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Was out for a drive today again as it was still sunny, unfortunately the
engine over heated after 30 miles - only for a very short period of time
maybe 30 second before I noticed. Let it cool but it seized up - balls.
Been towed home (not too far luckily) so this weekend will be take the engine to bits again time!
Took the plugs out and it is possible to turn it over so I'm hoping it's not
too bad. Ran fine for 250 miles!
Was out for a drive today again as it was still sunny, unfortunately the
engine over heated after 30 miles - only for a very short period of time
maybe 30 second before I noticed. Let it cool but it seized up - balls.
Been towed home (not too far luckily) so this weekend will be take the engine to bits again time!
Took the plugs out and it is possible to turn it over so I'm hoping it's not
too bad. Ran fine for 250 miles!
At least it still has 4 wheels this time
Thats odd. It normally takes much more than that to seize an engine. Was the oil pressure still OK?
Tested the thermostat before putting it in and it was fine, but maybe it did fail. The water pump did make funny noises when first started but that seemed to clear up quite quickly.
The 2.8 will be making more heat but I've not been pushing anywhere near its limits as it's newly built, was driving mostly tiny country lanes at speeds between 20 and 40mph in 3rd and 4th so nothing too stressful.
Would seem the likely scenario to me - specially as you say it was making a strange noise.
Still odd that the engine should seize in such a short time. Years ago my (then yet to be) wife drove her 850cc Renault 4 from Maidenhead nearly all the way to Swindon with virtually no water before it finally gave up LOL.
Thermostat is fine, water pump seems to be pumping OK, but not pull it out yet (rad is in the way). Oil in the bottom was quite dark but not clumpy. Oil in the top was still quite light.
When you crank the engine on the starter a few seconds the oil pressure goes way way up - I stopped at 6 bar.
So me thinks there's a blockage somewhere. Not pulled the sump off yet, but that's the next step.
When you crank the engine on the starter a few seconds the oil pressure goes way way up - I stopped at 6 bar.
That's very odd. Shouldn't the oil pressure relief valve (in the take off for the oil cooler) prevent excessive oil pressure? I think your diagosis might be correct - you have a blockage somewhere. Did you have any machining done on the block - perhaps there is some swarf in an oilway?
That's very odd. Shouldn't the oil pressure relief valve (in the take off for the oil cooler) prevent excessive oil pressure? I think your diagosis might be correct - you have a blockage somewhere. Did you have any machining done on the block - perhaps there is some swarf in an oilway?
Robin
No machining on the block, only a skim on the head. The oil return will be the first item to check once the sump is off - follow by the main shells.
The oil filter seems heavy (but then its saturated) so I may chop it up see if I can see something in there.
On inspecting the sump it turns out the ring terminal for the earth strap has broken, it was in place so that you could not see it had broken. There was a bit of contact but not much. This is the cause of the high oil pressure. Not much earth gauge OK when you put it on ignition 2, run the starter and it screws that up so the pressure goes up. Disconnect it and no earth = gauge on highest setting.
The also means the starter does not run properly as it doesn't get enough power.
Took the sump off. No obvious marks in any of the bores from the bottom. Push in the oil return and the oil runs out fine, oil pump seems to be OK.
Added a temp earth strap and now the starter runs fine turning the engine over without any problems (no plugs) - no odd sounds from it either.
Hypothesis is airlock (driving up hill), overheat and then unable to run anything due to the earth strap.
Seizing probably due to small tolerances and overheat. Need to pull a cap off check a shell for damage.
Doesn't look as bad now as it did initially. I'm going to do have more of a look around, get a genuine water pump from BMW as the one I have makes a noise and a new sump gasket, new oil and filter and see how it goes.
On inspecting the sump it turns out the ring terminal for the earth strap has broken, it was in place so that you could not see it had broken.
Just out of interest, where is the main earth strap for the engine?
I can't for the life of me remember disconnecting an earthing 'strap' from the engine to the chassis when I took the engine out the donor - the only earthing point on it I can recall is the bundle of brown earths that bolt to the intake manifold under the diagnostic connector bracket.... And that's part of the engine loom. Not what I'd call a strap at all - not like item 14:
You know where the level sender is in the sump (passenger side) there is room there for a 13mm bolt which is the earth On the donor it bolts to the engine mount IIRC.
It is part 14 in that diagram. I've looked at the model year of my donor and found this:
The reason the temp sensor was not working is that the bigger bit at the end that does the sensing had fallen off! Doh.
New sensor from CBS looks a lot better. The switch has an override setting so if the sensor goes you can wind it all the way up and the fan comes on even when the engine is cold.
