Help!! I think i've cooked the cylinder head.

[bikerider]

I know i'm going to get loads of stick for this but here goes anyway. My bongo's a 96 2.5lt diesel and a couple of weeks ago i noticed low level in the coolant tank. I topped it up but then a few days later its low again so i've been checking & topping up on a daily basis till I can get it checked out & repaired. Now here's the daft bit, whilst rushing to get going I topped the tank up then left the cap on the leisure battery 10 minutes down the road i remembered it and stopped. it had only just got to temp but under pressure it had emptied the tank so refilled with water i had with me then because i was stuck on the motorway hard shoulder set off again keeping a sharp eye on the temp gauge but before i could get to the next exit the engine packed in. It sounded like its running 2 or 3 cylinders very roughly and little power. The temp gauge never moved from its 11oclock position and the coolant tank still had the water at full level so before i take the head off I just wanted to make sure that the engine has actually suffered a air lock when the coolant tank emptied. Any advice would be welcome.

Cheers
paul.

[bigdaddycain]

It doesn't sound very good i must admit... I'm afraid it sounds a bit more terminal than a simple airlock... Sorry.

If it's any use, i've left the cap off before now, but i managed 120 or so miles before i saw steam, luckily no lasting harm was done, except for my pride!

It might be worth getting a sniffer test done on the coolant before ripping the head off... you never know

[bikerider]

I would of thought just topping the coolant tank up should of been ok since I noticed it spilling out of the tank after only traveling 10 miles or so from cold. What exactly is a sniffer test? Does it detect oil in the water?

[Northern Bongolow]

pm sent, and aranged to have a look as he is local.

[321Away]

sniffer detects combustion gases if they're present in the cooling system, personally i put not a great deal of faith it!! dont pull the head off just yet, could be other reasons for your symptoms
Julian

[mikeonb4c]

sniffer detects combustion gases if they're present in the cooling system, personally i put not a great deal of faith it!! dont pull the head off just yet, could be other reasons for your symptoms
Julian

And if gases are escaping into the cooling system, would not a static/dynamic pressure test on the cooling system be more revealing?

[triathlondave]

Ive left the cap off, after being a bit obsesive and checking the level all the time. same as you got about 10 miles down the road. But I noticed steam and stopped. put it back on.

No problems.

Though have to say have never needed to put any water in mine ever.

david.

[bikerider]

Forget the sniffer test whatever happened inside the engine when it went bang has broke the cam shaft clean in half -photos to follow. With the help from Northern Bongolow who lives locally, we set about to find route cause of the coolant leak in the first place. this turn out to be perished hose that routes over the starter motor. Air may have made its way into engine block from this hose. The camshaft looks to have picked up due to the scoring marks at bearing No 4 but broke in half at bearing No 3.
Would like to thank Northern bongolow for taking time out and assisting me today.
next job is to remove cylinder head & take it from there.

[dobby]

Sorry to hear that, good luck with the head.

[Bob]

Really sorry to hear of your bad luck, hope it isn't too bad to fix.

[widdowson2008]

Just a thought.............
If the camshaft is broken in the middle, and the rear two sets of valves have not been going up and down as they should, where did they actually stop?
What I'm wondering is if the engine has been cranked with the back two sets of valves motionless, will the two rear pistons have smashed into the stationary valves? or am I missing something?

[mikexgough]

Feel sorry for you having a double whammy of problems....the hose over the starter seems to be one of the most common "weakest" links on the hose side of the system......had to replace mine as I had a pin hole leak in March.....I had noticed a small drop in coolant (well they all do to a degree over time) when I dipped the header tank and then when I did it again a week later it was down again so I investigated....at no time did the running temp rise..... then found it after idling the engine to "bursting" point and it opened up the pinhole.....I wonder how long it had been like that?....
Your camshaft breakage is known to happen with WL-T engines, mainly in hotter climates like Oz and Africa but not unknown in the UK, to a much much lesser degree. Not wishing to create an argument over oils and which is best but the African owners go for a "heavier" oil so it "sticks" on the cam and followers for longer....so in real terms they have upped from 10/30 to 10/40. I hope there is no other damage to you head than the broken camshaft

[321Away]

Spooky, was going to suggest a broken camshaft! i replaced one on monday!! its not a big fix, get on ebay and you'll find new camshafts for about £60, but with the vehicle i worked on it would start but not rev over 1000rpm.

If i were you i'd try refitting a new camshaft before pulling the head off. If you've had valve/piston contact you could be in a heap of trouble,I've seen (still got it actually!) a fully intact piston but the con rod is bent like a banana! You'd have to be extremely unluck for the cam to stop with lobes down, they always seem to slip between, the car i worked on was being driven at speed when the cam snapped, the RAC had it running and so did i before checking the camshaft. So stick a new cam in it, and try doing 2 full rotations by hand, if you can then you've got away with it!

Julian

[mikeonb4c]

Spooky, was going to suggest a broken camshaft! i replaced one on monday!! its not a big fix, get on ebay and you'll find new camshafts for about £60, but with the vehicle i worked on it would start but not rev over 1000rpm.

If i were you i'd try refitting a new camshaft before pulling the head off. If you've had valve/piston contact you could be in a heap of trouble,I've seen (still got it actually!) a fully intact piston but the con rod is bent like a banana! You'd have to be extremely unluck for the cam to stop with lobes down, they always seem to slip between, the car i worked on was being driven at speed when the cam snapped, the RAC had it running and so did i before checking the camshaft. So stick a new cam in it, and try doing 2 full rotations by hand, if you can then you've got away with it!

Julian

Priceless advice

[Northern Bongolow]

to help keep the facts acurate and therefore make the fix easier the problems all appear to lie around cylinder no 3.
the head looks like its got overhot at this point.
the bearing on no 3 has picked up (grabbed) and the cam has snapped at the oil hole at number 2 bearing,it couldnt actually be seen until rotated.

my untrained thoughts are that the head around number 3 has got very hot and/or cracked,this has warped the head,lifting the bearing pedestal slightly out of line with the cam,and its grabbed and snapped.

anyone traced the cam snapping to this kind of failure,i know mister munkey had similar.
like you all rightly say it would be nice if its just a simple cam fault,but the damage to the cam pedestal would probably mean a new head is needed in any case.

any thoughts anyone please.