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Oil light on when hot idling
Posted: 24 Apr 2011, 22:06
by T25rc
Hi guys,
Recently got the van on the road at last (2.0 CU)- so i gave it an oil change to 15-40 mineral. It may be coincidence or that i hadn't noticed it before, but now at hot idle the oil light comes on. No buzzer, just the light - which goes out as soon as you apply any throttle. I guess the light is pressure rather than temperature sensitive - and that it is low pressure since its at idle?
Have i put the wrong oil in, is it getting too hot, or am i getting close to the engine's demise?
Re: Oil light on when hot idling
Posted: 24 Apr 2011, 22:29
by kevtherev
maybe the tick over is a bit slow ?... 900 + or - 50
Re: Oil light on when hot idling
Posted: 25 Apr 2011, 09:28
by Ian Hulley
T25rc wrote: but now at hot idle the oil light comes on. No buzzer, just the light - which goes out as soon as you apply any throttle. I guess the light is pressure rather than temperature sensitive - and that it is low pressure since its at idle?
Have i put the wrong oil in, is it getting too hot, or am i getting close to the engine's demise?
There is no Buzzer of Doom on air cooleds or early wbxers
The switch sounds like it's working perfectly and correctly detecting low pressure.
No idea on oil grade for Aircooled so can't comment.
Possibly getting too hot
Possibly very poorly.
At a guess I'd have to say the oil change is the contributing factor .... check what Aircooled's are supposed to have and replace it.
Ian
Re: Oil light on when hot idling
Posted: 26 Apr 2011, 14:23
by Hacksawbob
Re: Oil light on when hot idling
Posted: 27 Apr 2011, 10:40
by T25rc
Hmm, so i could be looking at a "feck" engine/pump or my 15w-40 is too thin when the engine is hot?
Would putting in the 15w-'50' be thicker? is 50 a more viscous oil than 40 or the other way around?
Re: Oil light on when hot idling
Posted: 27 Apr 2011, 10:57
by Ian Hulley
As I understand it it lubricates to a higher temperature.
Re: Oil light on when hot idling
Posted: 27 Apr 2011, 11:11
by T25rc
I think the numbers refer to the viscosity at cold, and at 100*c - i assume the higher number is more viscous, and due to Aircooled running hot, maybe the 40 is just too thin and i'm losing pressure due to that? I'll change the oil again i guess

Re: Oil light on when hot idling
Posted: 27 Apr 2011, 11:29
by Ian Hulley
It's certainly the easier and cheaper option plus the single common factor in the light starting to flash.
Ian
Re: Oil light on when hot idling
Posted: 27 Apr 2011, 17:03
by kevtherev
If the engine overheats I would be trying to find out why first
Timing
Mixture
Tinware
Flaps
etc
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 13:39
by T25rc
I've been out and bought some 20W-50 oil, is this too thick when cold? I couldn't find any 15w-50 anywhere - basically, will this do?
How do i know if the engine is overheating?
I could do with setting the timing really, it's currently at where it seems happy - not miles advanced as far as i can see (there's a lot of 'swing' left towards advanced). I keep getting the gun hooked up then getting annoyed not being able to find the marks on the crank pulley - what do they look like?
Air leaks all sorted and pipes to dizzy present, working and correct.
Idles fine, not particually lumpy.
Doesn't like running on first starting up, no power to climb a hill for 2ish minutes (maybe the choke is making the mixture too rich?)
How do i go about setting the carb's butterflies as i fear they have probably been messed with, do i use the very small headed screw attached to the linkage on each carb? Or is there a different one i should be using on the carbs body somewhere? It's all very tight with the airbox on, but without it the idle speed gets squewed by not having all vacuums working as they would...
What flaps and tinwear help cool the engine?
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 16:27
by kevtherev
T25rc wrote:I've been out and bought some 20W-50 oil, is this too thick when cold? I couldn't find any 15w-50 anywhere - basically, will this do?
How do i know if the engine is overheating?
I could do with setting the timing really, it's currently at where it seems happy - not miles advanced as far as i can see (there's a lot of 'swing' left towards advanced). I keep getting the gun hooked up then getting annoyed not being able to find the marks on the crank pulley - what do they look like?
Air leaks all sorted and pipes to dizzy present, working and correct.
Idles fine, not particually lumpy.
Doesn't like running on first starting up, no power to climb a hill for 2ish minutes (maybe the choke is making the mixture too rich?)
How do i go about setting the carb's butterflies as i fear they have probably been messed with, do i use the very small headed screw attached to the linkage on each carb? Or is there a different one i should be using on the carbs body somewhere? It's all very tight with the airbox on, but without it the idle speed gets squewed by not having all vacuums working as they would...
What flaps and tinwear help cool the engine?
20w 50 is perfect for summer use
An oil temp gauge is a good addition to your Aircooled engine or a cylinder head temp gauge.
Setting the timing "where it's happy" is not really ideal, so have it done, the marks are indicated in the haynes manual, use tipex to make them stand out, once you know where they are
The lumpyness might even be a weak mixture
Setting the carbs or balancing them is a job for a carb balancer, you can make your own, but there are many types to choose from. for ultimate accuracy with balance and mixture a rolling road is the best way to do it.
the flaps help the engine get up to temperature quicker and when the thermostat works opens them to help cool the engine better.
Having all the tinware and a good seal in place is a must for air cooled engines... they will cook with out it
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 16:50
by Mocki
may i but in here?
many CU engines are missing the timing scale, which is a half moon plastic scale that fits around the fan surround. Without it you will struggle.....
As for over heating, if you can pull the dipstick out and firmly grasp the stick without burning yourself its not over heating. Sounds daft, but if its too hot you wont hold it , never mind grasp it.
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 17:25
by kevtherev
didn't know about the scale Steve
The post reads like it's not there.
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 18:22
by T25rc
Cheers,
I'll get this 20w50 in and go from there then - Is it not ok for our relatively mild winters?
Timing wise, you're right - i know it needs doing. The scale is on the block fine, with numbers - it's just the 'notch' is very very hard to spot (i've not been able to see it rocking the car with a full revolution on the pulley) and my haynes isn't much help on what it looks like. Is it viable to turn the engine over to get the rotor arm pointing at cyl 1 and then search on the pulley? Makes sense...
I have a timing gun that you can set the advance with a delay - so for that, i need to set the gun to 4-6deg and then get the notch lined up with '0' on the scale...? Is this with all vac pipes connected? Another problem is that i have no idea of idle speed - do i adjust this with the small screws i mentioned earlier, again i can only go to 'where it's happy'
Thanks again
Re: Oil light on when hot idling
Posted: 28 Apr 2011, 18:34
by jason k
as said,
ensure engine bay seal is all there
ensure tinware complete
mixture
timing
the tip re grabbing the dipstick is bang on.
these motors are basic but not many people can set the carbs up well.
if your not too far from chester i would go to see steve shaw who is a genius with solex carbs
http://www.gasure.co.uk" onclick="window.open(this.href);return false;