Blown head gasket? Opinions please!

[old-man-andy]

Hi All

2008 F650GS 30k miles

The last 400 miles has seen my usual 63-67mpg drop to 57-59mpg despite pretty much unchanged riding speeds, roads etc.

Tyre pressures checked and are okay.

As the bike's at 30k and due a service, I thought I'd have a look at the air filter to see how dirty it was and whether there were any blockages etc.

Took the air filter out which was fine, but found some water and rusty sludge in the air filter box, concentrated around the location of the engine breather hose connection. The rusty sludge was a gunky slightly oily sludge. The breather hose also had the same sludge in it, as did inside the top of the cam cover where the breather hose connects. The breather hose also had definite droplets of water in it.

The coolant level was "normal" (midway up/down the header bottle) as was the coolant colour (ie decent blue colour).

Is this the symptom of blowing head gasket or just me riding like a Granny (apologies to any grannies out there) causing emulsification of the oil the oil?

Also noticed that the fuel computer has been going bonkers over the same time period - at 70mph under light load it reads 65 to 70mpg (as per normal) but if I open the throttle the readout drops to 48 to 52 mpg (normally never lower than 58 mpg).

Any ideas? (other than take it to dealer for diagnostic)

Cheers

Andy

 

[v8legend]

I found water in mine when I changed the filter for a K&N. I think it's fairly normal. Yours does sound dirty though.

Have you checked the oil? If you haven't got water in your oil, or oil in your water, then there's probably not much to worry about head gasket wise.

As for increased consumption. There could be loads of reasons. How does she feel (ooh er missus)? Has the performance dropped off? Have you picked up any dodgy fuel? I had a similar experience recently after filling up. I ran the tank 10 miles past zero, and all was fine when I filled with quality fuel.

Are you getting your consumption figures from the computer, or are you actually checking it your self. Your problem could be sensor related.

 

[Sooty09]

A bit of gunk in the air box is quite normal.
Check the oil dip stick, if there is a milky white substance on the top of the stick there is a good chance water is entering the engine.
If the oil looks normal and the water level is constant you have probably not blown the head gasket.
Are your brakes free. Sticking pads will do just as you describe. Go for a normal ride and feel for excess heat in the disks.

 

[Dave Ett]

How many miles has it done / do you do?

If it's not many and not often, then condensation will form when the bike cools, and you'll get that oily watery sludgey stuff.

 

[Silversurfer]

The sludge, especially if it is in the rocker box and looks a bit like "white mayonaisse" is usually a sign of an engine not getting up to temperature either from doing mainly short runs or often from an engine thermostat stuck in the open position. The "mayonaisse" forms when water condensation forms within the engine, usually the rocker box, and mixes with the oil. It will end up within the air filter box via the engine breather system as all the engine gasses are supposed to be re-circulated through the engine to cut emissions. An increase in fuel consumption will result from an engine running too cold, although yours does not sound too bad. My normal consumption is around 65/70 mpg (F800GS), but pulling hard at 80 on the motorway does drop it down to around 48mpg. If the air filter is as choked up as you describe the engine will not be able to breathe properly, a bit like running with a choke on, and that will increase fuel consumption.

I would definitely check on the engine temperature as a first check. I think if you had a blown head gasket you would, as others have mentioned, notice either water in the oil or oil in the water and most likely white smoke, (steam) from the exhaust all the time and not just at start-up.

 

[old-man-andy]

Thanks for your replies, chaps.

I found water in mine when I changed the filter for a K&N. I think it's fairly normal. Yours does sound dirty though.

Have you checked the oil? If you haven't got water in your oil, or oil in your water, then there's probably not much to worry about head gasket wise.

As for increased consumption. There could be loads of reasons. How does she feel (ooh er missus)? Has the performance dropped off? Have you picked up any dodgy fuel? I had a similar experience recently after filling up. I ran the tank 10 miles past zero, and all was fine when I filled with quality fuel.

Are you getting your consumption figures from the computer, or are you actually checking it your self. Your problem could be sensor related.

V8 - No oil in water and no water in oil. Thankfully. Dodgy fuel is a possibility. Fuel consumption figures are anally calculated and put in a spreadsheet (how sad) and tally with the OBC average mpg figure. What was weird was when riding at a steady 70 mph, the instantaneous mpg figure dropped steadily from around 68 to 48 mpg and then steadily rose again to 68 mpg. It did this fall/rise continuously over a 100 mile ride back up the M5 from Devon.

A bit of gunk in the air box is quite normal.
Check the oil dip stick, if there is a milky white substance on the top of the stick there is a good chance water is entering the engine.
If the oil looks normal and the water level is constant you have probably not blown the head gasket.
Are your brakes free. Sticking pads will do just as you describe. Go for a normal ride and feel for excess heat in the disks.

Sooty - oil dipstick is fine, nice and oily, no "mayonnaise"/emulsion. Brakes are fine and free too.

How many miles has it done / do you do?

If it's not many and not often, then condensation will form when the bike cools, and you'll get that oily watery sludgey stuff.

Dave - I commute 5 days a week covering 200 miles and do 8000-9000 miles per year. Rides are rarely less than 20 miles, so I was surprised to find the sludge there.

The sludge, especially if it is in the rocker box and looks a bit like "white mayonaisse" is usually a sign of an engine not getting up to temperature either from doing mainly short runs or often from an engine thermostat stuck in the open position. The "mayonaisse" forms when water condensation forms within the engine, usually the rocker box, and mixes with the oil. It will end up within the air filter box via the engine breather system as all the engine gasses are supposed to be re-circulated through the engine to cut emissions. An increase in fuel consumption will result from an engine running too cold, although yours does not sound too bad. My normal consumption is around 65/70 mpg (F800GS), but pulling hard at 80 on the motorway does drop it down to around 48mpg. If the air filter is as choked up as you describe the engine will not be able to breathe properly, a bit like running with a choke on, and that will increase fuel consumption.

I would definitely check on the engine temperature as a first check. I think if you had a blown head gasket you would, as others have mentioned, notice either water in the oil or oil in the water and most likely white smoke, (steam) from the exhaust all the time and not just at start-up.

Silversurfer - I had a BMW 528 that got "mayonnaise" in the cam cover/oil filler cap as a result of 3 mile commutes in heavy traffic (lazy period in my life). A decent run would clear it. So as I said to Dave, I was surprised to see the sludge. The bike's temp gauge suggests that the temp is completely normal. The air filter wasn't that choked - I've seen a lot worse.

On the balance of the evidence, my head gasket would appear to be intact , the source of the rust staining of the "mayonnaise" is a mystery , as is the computer readout, although today it seemed more like normal. I'll keep an eye on it and hopefully it was just some dodgy fuel.

Cheers

Andy

 

[Dave Ett]

In which case, the only possible answer is sunspot activity. Sorry.

 

[v8legend]

A further thought. Check out response 43 in the following thread.

http://www.ukgser.com/forums/showthread.php?t=297565&page=3