removing the m30b35 head tommorow for a headgasket change

[BigKriss]

I've got a metal rule, new head bolts and new head gasket set. I don't want to machine the cylinder head flat as it was done around 40,000kms ago, (don't want to spend the money) but i will if it's warped, becasue it has over heated quite a few times (10+ times in the last 2 years). i'm losing coolant and I don't know where from. I've replaced the fan clutch and thermostat with no luck. a recent blown headgasket check and a leak in the coolant system at 1 bar did not reveal anything.

any comments appreciated before i do this job. robin535's recent thread on the job was informative so was George M's comments in the same thread.

!

[Robin-535im]

I've got a metal rule, new head bolts and new head gasket set. I don't want to machine the cylinder head flat as it was done around 40,000kms ago, (don't want to spend the money) but i will if it's warped, becasue it has over heated quite a few times (10+ times in the last 2 years). i'm losing coolant and I don't know where from. I've replaced the fan clutch and thermostat with no luck. a recent blown headgasket check and a leak in the coolant system at 1 bar did not reveal anything.

any comments appreciated before i do this job. robin535's recent thread on the job was informative so was George M's comments in the same thread.

!

I'm by no means an expert but here are the mistakes I recently made...

1) Try to locate the cam gear with respect to the head before you loosen the timing chain, making sure of course that the O/T mark on the big pulley and the line on the block are lined up. I thought I could just mark which chain link went with which tooth, but then the chain slipped off the lower gear when I was rotating the bottom end to and fro to get the pistons to the top for cleaning. Luckily the cam was still in the same position so I could go back and make alignment marks from the cam to the head.

2) After you drain the coolant from the radiator, actually do what Bentley's says and drain it from the block too. I thought the one would be good enough, but when you break the seal all the coolant in the head pours into your cylinders and oil passages, not to mention across the garage floor and out onto the driveway.

3) Before you do anything in the engine, pull it up on ramps and take off the metal heat shields that block access to the header bolts. Take the 4, 12mm (deep socket) copper nuts off the down pipes... do a 1/4 turn tighter first to break the seal then back them off. Then take the car off the ramps so you can get to the head without a step stool. The step in Bentley's where it says to disconnect the exhaust is after the engine is already out of commission, so I couldn't get easy access to the copper exhaust nuts and had to pull them from above, not an easy thing to do!

Otherwise the steps in the manual were pretty much all there was to it. I left the intake on and took the exhaust off, but still needed to separate the downpipes from the headers to get the head to come off with ease. And you read the whole saga about how to lift the head. Not real heavy but awkward, and not much leverage leaning over a fender.

HTH

- Robin

[Martin in Bellevue]

You intend to check the head for plane with a 'metal rule'?

Why not replace all the coolant lines & flush the system to determine the health of the coolant system before removing the head? Is there a board member nearby who's done a head gasket job on an m30?

[BigKriss]

Yes, i'll check it for straightness with a metal rule. is that okay? or not accurate enough?

i actually didn't touch the head today, i replaced the main coolant hoses and added some new coolant and flushed the radiator. the radiator is fine and looks new. In the last month i've changed the thermostat, fan clutch, almost all coolant lines and if it plays up again, then i'm going to change to the headgasket. I've read most of the posts on here about doing the headgasket. I'm worried about not being able to lift it out with my dad, i'm pretty weak guys. even the radiator was a slight struggle. to get out and put back in.

There are no board members that can help me with the job.

Robin, thanks for your comments also.

You intend to check the head for plane with a 'metal rule'?

Why not replace all the coolant lines & flush the system to determine the health of the coolant system before removing the head? Is there a board member nearby who's done a head gasket job on an m30?

[BigKriss]

One other thing, when i replaced the heater pump and heater valves, over 1 year ago now i was smelling coolant inside the cabin, should i be worried that the heater core is ****ed also? i can't see and seepage on the garage floor, there are no leaks.

[The Bigfella]

I pulled the M5 engine apart at a workshop owned by a couple of mates who are diesel mechanics. The straightedge that they use is about 5mm thick. They scoffed at me when I said I would check another head with a steel rule - apparently if they bend, you have no accuracy.

Good luck with the rebuild - I'm waiting on my M5 bits from BMA. Then I'll think about building the second engine at some stage.

[BigKriss]

thanks, my 2ft one bends.

I pulled the M5 engine apart at a workshop owned by a couple of mates who are diesel mechanics. The straightedge that they use is about 5mm thick. They scoffed at me when I said I would check another head with a steel rule - apparently if they bend, you have no accuracy.

Good luck with the rebuild - I'm waiting on my M5 bits from BMA. Then I'll think about building the second engine at some stage.

[The Bigfella]

I've got a metre steel rule here (which bends) but I might try it out and see how it compares.

[genphreak]

Kriss, are you sure its not a leak elsewhere? Steam can escape unnoticed and gradually take the coolant down- over 1000km a litre or two is nothing.

I'll help you but am flat out at present, working weekends and days- I just can't get a break immediately. I may get a break sometime soon- but it'd only be on a weekend. I also know the right place to get the head machined/valve guides/seats done if it needs it. It won't be a problem getting it off as Robin says, you and I can do it for sure (if we have to), remember the wooden brace idea. Best to pop the bonnet off and get in there being really careful with the timing chain and a scribe. I will defiantely come by to help you lift it if you can get her ready. We could check it out, and if it needs to goto the shop I can drop it there on the way home. I'll pick it up and come back and help you fit it, but the car won't be in commissison until we're done and its finsihed so that will be a minimum of 2 weeks with me unable to come and help you all the way through... sorry bud. Can you stage the job a little?

[BigKriss]

I will see how the car holds up Nick, if it starts to overheat again, then I will start on it the following day.