It does look like after the last trip, the head / gasket has gone 😦
Hooked up to a “virtual compression test” machine…
There’s an induction loop around the (engine) battery’s feed and a clip on the negative…
There’s also an electrical sensor going to one of the coils in the next photo –
And a radiator cap pressure sensor?!
All this lead through a box of tricks via USB to a laptop…
… which shows the results…
Ok, my understanding… You crank the motor and the gizmo detects the current draw needed (by the starter motor) to compress each cylinder, meanwhile at the same split second, the radiator cap sensor is checking for any added pressure in the coolant system, and the gizmo / laptop software puts it all in a pretty graph for you! Amazing… this is why garage’s charge £50 an hour (well mine does) to cover all the equipment they have to have to do all this, and overheads of course…
If I zoom in on the photo of the graph…
You can (apparently) see that the top line is the amount of power needed to compress each cylinder, and the bottom graph shows any pressure in the coolant system, so two cylinders are weaker than the others, and at the same time the coolant pressure goes up… 😦
So either the head has gone (cracked?) or the gasket has gone… 😦
We had a good chat about it today, and the mechanic’s had good successes in the past with a product you pour into the coolant system, let the vehicle run until it’s operating temperature and the thermostat then opens, and you run the engine for a while, then shut it down and let it all cool down overnight, and then run it again the following day, and then he’ll perform the same tests as above to see if it’s better / fixed…
This product is £35 a bottle and sounds like super-“RadWeld” kind of stuff, he’s got one customer who is still running round in a Grand Vitara three years after having this done, so I’m game to give it a go, before shelling out hundreds of pounds to get the head off, skimmed, tested and a new head gasket fitted, and all the labour and messing about this would take… I think it’s worth a go at the end of the day? So the product is on order and will be delivered by one of those little vans that scoot round delivering to all the garages in the area, and added to the coolant system this afternoon, left to do it’s magic overnight, and then retested tomorrow…
JimnyBuggy 