Overheating M50

[craigieeb]

Right, where to start....................

a while back, I had water coming out the exhaust, so much so that my wastegate was full

so I pulled the head but couldn't see anything obvious, so sent it off for pressure testing and it came back with a clean bill of health,
but the guy said it desperately needed a skim, because it was like a donkeys leg
and it was
so it was done,


it was put all back together and now there is no water coming out the zaust

came to the conclusion that the head could of been "lifting" when I was "on boost"

so gave the ARP's an extra 5 ftlb

but now that's it's all up and running again after some injector issues,
I'v got some serious overheating issues going on,

I was out in it today, didn't get very far until the heater matrix exploded and dumped all the boiling water onto the passenger footwell

popped the bonnet and the top pipe was like a balloon,
cracked open the bleed screw (E36 radiator) and it was just an abundance of air screeching out,

So, me thinking it must of just been the heater matrix letting in air,
I joined the 2 pipes together that go to the matrix,
put it all back together again, bled it, and bled it to the point I know for certain there was no air at all in the system,

Let it sit on idle for a while, and it all looked good,

but by the time i got to the petrol station and back, (under a mile)
opened the bonnet again and the top hose was ballooning once again,

I'v checked the water pump and it still looks brand new, with no play in it at all,

the thermostat is spot on

the Pusher fan is kicking in at 80 degrees

bought a new radiator cap,

I'v had the reservoir off the side of the radiator and i did find what looked like a tiny little crack at the top of it,
but on further inspection, and dumping it in the bath, while blowing into it,
the crack doesn't go all the way through the thickness of the plastic,
so it's not leaking from there,
I'm waiting on a new one turning up just for peace of mind tho,

urm, what else
all the pipes are split free
there is no water dripping from anywhere.
and the gasket is a thick MLS type


when the new radiator arrives and it turns out not to be that..........

anyone got any suggestions ?

[craigieeb]

Yeah, both pipes are hot,

there doesn't seem to be any smell of exhaust gasses, but i suppose i could get a hold of a "sniff tester" from somewhere




just to add.....

there is no oil in the water and no water in the oil....

[rich318i]

sniff test it 100%

blown gasket it sounds like. sniff test will tell ya

thinking back now mate, you have a cracked block 100% on one of the cylinders or the head is

money is on the head

game over

[rich318i]

If it has a small crack between the cyl/cooling, it might not let much water through but will pressurise the radiator. You can use an exhaust gas analyser in the coolant tank (be careful not to let the probe touch the water), or there are test kits like this http://www.ebay.co.uk/itm/SALE-DIY-VEHI ... 1031311271 which indicate the presence of exhaust gases. Any decent workshop will have one of these test kits and some will hire it out if you cant get the car to them for testing.

If you can borrow a hand held infrared temp sensor, you can check across the core of the radiator to see if it is evenly-ish hot. If not, this will point towards it being partially blocked.

The water pump impellor might be suspect.

incomplete bleeding leading to air locks is the main cause of overheating/pressurising the system so you need to be very certain you have got rid of all the air, especially from the heater matrix circuit.

Overheating is not fun..

just standard as his all ready put it and done that. there is is crack 100%

[craigieeb]

sniff test it 100%

blown gasket it sounds like. sniff test will tell ya

thinking back now mate, you have a cracked block 100% on one of the cylinders or the head is

money is on the head

game over

It's not the gasket, it's about 5mm thick steel

and the head has just been pressure tested,

Hate agree but, i'm sort of thinking .............. the block

If it has a small crack between the cyl/cooling, it might not let much water through but will pressurise the radiator. You can use an exhaust gas analyser in the coolant tank (be careful not to let the probe touch the water), or there are test kits like this http://www.ebay.co.uk/itm/SALE-DIY-VEHI ... 1031311271 which indicate the presence of exhaust gases. Any decent workshop will have one of these test kits and some will hire it out if you cant get the car to them for testing.

If you can borrow a hand held infrared temp sensor, you can check across the core of the radiator to see if it is evenly-ish hot. If not, this will point towards it being partially blocked.

The water pump impellor might be suspect.

incomplete bleeding leading to air locks is the main cause of overheating/pressurising the system so you need to be very certain you have got rid of all the air, especially from the heater matrix circuit.

Overheating is not fun..

