Duratec, no oil pressure on gauge.

[griffchris]

Evening all.

I have a 420R (Duratec) with dry sump.  I haven't driven the car for a month or so, but all was well last time I did.  I'm in the midst of winter servicing, and today changed the oil and filter.  I thought I'd start the engine following the oil change to get the new oil circulated, it started fine and idled normally, but after a few seconds I noticed the oil pressure gauge was still reading zero.  A quick check revealed plenty of oil coming back into the top of the dry sump tank suggesting oil is circulating normally.  No wires obviously loose.  If I switch the ignition off and on, the needle on the dial flicks around (as do all the other dials) indicating there is power to the gauge.

To complicate matters a little further, I returned to the car a couple of hours later to find the battery flat.  I thought therefore that the gauge issue might have been one of those odd symptoms of a failing battery, but having charged the battery this afternoon (13.8v, 14.2v with alternator running) the oil gauge issue persists.

Am I right in thinking that the oil return to the dry sump tank means the zero oil pressure reading is definitely wrong?  Could this be an earthing issue (that might also explain the battery going flat) or should I be looking for something else?

Thanks very much

Chris 

[anthonym]

If you have a remote (VDO?) pressure device, it is capable of being suspect. They have what amounts to a rhéostat inside which can have issues. (Based on a one hour chat with Stack the other day). And can fail any time or last 20years. 

Anthony

(for Stack Dash owners these have now been replaced with solid state devices, if the device fails the dash displays -99 to indicate .no signal.)

[Paul McKenzie]

Mechanical capillary gauges are much more reliable, and Stack do one.

[griffchris]

Thanks, I have the standard R400/420R non-stack dash, the existing oil pressure sender is this one, If I replace I think I'd rather stick with a standard OEM part: 

https://caterhamparts.co.uk/senders/3896-oil-pressure-sender-including-sub-loom-s3sv-and-csr.html

Before I fork out £85 for a new one:

 - is there a way to confirm whether the existing sender is faulty? - I have a multimeter (but not much knowledge!)

 - How do I fit the new one? - is it just a case of draining the oil, unscrewing the existing one and screwing in the new one?  Do I need any sealant or PTFE tape etc?

Thanks again

Chris

[EEK]

Bit of a conundrum I guess,

As I understand engines, oil pressure is pretty much king. If the engine has been run without oil pressure it is pretty much ******, could be a sleep nessnight so I guess you are hoping/assuming the gauge is at fault.

As we add layers of technology we add layers of potential failure and miss information. As is suggested above a mechanical gauge removes a layer of technology, From other posts the cost is not that dissimilar to a replacement sender. The down side is, if it shows zero the engine is probably ******

 

[SM25T]

Always prefer the reliability of a mechanical OPG .... cheaper than one replacement sender too.

[griffchris]

I appreciate 'flow' and 'pressure' are two different things, but the fact that a 'normal' amount of oil could be seen returning to the top of the dry sump tower has reassurred me!! - there is certainly oil circulating around the engine, but the absence of even a flicker on the dial (other than on switching on the ignition) has made me think the sender is the most likely culprit, I am assuming there would have to be some pressure generated to create the flow I have seen?.

[Jim 123]

Your logic sounds good to me.  Is it possible to disconnect the econoseal connector that joins the sender to the engine loom and check if you can get electrical continuity through the sender to prove it is faulty?

[anthonym]

https://caterhamparts.co.uk/senders/3896-oil-pressure-sender-including-sub-loom-s3sv-and-csr.html

[tomwood]

I agree, your logic sounds good to me. It probably is the sender but would be good to know that before you have to fork out for a replacement.

i replaced mine for a manual OPG a few months back. Pretty sure I still have the sender and pretty sure it’s the same as the one you’ve posted. I’ll take a look tomorrow for you and let you know. You’d be welcome to try it out if I’ve still got it and work out if it’s that or something else.

Tom

[tomwood]

Hi Chris,

I’ve found it and have sent you a PM,

regards

Tom

[griffchris]

Tom

PM received and replied, thanks

Chris

[Geoff Brown]

Depending on the age of your car CC were replacing the oil pressure sender with a different make as the original was 'unreliable'.

When I received my R400d kit in late 2012 there was a note stating that a replacement oil pressure sender was 'in the post' to replace the OE fit sender.

Your sender could be the 'old' type?

[griffchris]

A brief update: I tried Tom's spare oil pressure sender to no avail, so I've decided to trailer it to Kenricks to let them have a look, it needs it's 1st MOT soon anyway so will kill 2 birds with one stone.