M52 head gasket - repair cost?

[gjm 3258]

Let's assume the head needs facing, so factor that in. What else would, or might, need sorting?

And what would the overall bill be, both for a DIY and a reputable specialist to sort it? (I'd phone a couple of specialists and ask, but this time on a Saturday night it's unlikely to be a productive exercise.)

Guesstimates welcome. Just looking for a quick, rough, ballpark figure.

[BMRBOI 8]

I done one on my m50 a while ago. Head gasket kit was 300odd then head studs 100 odd. Skimmed and pressure tested was at mates rate at 150 then torx sockets and custom cam locking tool. Then you need to find out why it happened, so new water pump, thermostat and radiator flush maybe another 200, oil, coolant, filters etc another 100-200. And it might be cheaper to buy from pelican parts.

Now that's providing you are confident and know how to do this. Workshop manual is a huge benefit for torquing bolts etc.

In my opinion, if it's done hi Kms on the engine it might be a better option just to replace the engine. Wouldn't be to much difference in price, providing the new engine is in good condition.

Edited December 8, 2013 by BMRBOI

[antil33t 90]

I'm told the M52's block threads for the studs can rip out when they are being re-torqued as it's made from aluminium. especially if it has been overheated.

I would be looking for a whole M52B28 and just throwing that in with new oil seals and replacement parts.

[gjm 3258]

I done one on my m50 a while ago. Head gasket kit was 300odd then head studs 100 odd. Skimmed and pressure tested was at mates rate at 150 then torx sockets and custom cam locking tool. Then you need to find out why it happened, so new water pump, thermostat and radiator flush maybe another 200, oil, coolant, filters etc another 100-200. And it might be cheaper to buy from pelican parts.

Now that's providing you are confident and know how to do this. Workshop manual is a huge benefit for torquing bolts etc.

In my opinion, if it's done hi Kms on the engine it might be a better option just to replace the engine. Wouldn't be to much difference in price, providing the new engine is in good condition.

I've confidence in my ability, and even though it would take me several times longer than any specialist, I'm happy the outcome would be good.

I'm told the M52's block threads for the studs can rip out when they are being re-torqued as it's made from aluminium. especially if it has been overheated.

I would be looking for a whole M52B28 and just throwing that in with new oil seals and replacement parts.

Yup - ally blocks are generally known for this. The bolts are steel, so there is always the opportunity for problems. Throw in some overheating and there is a real chance of problems.

If substituting a M52B28 for a M52B25, will the 2.5 engine electrics etc bolt up and work, or would I need all the 2.8 electrics and so on, too?

[thorburn 121]

It isn't the end of the world if you wreck the thread. Most people helicoil or threadsert them
Can rent you the cam tool for cheap

[Allanw 1071]

There is a time-sert kit for these engines. Avoid the spring styles, like helicoil - if they expand on the way out next time , you can write off the block. The correct timesert kit comes with a full set of guides etc, but isn't cheap.

If I were doing it, I'd put in inserts anyway - you don't know they're stripping until it's too late (often the final torque setting ).

Also - it's pretty hard to fit the inserts with the block in the car - the firewall/bulkhead makes for difficult access (depending on what chassis), and you DON'T want them in crooked (seen that once already!). You may be able to tilt the block far enough though.

[gjm 3258]

If substituting a M52B28 for a M52B25, will the 2.5 engine electrics etc bolt up and work, or would I need all the 2.8 electrics and so on, too?

I've spoken to a man who knows about these things, and he assures me that the two engines are electrically and electronically compatible. So, remove 2.5, junk it, and replace with 2.8 is a possibility.

I've never tried this on an E36, or any BMW post-E21. Oh, boy...

[*Glenn* 854]

Some of the plugs will be different and you'll find that the B28 will be a Siemens DME and the B25 will possibly be Bosch. If the B28 has ASC and the B25 doesn't you'll have to get a non ASC throttle body and DME. It really depends on what the mixture will be. You also have to factor in the gearbox type as well, auto or manual

[gjm 3258]

Some of the plugs will be different and you'll find that the B28 will be a Siemens DME and the B25 will possibly be Bosch. If the B28 has ASC and the B25 doesn't you'll have to get a non ASC throttle body and DME. It really depends on what the mixture will be. You also have to factor in the gearbox type as well, auto or manual

Thanks Glenn. It's far from a done deal, but the donor car is a nice one, 'right' spec (for us) and reasonably priced... Just has this teensy ickle engine issue where water is finding it's way into the combustion chambers.

[yng_750 247]

Thanks Glenn. It's far from a done deal, but the donor car is a nice one, 'right' spec (for us) and reasonably priced... Just has this teensy ickle engine issue where water is finding it's way into the combustion chambers.

drain the water... job done

[*Glenn* 854]

drain the water... job done

???? Really ???

[gjm 3258]

drain the water... job done

???? Really ???

Made me smile.

Something along the lines of a punctured tyre only be flat at the bottom, so just turn it over.

She'll be a'right.

[*Glenn* 854]

It tipifies alot af the advice given on here by people that really don't have the experience or knowledge to help. But I'll just shut up now.. because I'll assume it was directed to try and help the OP

[yng_750 247]

he said he was confident in his ability so i thought it was fairly safe to be a smartass.

i find it interesting about the threads stripping out, is this common occurrence or is it one of those once in a blue moon things

[gjm 3258]

he said he was confident in his ability so i thought it was fairly safe to be a smartass.

i find it interesting about the threads stripping out, is this common occurrence or is it one of those once in a blue moon things

I did a double-take when I saw your comment, checked how many posts you made and assumed you were kidding. No worries.

I've read several accounts of threads in ally blocks stripping out, although it doesn't seem to happen in all cases. I've worked on Porsche 928s (and other ally block engines) and while it isn't unheard of for a thread to strip, it has been unusual. I've no idea if it is more common with the BMW blocks (perhaps a different thread rate is used?), or if it is a case of a few examples having been well-reported.

[*Glenn* 854]

i find it interesting about the threads stripping out, is this common occurrence or is it one of those once in a blue moon things

I think these sorts of problems will only get worse with the European manufacturers using recycled aluminium & plastic. We are on the 4th & fifth generation of the recycling cycle of these materials and the longevity of these materials is getting less. Look at Yamaha plastic components & alloy castings and then look at the sh*t european manufactureres present us with... not just BMW ... all of the Euro producers. Alloy & plastic components are now failing after 3-4 years

[yng_750 247]

i assume bmw is still subject to the regulations on how much recycled material they use?

maybe they should start selling an optional extra at the factory that upgrades all the plastic cooling system crap with alloy.

or at least making it standard on M cars