So this happened today :(

[hotwire 352]

Thanks Brent.

Lets hope this is the case.

I will do a compression test on Monday.

Compression test will probably not reveal, you need to do a leak down test.

[zero 1160]

did you replace the torque converter? dont think you could ever properly flush that, so probably coming from there.

It was drained and flushed with new trans oil. The trans oil appears clean.

How can oil get from the torque converter to the cooling system?

[KwS 2372]

ah, didnt click that it was the cooling system that was still sludging. nevermind then. Ill learn to read properly one day

I dont recall, but did you remove and flush the radiator and back flush the heater core?

[zero 1160]

ah, didnt click that it was the cooling system that was still sludging. nevermind then. Ill learn to read properly one day

I dont recall, but did you remove and flush the radiator and back flush the heater core?

Yea I removed every single part of the cooling system except the heater core and cleaned them all.

The heater core was flushed in the car cause it was too much of a mission to remove.

[gjm 3191]

It really doesn't take much water to make and oil look sad. You can find emulsion under an oil filler cap on a cold morning on some cars, where condensation has built up enough to mix with a little oil.

Presumably the underside of the oil filler cap is just showing oil, particularly immediately after a drive?

[zero 1160]

So, another update and I'm 99% sure I have engine oil leaking into the cooling system.

I'm 99% sure that its not trans oil, so this is a new problem from when the car initially overheated.

I've been washing out the radiator every day and by the next day it has milkshake in the expansion tank.

There looks like a bit of milkshake on the dipstick and the car is using oil.

The only two places I could think of oil and water mixing is a damaged head gasket, or a damaged engine oil cooler.

I took the oil filter out as its housing is connected to the oil cooler, and the oil in the housing is clean so I don't think that is it.

Is there any other area on the engine where the oil and water could be mixing apart from the head gasket?

[gjm 3191]

There's other places it could happen, but it's extremely unlikely.
Sounds like you have the two main culprits under suspicion.

[zero 1160]

[M3AN 4015]

Oh dear.

[Ahmedsinc 414]

I know I'm to the only one thinking it....who's gonna be the first to say it?

Tough break Nathan, as much as I think you're insanely optimistic going to all that effort to save a horrible little N46 I always root for the underdog! Bad luck dude

[zero 1160]

I have a reconditioned head to swap over anyway as the valve stem seals were shot on my one.

This just brings this swap forward.

I'm just hoping its the head gasket and not something else.

[Olaf 3235]

bummer dude. it's not like caramel is your favourite milkshake flavour, either.

[BM WORLD 1258]

got a oil cooler here if you want to try it

, they do fail often

[zero 1160]

got a oil cooler here if you want to try it

, they do fail often

Thanks Brent.

It got a new oil cooler a couple of years ago, and I don't think that is where the leak is coming from.

But I appreciate your generous offer.

[Ahmedsinc 414]

I have a reconditioned head to swap over anyway as the valve stem seals were shot on my one.

This just brings this swap forward.

I'm just hoping its the head gasket and not something else.

If it is the HG you'll need to get the block deck surface checked for straightness and probably have the head bolt threads helicoiled. The ali blocks tend to have the bolts pulled out of them when they overheat, if it has moved I'd be scrapping it and replacing with an engine known not to have baked itself - the overhaul costs aren't cheap mate

[zero 1160]

Yes, if the block is toast it will be binned.

[zero 1160]

So planning on swapping the head over and doing the gasket on Easter weekend.

When I swap my reconditioned head over with the old one, should I be replacing items 2 and 3;

http://www.realoem.com/bmw/enUS/showparts?id=EX52-EUR-03-2004-E46-BMW-318i&diagId=11_3189

I've heard they can break because they are plastic?

[gjm 3191]

So planning on swapping the head over and doing the gasket on Easter weekend.

When I swap my reconditioned head over with the old one, should I be replacing items 2 and 3;

http://www.realoem.com/bmw/enUS/showparts?id=EX52-EUR-03-2004-E46-BMW-318i&diagId=11_3189

I've heard they can break because they are plastic?

Yes.

Imagine if you got it all back together and the following week...

About $100 worth, at a guess?

[hybrid 1039]

s54 conversion time

[gjm 3191]

s54 conversion time

S62.

[zero 1160]

I will check the head bolts haven't stripped out of the block, by seeing if I can tighten them to torque spec.

If they wont tighten then its a waste of time swapping the heads, and the engine will get pulled and scrapped.

I would absolutely love a s62, or even an m62b44, but I just don't have the money or the knowledge.

Maybe get a bank loan and send it to Ray.

What is more likely would be to swap in the m54b25 and box from my parts car.

Its a shame to go to the hassle of doing an engine swap (plus cert I think), and then only put in a 2.5L six.

All this doesn't matter if the block on the n46 is ok, as I already have the full gasket set including new bolts from a while ago.

The engine already has had new water pump, ccv and hoses, radiator, sump gasket, fuel filter, oil cooler, seals and hoses done in the last two years so hopefully its not for nothing.

[Allanw 1051]

IF the block is flat, get the block "time-sert"ed before trying to pull a head onto it.

Time-Serts are like helicoils, but not crap.

[zero 1160]

IF the block is flat, get the block "time-sert"ed before trying to pull a head onto it.

Time-Serts are like helicoils, but not crap.

So, I shouldn't do the torque wrench test on the old bolts first?

Is time-sert ing expensive, and does the block have to be sent away to be done?

[Allanw 1051]

You can try to torque the old ones, but it's not quite the same.

Alloy blocks change shape quite a lot too My mate is an engine machinist, and he's seen blown headgaskets, just from the liners (either cast inserts, or full alloy blocks) moving down, relative to the head bolts. He's had some shops say they tested the threads, then had them pull when the torqued the head anywyay.

You have to be able to drill straight down, into the holes - you can't do that on some models (like E39 5's).

[*Glenn* 854]

The problem with these late model alloy blocks is that they have little structural strength and the little they have does not like overheating. They often twist and damage the main bearings which lead to oil pressure loss and big end failure. If you ever strip one of these late model blocks they have brackets to support the sidewalls of the block to the main bearing caps. Guys using these late model engines for racing make up a cage that goes into the block followed by the sump