BMW E39 540i Head Gasket Failure ?!!?
Discussion
My 540i has been dropping it’s coolant level recently despite a relatively new cooling system. I put the car into a local garage we trust (use for our Jensen) and they have diagnosed this as the head gasket failing. They said that they had done a test which showed exhaust gasses in the coolant which was forcing it to leak out. These cars aren’t notorious for head gasket issues so I just wanted to get some opinions before I dropped £1.6k- 1.8k on the repair. (I must have spent at least 5k on maintenance this year). It’s worth pointing out that the car seemed to be driving ok before, got up to some serious speeds no problem -car has 66k miles on it. Cheers guys
I was looking closely at 540i e39's earlier this year and understood HGF to be fairly common on that engine. I may be wrong, but it's the impression I came away with. Largely due to weak cooling system bits ala most other BMW of that era. Porous heads can be an issue too of the engine overheats.
HG don't generally partially fail they either work or they don't. It may be the way you've worded the HGF as " failing".
I'd be doing it properly if the car is a keeper, don't want that HGF-bodge-in-a-bottle stuff ending up where it shouldn't. That said I'd want to be doubly sure it is HGF and not just a coolant leak before dropping those kind of notes on a replacement head gasket.
HG don't generally partially fail they either work or they don't. It may be the way you've worded the HGF as " failing".
I'd be doing it properly if the car is a keeper, don't want that HGF-bodge-in-a-bottle stuff ending up where it shouldn't. That said I'd want to be doubly sure it is HGF and not just a coolant leak before dropping those kind of notes on a replacement head gasket.
The cooling systems on the V8's run at high pressure to keep the coolant liquid as the engines run at 110 degrees to cut exhaust emissions.
It's more likely to be some plastic component (e.g. heater valve) that is giving up, leaking and hard to spot. Have you run an onboard diagnostic check to check for this as mine reported a problem? It's also worth the £400 to convert to Evans Waterless Coolant- replaces the H2O with glycol which has a higher boiling point and therefore less pressure on the cooling system.
It's more likely to be some plastic component (e.g. heater valve) that is giving up, leaking and hard to spot. Have you run an onboard diagnostic check to check for this as mine reported a problem? It's also worth the £400 to convert to Evans Waterless Coolant- replaces the H2O with glycol which has a higher boiling point and therefore less pressure on the cooling system.
If there's exhaust gas in the coolant then it's pretty much borked. They run mega hot (110+ degrees) on part throttle for emissions and they're basically cooked alive until something goes pop. There are cooler thermostats available to make them run at a sensible temp, around 80-90 deg.
Steel Seal is much better than K Seal that doesn't really work anyway. The problem with doing the head gaskets is that really, it's an engine out job. The chances are, the bloke threads will be knackered and if the block faces need skimming, that's a strip down. With it in bits it would be madness not to replace the timing chains and guides as they are another common M62 weakness caused again by running so hot.
Steel Seal is much better than K Seal that doesn't really work anyway. The problem with doing the head gaskets is that really, it's an engine out job. The chances are, the bloke threads will be knackered and if the block faces need skimming, that's a strip down. With it in bits it would be madness not to replace the timing chains and guides as they are another common M62 weakness caused again by running so hot.
66k seems a bit on the low side for it to be suffering from head gasket issues, I've had several V8 e39's, all with over 150k, they all used a drop of coolant without showing any signs of head gasket failure, you say you trust the garage but I think I would want a second opinion. Also, I wouldn't use the steel seal stuff as I've had personal experience of using it only to end up with a blocked heater matrix.
Edited by njw1 on Wednesday 28th November 19:29
bmwmike said:
I was looking closely at 540i e39's earlier this year and understood HGF to be fairly common on that engine. I may be wrong, but it's the impression I came away with.
From what I could gather the M62 v8 certainly isn't immune to head gasket failure but it seems to be a lot more common in the L322 Range Rovers fitted with the M62 than it is on the e39 for some reason.
Stick Legs said:
Steel seal is a bodge.
I know someone who is very knowledgable on these engines and 'cheap' as he has a hobby rather than a business per-se.
PM me if you are interested in his opinion as it will be a lot less than £1800!
It is a bodge - but a very good one. The early version of it they brought out wasnt great and caused lots of other problems like congealing with certain types of coolant or blocking coolant passages. The version out now works really well as long as u follow instructions. I’ve used it once on an old engine that could barely run and wasn’t worth the expense of engine strip down and it worked perfect. I also know of plenty of people who have used it without problems - the internet tells U otherwise tho. I know someone who is very knowledgable on these engines and 'cheap' as he has a hobby rather than a business per-se.
PM me if you are interested in his opinion as it will be a lot less than £1800!
You have to weigh up what an old 540i auto is worth and fix it accordingly. It's so easy to be balls deep into a car like this with big bills coming thick and fast. Today the head gaskets, tomorrow the automatic gearbox. Where do you draw the line? It's very easy to say 'they're great cars, spend the money' when it's not your car and not your money.
I'd Steel Seal it and run it for as long as you can, but I've always been sensible and pragmatic with cars.
I'd Steel Seal it and run it for as long as you can, but I've always been sensible and pragmatic with cars.
Hi Guys, sorry for the delay in replying- pistonheads keeps putting up new member bans.
Have decided to take the plunge and repair it (replace the head gasket), probably a terrible decision lol.
I thought about using stop leak, but I still hope that this will be a long term car for me and so wanted to repair it properly.
The person who one day buys it off me will be the luckiest person ever as at this rate the car will be virtually rebuilt !
Thanks for all the advice anyways!
Have decided to take the plunge and repair it (replace the head gasket), probably a terrible decision lol.
I thought about using stop leak, but I still hope that this will be a long term car for me and so wanted to repair it properly.
The person who one day buys it off me will be the luckiest person ever as at this rate the car will be virtually rebuilt !
Thanks for all the advice anyways!
If you haven't replaced the S shaped hose that runs from block to heater matrix yet then do it at the same time. It's failed on two of my M62 v8s.
When I bought my 535i I changed rad cap, wp, thermostat, matrix hose and expansion tank, (all with behr or BMW parts) as I knew that these were the parts most likely to let me down. The original water pump had lots of play at 90k miles.
When I bought my 535i I changed rad cap, wp, thermostat, matrix hose and expansion tank, (all with behr or BMW parts) as I knew that these were the parts most likely to let me down. The original water pump had lots of play at 90k miles.
Just as a thought, m62s are known to leak coolant from the valley pan under the intake manifold so may be worth checking that first..
Have a look on this page, he mentions it part way down
http://www.meeknet.co.uk/e31/BMW_M60_M62_M62TU_Eng...
Have a look on this page, he mentions it part way down
http://www.meeknet.co.uk/e31/BMW_M60_M62_M62TU_Eng...
Edited by e28525e on Wednesday 5th December 08:06
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