonable cost) in my area. As I mentioned, I'd rather have my low mileage engine fixed as opposed to replacement.

 

[Geputten]

The block will be fine.

It's just blown the head gasket......

Thank you Andyboy. I'm making an appointment with an Import specialist to see what they say. The shop that I was at is good, but do not have alot of experience with German cars.

 

[Andyboy]

The M44 is simple enough.

I did a head swap on a 1995 M42 318Ti with a workshop manual having never done one before.

 

[Geputten]

I talked to the guy that looked at the engine. Former import tech, I guess. He said the only way all the cylinders dropped that low (40 - 60 psi) was that it overheated so bad that it scorched the cyl walls.
I'm gonna pull the head and see for myself.... I really don't want to end up with a junkyard engine......

 

[Andyboy]

Maybe it’s been cooked.

I really wouldn’t get worked up over M44 engines. The bare engine is the same on all cars 95-2000. It’s a day’s work to fit one.

 

[Geputten]

Update: I have the head at a local machine shop to check for cracks/warpage. Head gasket did not look compromised, but a fair amount of oil around the upper oil canals (or whatever they're called - at a loss right now). The cyl walls look perfect. There was oil in the intake manifold in all chambers. I'm going to pour oil into the cylinders to see if it'll seep down. More will be revealed....