A cracked block is the way i'm swaying tbh,

The radiator isn't blocked, i had it out and checked it in the bath/ filling emptying etc
and it's evenly hot allover, checked by hand,

The water pump was obviously new at the time of the fresh build, and it still looks factory fresh today

and your right, it's not fun!! it just seems to be 1 thing after another with this car!!

i'v bypassed the matrix due to it exploding and spilling it's guts allover the footwell,

like I say, i'll do a sniff test and see what that uncovers

if it turns out to be the block i'll just simply pull it out and fit another one

[rich318i]

its the head they dont test them up to temp. just for cold leaks

[rich318i]

soild blocks are rare as for a cracks never seen one ever. head 100

[leeparkes]

Id put money on the block.

Magpie has just gone M52 so maybe his old M50 block will be up for grabs?
Good engine too, i sold it him.

[craigieeb]

Yeah, im sort of settled on the idea of changing the engine,

Already been on the phone to Mick
and reserved the 2.5 that was taken out before we slapped in the 2.8


Great times!!!!!!!!!

[magpie]

Id put money on the block.

Magpie has just gone M52 so maybe his old M50 block will be up for grabs?
Good engine too, i sold it him.

see ya soon Craig .

[leeparkes]

Would be interesting to see whats caused it, too much boost??

[craigieeb]

see ya soon Craig .

Sooner than you think,
Stick the kettle on luv

[magpie]

bring ya own biscuits

[craigieeb]

Would be interesting to see whats caused it, too much boost??

Can't say for sure lee,
Could of just been a tired engine ?

Plus giving it a load of boost might of just found it's weak point ...?

Either way, this is the last chance, if there's anymore problems,
It's getting stripped, and im moving on to something else

[rich318i]

did you lower the compression on it for the turbo conversion or did you leave you standard ?

[leeparkes]

It's not the gasket, it's about 5mm thick steel

[balilu91]

i ve had a similar issue with my M42

matrix blowing, overheating, hoses started being blown away, alot of pressure in reservoir and this went on for 2 or 3 weeks

at the same time changing hoses, radiator cap, water pump and it ended up being the radiator. bought a new one and never had any more issues

[craigieeb]

Well, here we go, I found the culprit or should I say culprit...S


Cylinder 3..... click for a bigger picture




and Cylinder 6...... no need to click this one

[E30BeemerLad]

It's the boost innit

[craigieeb]

Dont blame the boost, boost is goood,
engine baaaad!

[magpie]

booohhHH, said the crowd .



re-doing work is a royal pita but on the upside it's character building ........

[rich318i]

swearing !!!

[Rav335uk]

Rebore or new block?

[craigieeb]

I'v got another engine in bit's Rav, the heads fresh from the machine shop with a clean bill of health,
so that'll be getting built up tomorrow and plopped in

[Rav335uk]

Is that Micks old M50?

[craigieeb]

Old is the word, oh wait that's the guy who used to own it

[leeparkes]

Is the second pic a deep gouge?

Im with Lee, i reckon boost caused it, or it was an unoticed imperfection in the bore while it was still NA and would probably run on for years like that with not much trouble, throwing some boost in there has just sped up the process.

[Rav335uk]

LOL, looks like he might need it back

[craigieeb]

Is the second pic a deep gouge?

Im with Lee, i reckon boost caused it, or it was an unoticed imperfection in the bore while it was still NA and would probably run on for years like that with not much trouble, throwing some boost in there has just sped up the process.

it's not a gouge, the crack is the line underneath, and the bit on the top, is where it's either been heating up or the water has been burning off and causing a burnt type water mark


but what I think has caused it is...

the dodgy injectors I got from injectortune making it run lean as hell

LOL, looks like he might need it back

He'll have to pay through the nose for it, I'v spent a fortune on cleaning it

[leeparkes]

it's not a gouge, the crack is the line underneath, and the bit on the top, is where it's either been heating up or the water has been burning off and causing a burnt type water mark

Ah, i see it now.

[craigieeb]

FFS MAN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


The new engine is in, and as you can tell, the cracked cylinder/s was the culprit,

just had it out and it's over heating again,
i only went about a mile again, and the top hose was like a fooking balloon

so whats left to change??
water pump
radiator
and
the 3 water pipes, thermostat housing to radiator, top/bottom and back of waterpump to the block and the bottom of the rad... (bypassed the matrix btw)

what about the cometic headgasket

getting totally p1ssed with this thing now.

[DanThe]

Unless you can be 100% certain the headgasket is sealing that is obviously the first place to be looking

[magpie]

getting totally p1ssed with this thing now.

feeling that