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[FONT=Calibri][B]1993 LN130, Generation 2 Hilux Surf, 2.4 diesel manual.[/B][/FONT]
[FONT=Calibri]Yes, a bit of a strange subject line title but I can’t think of a better way to describe the noise.[/FONT]
[FONT=Calibri]This noise can be heard sometimes immediately after cold start up. Similarly, it won’t make the noise at all and thirty minutes into a drive it’ll make it and sound catastrophic, as if something is definitely going to break! The strange thing is that there is no impact on engine performance when it makes the noise; it doesn’t illuminate any warning lights, the engine runs continuously without fault and eventually the noise stops until next time. Steering and braking unaffected.[/FONT]
[FONT=Calibri]Does the noise correlate with the rpm of the engine?– yes and no. So luckily when the battery charging stopped a year or more ago now I replaced the alternator with a brand new one (including the vacuum pump) from Roughtrax because I was convinced that the brushes had disintegrated and that was the noise I was hearing. Strangely it didn’t make the noise for a week or so and then it re-appeared. So put new drive belts on and correctly tensioned them as I thought the excess slap could be catching the fan cowling. Belts running true and quietly now but intermittent noise still there. I also asked for the crankshaft pulley to be checked and inspected as I wondered whether that could be breaking down /coming loose but all was ok.[/FONT]
[FONT=Calibri]Ran the Surf without the air conditioning pump belt connected but intermittent noise still there.[/FONT]
[FONT=Calibri]The speedo now only registers very intermittently and it’s been suggested by a knowledgeable Surf specialist breaker that the cable at the speedo head end becomes detached from its dashboard fixing but continues to be driven from its drive end so is effectively running loose. It’s also been suggested that the turbo turbine could be starting to break down and disintegrate. Admittedly both of these possibilities can be easily inspected and discounted if not the case.[/FONT]
[FONT=Calibri]If I were to say under what driving conditions the noise occurred more than others, then I’d say on overrun, which I guess could be when it’s producing more vacuum than under other conditions but that’s purely guess work.[/FONT]
[FONT=Calibri]If I were to say where the noise seems to be coming from, I'd say offside front, bulkhead / engine area but that's when driving, not with the bonnet up and stationary.[/FONT]
[FONT=Calibri]Has anyone else experienced this? If so can you suggest any other items to inspect or tests to run to diagnose please?
Cheers [/FONT]
[FONT=Calibri]Yes, a bit of a strange subject line title but I can’t think of a better way to describe the noise.[/FONT]
[FONT=Calibri]This noise can be heard sometimes immediately after cold start up. Similarly, it won’t make the noise at all and thirty minutes into a drive it’ll make it and sound catastrophic, as if something is definitely going to break! The strange thing is that there is no impact on engine performance when it makes the noise; it doesn’t illuminate any warning lights, the engine runs continuously without fault and eventually the noise stops until next time. Steering and braking unaffected.[/FONT]
[FONT=Calibri]Does the noise correlate with the rpm of the engine?– yes and no. So luckily when the battery charging stopped a year or more ago now I replaced the alternator with a brand new one (including the vacuum pump) from Roughtrax because I was convinced that the brushes had disintegrated and that was the noise I was hearing. Strangely it didn’t make the noise for a week or so and then it re-appeared. So put new drive belts on and correctly tensioned them as I thought the excess slap could be catching the fan cowling. Belts running true and quietly now but intermittent noise still there. I also asked for the crankshaft pulley to be checked and inspected as I wondered whether that could be breaking down /coming loose but all was ok.[/FONT]
[FONT=Calibri]Ran the Surf without the air conditioning pump belt connected but intermittent noise still there.[/FONT]
[FONT=Calibri]The speedo now only registers very intermittently and it’s been suggested by a knowledgeable Surf specialist breaker that the cable at the speedo head end becomes detached from its dashboard fixing but continues to be driven from its drive end so is effectively running loose. It’s also been suggested that the turbo turbine could be starting to break down and disintegrate. Admittedly both of these possibilities can be easily inspected and discounted if not the case.[/FONT]
[FONT=Calibri]If I were to say under what driving conditions the noise occurred more than others, then I’d say on overrun, which I guess could be when it’s producing more vacuum than under other conditions but that’s purely guess work.[/FONT]
[FONT=Calibri]If I were to say where the noise seems to be coming from, I'd say offside front, bulkhead / engine area but that's when driving, not with the bonnet up and stationary.[/FONT]
[FONT=Calibri]Has anyone else experienced this? If so can you suggest any other items to inspect or tests to run to diagnose please?
Cheers [/FONT]