UNDER PRESSURE
Dale makes sure that he’s not flogging a dead horse before modifying the engine any further
1997 VOLVO 940 ESTATE
Imagine spending hours of work, and hundreds of pounds, fixing, maintaining and upgrading an engine only to find out that it’s a lemon. This is the thought that popped into my head as I was installing the intercooler that I had just dropped over £300 on. Then panic set in.
Aside from losing a little coolant, which I attribute to a leaking heater hose, I have no real cause to suspect that there is anything wrong with the Volvo’s motor and knowing that these red block engines are notoriously hardy I have been ploughing ahead with a certain degree of tunnel vision. But I needed to put my mind at rest, so I bought a compression tester. These simple, inexpensive little kits can tell you an awful lot about the condition of your piston rings, cylinders and valves, so I set to it.
I removed the HT lead from the coil and pulled the fuel pump fuse because I didn’t need the engine to start, just crank. The next step was to remove the four spark plug leads and plugs. Then it was simply a case of screwing the compression gauge into the first spark plug hole and cranking the engine six or so times to get a stable reading. I then made a note of the numbers before I moved on to the others.
The general consensus is that a healthy engine will have approximately 130psi or more in all cylinders, but more importantly there should be no more than 10 per cent variation between them. I breathed a sigh of relief when my results came back as 140, 146, 142 and 149psi across cylinders one to four. I can now happily plod on, armed with the knowledge that my motor is sound.
I hesitate to use the term ‘peace of mind’ as this is a 24-yearold car with 200,000 miles-plus on the clock and so there will always be a little trepidation. But these test results are encouraging and I’m happy for now.
Let’s see how long that lasts…
All decent numbers for a 200,000 mileplus engine. Result!