Too much pressure ?!!
Got a problem with my Brabus G36........
Just had new Merc Rad put in (3months ago)
New Brabus head gasket (3 weeks ago)
New thermostat (last week)
New Top hose (last week)
New pressure cap (last week)
Problem is that when driving i seem to be building up alot of pressure and
now have coollant coming thru top hose it is being forced thru the top hose
as it deffo isn't leaking, the car isn't over heating as temp is sitting around 80-90 deg'.
HELP!!!!!
I'm no expert but it sounds like the system was not properly bled and there may be air bubbles in it....
The rad cap is the thing which controls the pressure. Presumably you changed the original because it was leaking due to "Too much pressure".
I think you have a leak in the top hose somewhere. Is it coming out at the joints?
If you reallly did have too much pressure the cap should blow and release it. Do you have an overflow bottle? Make sure that is only half full of water and it is free to blow off also.
Hi Steve,
Not wanting to be the bearer of bad news but I had a diesel Range Rover P38 that did the exact same thing. I reckoned it was a hairline crack or warp in the cylinder head or block. I got so fustrated with it that I traded it in.
The next guy bought it as a trade sale at a great price.( no warranty)
It lasted a month and then blew the engine.
But then it was a LANDROVER wasn't it!!!
Don't think this has helped really, you just brought back bad memories.
Best of luck.
Steve,
From past experience, check following:
No airlocks,
Hoses fitted correctly, ie fully pushed on and no kinks
Hoseclamps correctly located and fully tightened
Thermostat actually opening also double check that the correct one for your engine was fitted, by verifying part numbers.
Correct pressure rating radiator and/or expansion tank cap(s)
Radiator good and clean
Cooling fan working correctly
Fuel injection system working correctly
No air leaks on intake
Above two meaning severe lean-out will cause extreme heat during combustion and/or pre-ignition
Remeber that a new part can be faulty as well, i.e. 10% of new thermostats stick
If all above OK, then test coolant for combustion gases with dye test
Also consider:
On the six-cylinder engine it is quite a challenge not to damage the gasket during installation, especially when performed with the engine in the vehicle. Why was the gasket changed? If because of overheating, was the source remedied and was the head skimmed and by how much. It is no good taking the part fitter's word for it - speak to the actual person who did the machining. There is so much to think of and so often it is just one little factor which will upset the balance. Even more so with a high performance engine like yours.
Good luck and let us know how you get on
I would sugest you take it for a good run and then to you garage for a CO2 test.
Just make sure that whoever works on it has the brabus technical information. The ECU is bespoke and the radiator cap/thermostat may well be different from standard. Same for timing and valve clearances.
Reference the head - you already had compression ratio 10:1 and 600cc per cylinder. That means anything more than absolutely minimal skim may well take you to 10.5 or 11:1, probably requiring high octane or ECU remap on 95. Easy way to find out would be to do a reading of exhaust gas temperature during a run. Any reputable workshop should be able to do this for you.
Is it true that the brabus head gasket is over £500?
Over £500??!!!!
thats crap - it cost me £465 - :shock: :shock: :shock:
Does that mean i gotta bargin Mercfan???!!!!
Was gonna get one custom made but went the speedy route instead
No, Not my style.
Just reliving some bad memories you reminded me of.
The cooling system presumably with the right mix and a radiator that works efficiently and a hose system with no leaks builds up its own pressure within its system. Normal use over pressure is controlled by the thermostat/ rad cap into the expansion tank. All this has been already said. So, what is emptying your system? Where can the excess pressure be coming from. THE ENGINE, there is nowhere else, faulty or damaged head gasket, maybe not torqued correctly, hairline crack in a block wall, warped head, too much or not enough of a skim taken off the head.
JUST DON'T PANIC
All will work itself out OK in the end. Let us know how you get on.
Best of Irish Luck.
Does that mean i gotta bargin Mercfan???!!!!
Sounds like it - last price was £546, but I wonder if there is need to buy this expensive. Will have a look later at my Elring, etc catalogues :idea:
Shame i didn't ask you sooner!!!
Then again if i need to take the head off again i may need another one.
My G is comin back later today - think my guy has run into a dead end......(GULP)
Steve,
Unfortunately, it doesn't seem like Elring are doing a HG for the 3.6. Neither can I find any other for now, so seems back to square-one for now.
