Head gasket or engine warning e46 content

2002 325xi. About 200k. Recently replaced radiator, hoses, sensors. Worked fine. One day wife driving, drove it until light came on. Ended up replacing the rest of the cooling system. Now it pops the radiator cap. Tech says head gasket. He also says to get used engine as replacing the head gasket won't work. They never hold up. Ideas? Oh and now misfires on 5 and 6 too. Should I start by retorquing the head bolts? What about concerns over block warpage? And I worry with a used engine. Plus even more time to swap than redo head, plus I'll have to do all the little stuff to it that has already been done to this one. Thoughts????

I don't know the DIY E46 head job but if it's like the DIY E36, it might actually be an even proposition with a motor swap time-wise. And maybe money-wise too if the head needs machine shop work and the head bolts aren't re-useable? What's a used M54 motor at 100K? Like, $700?

OTOH, if you can get a used M54 head in good shape for $200 and slap that on with new bolts and gasket, that might be the middle ground. Saves you the down-time because the old head doesn't need to go to the shop in the middle of the job.

W/100k, more like 1500. Or at least that's what I've found.

Here's the big problem with the aluminum block M54. If you overheat it at all, but especially all the way to the red end of the gauge, the head tends to warp and rip the threads for at least one of the head bolts out of the block. Apparently it can be repaired with a kit, but I've also heard this is tricky and requires someone who knows exactly what they're doing. So, short answer, new engine is probably the easiest, cheapest option. If you're curious, have the tech check if the head bolts are loose - if any of them are, the block is probably trashed.

Yes, re-torque the head bolts. This won't fix your issue, it'll just tell you if the head bolt threads have torn out of the block.

Could be simple head gasket, pulled head bolt threads, and/or cracked head. Prepare for the worst.

I bought my 2004 325iT from a customer because it needed a head due to cracks in the valve seats/coolant jacket.

The fix for that is time sert. Like a, helicoil only much better. You do it on all mag case 911s when you replace head studs. BMW guys say you do it on all bolts no matter. The bolts are stretch bolts so the all need replacement if removed

NEALSMO wrote: Yes, re-torque the head bolts. This won't fix your issue, it'll just tell you if the head bolt threads have torn out of the block. Could be simple head gasket, pulled head bolt threads, and/or cracked head. Prepare for the worst. I bought my 2004 325iT from a customer because it needed a head due to cracks in the valve seats/coolant jacket.

And here I thought the I6 was the way to go

markwemple wrote: Tech says head gasket. He also says to get used engine as replacing the head gasket won't work.

If you have to ask a tech, take his advice. :) What he would do himself vs what he recommends for you may be different. A lot (most?) service customers are going to be entitled / irate if they assume costs to teardown and then the engine isn't fixable. A good-running M54 swap is the cheapest way out...because of labor.

If you can do the work yourself, tear it down. Check the head and block for square, and other issues, determine which way to go.

markwemple wrote: And here I thought the I6 was the way to go

It is! The V8s are a whole 'nother magnitude of crazy.

That said, it's the older iron block engines that really built the reputation. My 535i has 340k on the original, never-opened engine and cooling system (aside from fluids, hoses and belts of course)...

Yes, it crossed my mind last night to ask: is a 200k E46 worth spending any more money on? I haven't heard of many with that kind of mileage, and I'm not sure BMW engineered them to last. Transmissions, diffs, bearings, rings, bushings, dampers, AC evap and heater cores, P/S pumps and wiper motors, oh my.

In reply to The 01 330i I just picked up w/209k still pulls strong. Fortunately the cooling system was recently rebuilt too. It definitely has things to address, but it runs & drives way better than I expected.

That's only one additional data point though.

JBasham wrote: Yes, it crossed my mind last night to ask: is a 200k E46 worth spending any more money on? I haven't heard of many with that kind of mileage, and I'm not sure BMW engineered them to last. Transmissions, diffs, bearings, rings, bushings, dampers, AC evap and heater cores, P/S pumps and wiper motors, oh my.

Bushings and dampers are any car nearing 200k. Even a Corolla will have worn bushings and weak shocks at that point! Never heard of diff issues, rings, P/S pump, wiper motor or heater core issues on the E46 either, and I'm a former owner. Bearing issues are specific to the M3 and that is an extremely exotic engine. AC evap and auto transmissions, well, every car has its downfalls.

The core engine/manual trans drivetrain is solid and reliable but it is a maintenance-heavy car. The more maintenance is deferred, the more the value of the car dips below the cost to fix it properly. And when you get to the third, fourth or fifth owner you are usually dealing with people who just want a cheap luxury car and throw maintenance to the wind. That is why most give up before they make it to 200k.

Wow. I've seen really nice 10-year old BMW's with head gasket issues for really cheap. I always thought they'd be great fix and flip opportunities. Glad to be reading this now....

If it were a iron block, then HG no question. Also, I've seen too many threads with cracked heads. I think I'll go the engine route, but just get an engine with a little higher mileage. I've put a lot of $$ into this lately and I'd hate to give up on her.

pointofdeparture wrote:

JBasham wrote: Yes, it crossed my mind last night to ask: is a 200k E46 worth spending any more money on? I haven't heard of many with that kind of mileage, and I'm not sure BMW engineered them to last. Transmissions, diffs, bearings, rings, bushings, dampers, AC evap and heater cores, P/S pumps and wiper motors, oh my.

Bushings and dampers are any car nearing 200k. Even a Corolla will have worn bushings and weak shocks at that point! Never heard of diff issues, rings, P/S pump, wiper motor or heater core issues on the E46 either, and I'm a former owner. Bearing issues are specific to the M3 and that is an extremely exotic engine. AC evap and auto transmissions, well, every car has its downfalls. The core engine/manual trans drivetrain is solid and reliable but it is a maintenance-heavy car. The more maintenance is deferred, the more the value of the car dips below the cost to fix it properly. And when you get to the third, fourth or fifth owner you are usually dealing with people who just want a cheap luxury car and throw maintenance to the wind. That is why most give up before they make it to 200k.

It's good to hear they still make them like they used to. I'm a big fan of the series and the E46 is the only iteration of the 3 I haven't owned yet.

With enthusiast DIY care, an E46 will go damn near forever. But unlike the Koreans and Japanese, the Germans don't know how to make the cheap plastic and rubber stuff last.

If you keep an M54 lubricated and cool, service it regularly, and don't drive it like a mee-maw, it will last a LONG time. It's the rubber and plastic stuff that fails, unlike a Corolla which is made of 85% plastic and will go forever.

If the Germans would contract out to Japanese rubber suppliers, they'd be unstoppable.

A highly-respected BMW pro tech over on Bimmerforums posits that a modern BMW needs about $3k worth of maintenance per year (that's labor-inclusive, so less if you DIY). If that maintenance isn't done, it accrues, so if you buy a car that's been neglected for three years, figure on $9k worth of work to make it right. His assessment tends to match my experience.

My wife has a 2006 325ix that she insists on having professionally maintained, and I think that $3k figure is about right for the modern cars.

I buy mine with the 4 year BMW warranty, then slap on their aftermarket warranty for another 5 years after that. USAA sells that extended warranty, same company Assurant Solutions, same coverage, for less than half the dealer price. Then I have a one-owner car with nine years of service records to sell out of the back of Roundel. In theory, at least, since I haven't sold a car since 1996. Good thing I live on a corner lot because I need all the parking spaces.

02Pilot wrote: A highly-respected BMW pro tech over on Bimmerforums posits that a modern BMW needs about $3k worth of maintenance per year (that's labor-inclusive, so less if you DIY). If that maintenance isn't done, it accrues, so if you buy a car that's been neglected for three years, figure on $9k worth of work to make it right. His assessment tends to match my experience.

Not all BMWs are the same, and where does he draw the line for "modern?" Just a swag based on my experience -- $600 a year if you DIY.

If it's an aluminum block, replace the engine because the machine work to make the studs stay in the block is finicky and very expensive.

If it's a cast iron block - just do the head gasket and deck/refresh the head.

Tyler H wrote: With enthusiast DIY care, an E46 will go damn near forever. But unlike the Koreans and Japanese, the Germans don't know how to make the cheap plastic and rubber stuff last.

The Japanese automakers haven't figured that out yet, either.

I got nothing more to add other than the only E46 that I personally dealt with that had a bad head gasket was jetting the coolant externally on the intake side by cylinders 5 and 6. Customer scrapped the car after paying the labor charge to disassemble to that point (intake removal, mainly) so I never found out if it pulled a head bolt or whatever.

I've had to do Timesert style repairs on a few Subaru blocks where some garage hero overtorqued the head bolts. The procedure is there for a reason...

For whatever it's worth, Baum Tools currently has the thread repair jig/tools on sale right now for $408.38. B115000 plus TS1015 and TS10155 in a package deal.

Sounds like more voted for entire engine.

markwemple wrote: Sounds like more voted for entire engine.

If you just REALLY want an iron block, the early E46 323s still came with the M52. Following that logic, it MAY be possible to put in a M52B28 out of a later E36 328? From what I understand, those engines have a lot left on the table to get them pretty close to E36M3 output.

In reply to Tyler H:

What about the magnesium block engines?

I don't see why one should add a ton of weight when they could be removing it instead.