89 740 possible turbo fail?
#1
06-18-2018, 04:22 PM
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89 740 possible turbo fail?
So I recently got an 89 Volvo 740 turbo with about 194k miles on it. It has been running just fine but about a week ago I was driving on the highway and switched to a/c to cool off and I heard a whine from my engine. Now whenever the turbo starts to engage (when the needle on the dash goes into the colored turbo section) the turbo won’t seem to engage and my car won’t accelerate or maintain highway speeds. It still runs and can drive at low speeds. The air mass sensor is clean on both ends. The air hose from the inter cooler to turbo is clean but appears to be collecting grease on the underside from somewhere. That’s all I’ve done so far to troubleshoot the issue. Is my turbo dead or is there something I can do?
#2
06-18-2018, 06:11 PM
#3
06-19-2018, 03:27 PM
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make sure the high pressure hose coming out of the turbo to the intercooler isn't blowing a leak under positive boost. I had that problem with my 92, the silicone hose was mushy, and wasn't staying under the clamp.. drove fine without boost, but when it was boosted, lost all power.
#4
06-19-2018, 03:39 PM
if the 'pressure is releasing', it has to be going somewhere. if it only fails under positive boost, it could well be a nearly invisible crack that gets opened up under boost pressure, but is normally closed. I'd check the whole air path from the turbo through the intercooler to the throttle body... check the intercooler itself. check the idle air hoses, and other larger diameter vacuum hoses...
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06-19-2018, 03:54 PM
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