I've had a March 89 740 turbo, auto for 5 years, now done 160,000 miles, 100K with me. For a long while the car has run unreliably, the engine cutting out at random. This can happen at any speed from crawling to 60mph, half a mile into journey or 200 miles, and I think it is worse in hot weather. Smells hot and oily when it dies, restarts after between 5 and 20 minutes. Maintained by local Volvo trained mechanic who has done following over 2 yrs:Cleaned breathers and replaced flame trap with full service at 116000. Removed turbo boost regulator, cleaned and refit with new gasket and locking washers at 123000. Exhaust and manifold gasket replaced and broken stud drilled out (very expensively) at 125000. Breathers and distributor cap cleaned out, HT leads and fuel filter replaced with full service at 130000. Cleaned all fuel injection and ignition sensor blocks, connectors and wiring, cleaned and rewired fuel pump feed, cleaned throttle body inner, air mass sensor and engine breathers (again) at 146000. Replaced distributor cap, rotor arm, HT leads, spark plugs, ignition relay, together with missing turbo exhaust nut at 150000. Planned to replace fuel pump relay but astronomical bill for major work on brakes and shockers last month put that on hold. A parts brochure suggests coolant temperature sensor may have failed. Is this a big expense for parts or labour?

Today, towing 3800 lbs of horse and trailer, the car died going slowly up a moderate hill but this time it made a loud whine and blew lots of black smoke out of the exhaust.Happened every time turbo needle hit centre of gauge, even with trailer off. Are these related? Can I safely use car avoiding hills as the car seems ok until turbo is due to kick in? Can't afford new turbo after last big bill. Can I run the car without it?

Thanks for all responses. I rang local main dealer, explained I can't afford their prices but they offered to look at it free (!) and found an inch-wide hole in a hose, which they sealed with insulating tape to keep the car going. Hope replacing the hose (on order) will do the trick. Whether this has contributed to the intermittent cutting out remains to be seen.

Confused about the flame trap. They didn't look at it - fair enough, they weren't charging - but they think my mechanic may have meant a flame guard instead?

Since turbos don't have flame traps, let's hope that this mechanic didn't actually put one in your system! If he did, you are choking off the exhaust gas that is supposed to run your turbo's turbine, which could explain most, if not all, of your symptoms. For more information, go to the top of the BrickBoard site for 'RWD', look near the top of the page for the small BLUE type that says '700-900FAQ' and click on it: you will see a 2-column row of categories, including 'Engines:Turbo'; click on it, and "Go to town." Good Luck! ---PD

Black smoke under boost = vacuum leak (unrelated). See FAQ for details.

There's also a section there re: fuel pump relays.

At first I thought it was an ignition amp/module...common as sin...gets hot and ignition dies. I've had to replace both of them on the 87 and 90 turbos.

But your black smoke note gave me pause...I'd check for a loose compressor bypass valve mount...under boost or engine twist the valve mount opens and bleed compressor air...amm thinks lots of air is going into engine but the air is bled off, thus too much fuel is being pushed into engine=black smoke. Could also be something as simple as a/loose clamps/hoses.

Note...leaking cam seals and lots of hot oil under the hood are fire hazards and deteriorate hoses/belts rapidly. The multiple outlet induction hose on 87+ turbos (before the mitsu integral popoff valve) lists for 189$!!!