BMW E36 328i Head Gasket Fail

[M4RK_F]

Hello.

I own an E36 328i Coupe that’s been off the road for a while due to a blown head gasket. I’m about to have this (and a few other niggles) fixed by an independent BMW specialist.

I was wondering...

Are there any underlying issues that might cause the head gasket to fail?

Am I correct in thinking that the head warps when it gets too hot? If so, is there anything I can do to prevent this happening again?

I’ve seen several E36 328’s advertised for sale with uprated metal water pump impellers. Could (a possibly brittle) original plastic impeller have caused the overheat? And should I replace this?

Is there anything else you’d recommend doing while the engine is opened up?

I appreciate any help or advice those in the know can offer.

Cheers. Mark.

[g3org3y]

Cooling system is considered a weak point on these. As you mention, plastic impeller water pumps can be problematic but I think that was more an issue on the earlier M50 engined 320/325s. Leaking/cracked expansion tanks also potentially an issue. I'd suggest replacing the whole shebang: radiator, waterpump, thermostat/housing, hoses etc.

[M4RK_F]

g3org3y said:

Cooling system is considered a weak point on these. As you mention, plastic impeller water pumps can be problematic but I think that was more an issue on the earlier M50 engined 320/325s. Leaking/cracked expansion tanks also potentially an issue. I'd suggest replacing the whole shebang: radiator, waterpump, thermostat/housing, hoses etc.

I’ll consider that, thanks G3org3y.

I did mention replacing hoses to the garage, but they pointed out that the cost of fixing the head gasket and replacing other parts for piece of mind could easily push the repair costs over the value of the car.

The car needs a few things sorting to get it through the MOT. I’m trying to balance costs against the cars value, but also don’t want a repeat of the head gasket issue in the future.

Is it possible to pressure test the cooling system for leaks?

I’m aware it’s not been used for a while, which may have had a detrimental effect on any rubber components.

[helix402]

The heads and blocks can warp on these engines. No need for a metal impeller pump. Just a new genuine BMW one. Be aware that sometimes the head bolt threads pull out of the blocks on old M52s.

[330ti]

Much easier and cheaper to get a complete good engine .

[helix402]

330ti said:

Much easier and cheaper to get a complete good engine .

Indeed. I know one specialist who refuses to change M52 head gaskets for the aforementioned reason.

[Aark]

helix402 said:

Indeed. I know one specialist who refuses to change M52 head gaskets for the aforementioned reason.

How much do you think a straight engine swap would cost? I’ve been quoted 10 hours labour plus machining the head and any required parts for the head gasket.

I did mention an engine swap but the garage said it would probably work out double the cost.

[Collectingbrass]

M4RK_F said:

g3org3y said:

Cooling system is considered a weak point on these. As you mention, plastic impeller water pumps can be problematic but I think that was more an issue on the earlier M50 engined 320/325s. Leaking/cracked expansion tanks also potentially an issue. I'd suggest replacing the whole shebang: radiator, waterpump, thermostat/housing, hoses etc.

I’ll consider that, thanks G3org3y.

I did mention replacing hoses to the garage, but they pointed out that the cost of fixing the head gasket and replacing other parts for piece of mind could easily push the repair costs over the value of the car.

The car needs a few things sorting to get it through the MOT. I’m trying to balance costs against the cars value, but also don’t want a repeat of the head gasket issue in the future.

Is it possible to pressure test the cooling system for leaks?

I’m aware it’s not been used for a while, which may have had a detrimental effect on any rubber components.

The garage aren't wrong, but if cost is an issue why sort the head gasket? I'd have thought scrap value + head gasket bill would be more than the value of the repaired car as a shed. If you want to keep it that's a different matter, but while I get the sense in doing the cooling system refresh while it's in for the head gasket, its not difficult at all and you could DIY. Doing an E39 took me a short day and it was the first time I'd done it. There's a whole list of really good how to's here : https://www.pelicanparts.com/BMW/techarticles/tech...

[M4RK_F]

Collectingbrass said:

The garage aren't wrong, but if cost is an issue why sort the head gasket? I'd have thought scrap value + head gasket bill would be more than the value of the repaired car as a shed. If you want to keep it that's a different matter, but while I get the sense in doing the cooling system refresh while it's in for the head gasket, its not difficult at all and you could DIY. Doing an E39 took me a short day and it was the first time I'd done it. There's a whole list of really good how to's here : https://www.pelicanparts.com/BMW/techarticles/tech...

Goood points. The Pelican Parts resource is great, thanks for sharing that.

[sparks_E46]

When my old 528i had suspected HG failure I was quoted £600 for an engine with 6 months warranty, and £450 to fit it. Quoted 10 hours if I recall. Reasonably happy to go ahead, but it turned out the creamy substance under the oil filler cap was condensation and I had a duff thermostat. The car is still on the road, and that was nine years ago.

Back then I was advised you don’t repair these blocks, if they’ve been cooked and the damage is done, it’s game over.

[skypeller]

I’m amaZed I didn’t warp the head in my e36 328i back in2009 when the car overheated and I mustn’t have realised for a good 5 miles (driving to hard to keep looking at gauges oops)

The problem turned out to be the plastic impeller on the waterpump wasn’t able to drive under pressurised water system .... if you held the pulley in vice and turned the impeller it would spin with a bit of force..... at a glance though it appeared fine so I thought it was a head gasket for a good ten minutes of nearly crying haha (it couldn’t have been thermostat because the whole system was red hot not just the engine side)

[skypeller]

Just read the last past before mine, yes very common on the 6cyl petrols of this era to have oil cap mayo.... the thermostats fail open nearly every time - genuine ones anyway in my experience

I’ve owned/bought at least 4 BMW’s out of my 12 to date with temps that won’t climb fast enough all sorted by a new thermostat & coolant

[M4RK_F]

Thanks for the replies.

The garage have said they won't be able to fully diagnose the problem until they open the engine up, so I'm waiting for them to get the car on the ramps. Hopefully it'll turn out to be something less than the head, but I'm not hopeful — the car was misfiring and the first diagnosis by the BMW specialist was that it's the head.

In terms of costs, the car is a reasonably decent/straight one I think (I think it's been garaged for most of its life), so I defiantly think it's worth getting back on the road. But this is a second car for me (a toy) and I have a limited budget to get it sorted. I'd love to lavish it with a load of new parts and get it just how I want it, but I can't do that at the moment. Maybe once it's back on the road and I have funds in place, I'll change the cooling system, inlet manifold, steering rack and add a smaller steering wheel. But for now, I'm focusing on sorting out the immediate issues — head gasket, MOT and some body work issues, to get it back on the road.

There are a couple of nice examples here:
https://www.pistonheads.com/classifieds/used-cars/...
https://www.pistonheads.com/classifieds/used-cars/...