Ha ha. I have done 2 Rover 200 hgs in the past, one for my younger sister and one for my younger brother when his cambelt snapped and bent all the valves. Good days then, the local scrappie sold us a complete head for £30! I know the sound you describe! All cars are a bit scary when you start them up after that level of work. Any oil etc that got spilt on to the exhaust smokes off and makes you think something is about to go up in flames and I am usually expecting the engine to split out a forgotten socket or something, but this one was actually good!
I think I found the problem today. A split expansion tank. With all covers removed and everything dry I was filling up very slowly and carefully with a garden hose. Then I noticed a drip running down the side of the expansion tank and thought how on earth did I manage that when I was trying so carefully to keep everything dry? I tried to wipe it dry but it just wouldn't .
A few minutes later and the expansion tank was removed. It looked to have a light 2 inch scratch on the side but this actually was a dripping split. If it was dripping like this with 0 pressure what would it be doing under a lot of pressure? I have read about these splitting in a few places on line but I wouldn't have believed it until I saw it.
So I get a new tank next week from the local BMW dealers and then I will know one of the following:-
1) this was the original problem. It caused a loss of coolant and a subsequent overheat and hg failure, or
2) the head gasket went on the original owner for some other reason that I haven't found yet and the cylinder compression then found its way into the coolant and caused the expansion tank to crack. If there was that much pressure wouldn't the cap allow an overflow first?
3) I haven't done a good enough job and I have created my own version of number 2.
Given the lovely way the car runs, I am putting my money on number 1. Surely something must have caused the original failure and as yet I haven't found anything else.
Assuming this ends up good the car will be great because all the injector O rings, VANOS seals etc were tired and are now new as are the valve seals, the plugs, the water pump, the thermostat housing and thermostat, serpentine belts etc etc
I am embarrassed to total up the hours I have spent on this. I bet 40 or even more, but I am a Chartered Accountant turned property developer, not a car mechanic and I am working in a cramped little garage without special tools. Tbh it took me a few hours to remove the inlet manifold first time around. This morning I wanted to check on a couple of coolant pipe O rings and put a jubilee clip on a breather hose under the manifold and I was able to have the manifold removed, the jobs done and the manifold back on within the hour so there is a definite learning curve.
I was originally scared of taking off the VANOS and camshaft chains but having done this, thanks to the amazing information online, I can say it it is a doddle. I cut some old piping to put in the primary chain tensioner and some more to hold the exhaust side piston of the VANOS solid to set the camshaft sprockets and if this hasn't worked and the car should drive even better I would be surprised. I found measurements of the VANOS tool on line and this to me seemed to replicate the VANOS unit in this position. I would love the correct tools but this has cost enough as a one off project without them. I have spent about £700 in total.
I am now looking for another BMW 2.5 with a head gasket failure to sort to take advantage of this new found skill! :lol:
