We were sitting at a set of traffic lights on Fremont Blvd on our way to an Indian hole-in-the-wall for a Dosa, behind an old Acura Integra and beginning to notice a smell of burning oil. I'm usually over-paranoid and always blame fuel and oil smells on the Opel, much to Jo's amusement, as generally it's someone else. Of course, this time I decided to skip the derision and blame the Integra.
Jo agreed, it had to be the Integra because, as soon as it got further away from us once the light went green, the smell went away. Simple. Bloody cars should be off the road...
Paranoia returned when we got to the restaurant and I sniffed the engine. Yup, burning oil. Crap, and tomorrow was a 100+ mile journey down to Laguna Seca for Jo's driving course.
I couldn't wait to get home and find the problem as I was expecting another weekend of rental cars. Jo couldn't wait to get home either as my conversation was mostly of what could be wrong with the car!
Back home we found the source of the smell - there was a nice brown streak along the bottom of the downpipes. At least it wasn't oil from a cracked gearbox casing from the off-road excursion.
On the topside of the engine I could see the problem, all around the valve cover it was black with oil, and the oil had leaked down the sides and back of the engine, making the bellhousing black too. The other thing I noticed was that the rearmost exhaust manifold bolt was missing, and that might explain some of the vibrations we'd been getting from the engine.
First course of action was to get the valve cover off and replace the gasket, as that must be the problem. I'd had slight leaks off the back of the valve cover ever since we put the 2.4 in back in 2002, but I thought I'd finally fixed that about a year ago... clearly not. I had the front left screw off (the one that holds the spark plug wire router on) and I was pulling off the one behind it when I realised the screw was loose. So was the back one behind that. and the rear one on the other side, and...
Yup, they were all loose, so loose that we had a slow oil leak that had just spread over a period of a few days until we noticed it as it hit the exhaust.
The problem with the 2.4 is that it's a bit of a buzzy engine. We had this one balanced, but I think I'll pay for the 0.1g tolerance next time as we've had a lot of screws loosening up over the 7 years it's been in. I had a case last year where the alternator bracket screws loosened off and the alternator stopped charging due to the poor ground that resulted, and the lost manifold bolt was another example.
Anyway, back with the Manta and I had the screws tightened up and Gunk out pretty quickly. We cleaned it off and dried the car and I've just returned from a long (7-8 mile) trip round the block to see if it's cured, and so far, touch wood, there's no signs of oil. Even if there's a slight leak still, it'll hold for the 200 mile weekend run and I'll replace the gasket on Sunday after the Grand Prix.
The interesting thing is that the slight vestiges of idle hunting has finally gone away. If you remember the last California Column in Manta Magic I was talking about my coil grounding problem, well that mostly fixed the weird idle effect, but lately it was more noticable again, especially returning to idle where it would drop to about 500 rpm before picking up. On the brief test drive that seems to have completely gone now.
I guess that's reasonable. If the valve cover was loose enough to let oil pour out, it was also loose enough to allow air in, and that constitutes an air leak, as that air could get into the intake through the PCV hose. Now the air leak's gone, the random weakening of the mixture would have stopped and the idle could stabilise again.
I wonder if it will stop the car starting on 3 cylinders too?
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment