Fixed auxiliary cooling fan, stops cold startup topend rattle!
10-02-2002, 03:14 PM
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Fixed auxiliary cooling fan, stops cold startup topend rattle!
Much to my surprise following the fixing of the auxiliary engine cooling fan (which has never worked on my car with the ignition off), my engine no longer rattles for a few seconds from a cold start up having been left for 24 hrs or so.
Could it be that excessive heat build up caused by a faulty fan, could lead to oil in the rockers draining away causing top end rattle at start up?
I was certainly surprised how long the fan can run for after turning the engine off. For 10 or 15 minute stints sometimes when very hot.
I have also noticed that the car idles at about 1100 rpm more than usually. Is this to recoup some of the lost charge in the battery?
Rocket
P.S By the way the fix for the fan was a relay at the front of the car being faulty, not the temperature sensor or resister. I believe the relay is supposed to provide only a low power feed to the fan with the ignition removed to stop the battery being draining by running at high speed.
Could it be that excessive heat build up caused by a faulty fan, could lead to oil in the rockers draining away causing top end rattle at start up?
I was certainly surprised how long the fan can run for after turning the engine off. For 10 or 15 minute stints sometimes when very hot.
I have also noticed that the car idles at about 1100 rpm more than usually. Is this to recoup some of the lost charge in the battery?
Rocket
P.S By the way the fix for the fan was a relay at the front of the car being faulty, not the temperature sensor or resister. I believe the relay is supposed to provide only a low power feed to the fan with the ignition removed to stop the battery being draining by running at high speed.
10-02-2002, 05:53 PM
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Hi Rocket,
FWIW, are you sure the faulty relay wasn't in the engine compartment fuse panel? That's where the rear blower's relay is. I can't think of anything in the front end of the car (other than the CCU) that impacts the rear blower's operation.
The rear blower relay works something like this:
-The CCU determines which speed the blower runs at. It connects terminal #6 to ground for slow-speed operation, terminal #1 to ground for fast-speed.
-In both cases, connecting the terminal to ground allows current to flow through one of the relay's two internal coils (one for slow, one for fast).
-Each internal coil/relay controls a switch--either slow or fast-speed.
-Slow and fast-speed (or stage 1 and stage 2) both get their power from the same source (the terminals on the relay plug are shorted together). For slow-speed operation, the power is directed through a ballast resistor downstream of the relay. Running the power through the resistor creates a voltage drop, causing the blower to run slower.
Well ... anyway .... glad to hear your blower is fixed!
FWIW, are you sure the faulty relay wasn't in the engine compartment fuse panel? That's where the rear blower's relay is. I can't think of anything in the front end of the car (other than the CCU) that impacts the rear blower's operation.
The rear blower relay works something like this:
-The CCU determines which speed the blower runs at. It connects terminal #6 to ground for slow-speed operation, terminal #1 to ground for fast-speed.
-In both cases, connecting the terminal to ground allows current to flow through one of the relay's two internal coils (one for slow, one for fast).
-Each internal coil/relay controls a switch--either slow or fast-speed.
-Slow and fast-speed (or stage 1 and stage 2) both get their power from the same source (the terminals on the relay plug are shorted together). For slow-speed operation, the power is directed through a ballast resistor downstream of the relay. Running the power through the resistor creates a voltage drop, causing the blower to run slower.
Well ... anyway .... glad to hear your blower is fixed!
10-03-2002, 12:59 AM
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speaking of a (top-end) rattle at start-up. How many of you get this when the car is first started after sitting over night?
I get a rattle for about 2 seconds until (I believe) the rockers pump up.
How reliable are these hydraulic rockers?
There had been talk of converting back to mechanicals and a noted power/torque increase. Has anyone done this?
Thanks
Chris
I get a rattle for about 2 seconds until (I believe) the rockers pump up.
How reliable are these hydraulic rockers?
There had been talk of converting back to mechanicals and a noted power/torque increase. Has anyone done this?
Thanks
Chris
10-03-2002, 08:46 PM
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Hey Rocket,
One more thought. Does your car always idle at close to 1100 RPM, or only some of the time? My idle has been high at about 1050 RPM for nearly a year now. But, it never drops below this level to a normal idle speed.
One more thought. Does your car always idle at close to 1100 RPM, or only some of the time? My idle has been high at about 1050 RPM for nearly a year now. But, it never drops below this level to a normal idle speed.
10-04-2002, 11:58 AM
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Hi Randall,
Normally the engine idles fine at about 800/900 rpm. I read in the manual that the revs can, under certain circumstances, increase with the extra electrical load (fans I assume) while using the A/C hence my comments about this happening when the auxillary fan has been on for a while.
The idle returns to normal eventually, and does so as if the ECU has just switched the speed because there will be a sudden drop in revs. I notice this particularly as my exhaust makes about 100db at tickover, and the increase in noise between 800 and 1100 rpm is quite noticeable.
Rocket
P.S Incidentially you are probably correct about the location of the relay. Its just that it was replaced under warranty so I have no receipt for the part in question, and it was the service desk person, not the actual mechanic who gave me the explanation.
Normally the engine idles fine at about 800/900 rpm. I read in the manual that the revs can, under certain circumstances, increase with the extra electrical load (fans I assume) while using the A/C hence my comments about this happening when the auxillary fan has been on for a while.
The idle returns to normal eventually, and does so as if the ECU has just switched the speed because there will be a sudden drop in revs. I notice this particularly as my exhaust makes about 100db at tickover, and the increase in noise between 800 and 1100 rpm is quite noticeable.
Rocket
P.S Incidentially you are probably correct about the location of the relay. Its just that it was replaced under warranty so I have no receipt for the part in question, and it was the service desk person, not the actual mechanic who gave me the explanation.