I'd follow the checks outlined above and if you need to do the HG again, make absolutely sure that it gets done by people who KNOW what they are doing! Ideally, it needs 3 people on the job - one either side lowering the head and the 3rd at the front handling the bits'npieces there and directing the two "side-men" whilst lowering the head onto the gasket. Also get hold of a product called "Molyslip Copper Gasket Sealer" It comes in an aerosol can. Spray this liberally on both sides of the gasket before installation. Some engines are just prone to HG failures and I don't like doing the same job twice. This stuff has not ever failed me, even on engines with blatantly warped heads(but not enough metal left for skimming).
Hellooooooo - anyone remember me? (GWOA's reunited!!)
Well it's been along time since i was last here - but after having her in storage (loosing my job and 2 kids later) it's now time to bring her back
jump start and service and she's rockin and rolling apart from this prob.
the pressure seems to build and build - took the cap off of the coolant bottle and it still hissed after not bein turned over for 8 weeks - i have half filled the bottle and took it for a drive for about 10 miles and my light comes on and the coolant has all gone - left it over night massive pressure when i remove the cap - my guy has now gone to work for porsche so i'm at the mercy of high street grease monkeys - HELP!
I had pin hole leak in the little hose that comes from the back of the head into the heater system, this causes air to be constantly taken into the system in the worst hottest place possible. replace this if it is suspect and also check the thermostat housing for leaks or cracks, if it is one of those plastic ones get rid and substitute with a metal one from a 300E.
Hi if the engine has been seriously roasted then block distortion can occur..and there is NO cure other than a new block ..sorry to be a pessimist but you have tried everything else...did the engine "hydraulic lock" at any time due to water in a piston cavity..that can cause the same problem.....
hydraulic lock?
Not sure what this means - one piston cav did have water getting into it hence new H/G
New Block.........awww really? ball park cost?
hi Sreve a hydraulic lock is caused when water leaks into a cylinder and the engine is started . as the piston comes up on the compression stroke it cannot fire because of the water and exerts massive pressure on the water and cylinder head in a very localised area which can distort the head and upper cylinder bore along with bending the connecting rod that the piston is attached to......if not inspected correctly when dismantled for the gasket change..including checking piston dwell at top dead centre and checking the bore for distortion the problem will manifest itself again..which appears to be your problem. A new bare block and the transfer of all parts from your existing engine plus dyno check at final assembly could cost GBP as much as 5000 to 6.000...best to try and source another engine of known pedigree....or an exchange short motor if such a thing exists.....
Hey Steve, don't despair yet - it can be just as well a small little something. Hydraulic "can" cause a block to distort, but the m104 which i believe is what you have, is a different beast alltogether. On them, it will just push the rod through the piston. Check your PM - we'll meet up and check it out - can't be that hard to sort.
MercFan - noted and replied.
i think / hope its just something over looked
Cheers
CS
Hi Steve the block is the same as in the W124 24 valve saloon car....amg put a different crankshaft in to change the stroke... so a block should not be hard to find secondhand -----if required.....
...amg put a different crankshaft in to change the stroke....
but i think his is a brabus conversion, do they also go the crankshaft route, or do they bore out the cylinders to get a 3.6? it's easy to get lost in all the detail....when one sees as many G's as you do in a day!
if its the M104-941 engine AMG put the 350SD crankshaft into it to get increased performance.....
Suggest double checking the radiator for cold spots after a run, yes, you have fitted one only three months ago, but with h/gsk also being replaced shortly after with oil contamination, wondering if radiator has developed a clog, restricting flow.
Check on the rear heater matrix hoses, so that they are not inversely fitted. The hose following from the front of head, running along the off side of the head, should attach to the bottom pipe on the bulk head connection of the heater matrix. Check the vicous coupling.
Regards,
Many thanks to you all - sorry for not saying it sooner - been working in India for over 3 weeks
Yes it is a Brabus conversion, not AMG
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Cheers for all the replies - Tyreman, you just tryin to put the sh1ts up me??!!
The head gasket was changed as oil and water was mixing and water started to get into one of the pistons. the head was taken off and went away to be leak tested it was skimmed but i don't know by how much but am very sure it was minimal.
gonna have it looked at tomorrow so if anyone has any other tips lettuce know
Cheers