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Nova_Tek
09-03-12, 08:19 PM
Evening all,

The Cav got it's MOT yesterday and passed fine. Whilst it was at the test centre and up in the air, I realised that the oil pressure sender was still in place but the wire had snapped. So today with some free time I set about sorting it out seeing as the volt/oil gauges were already in.

At first, I realised that the oil pressure warning light wouldn't come on when ignition was switched on. I found the broken gauge wire and sorted it out then plugged it into the empty connector on the sender and checked the dash wire was ok. Ignition on and gauge was at 0 (how it should be). Started it up and the gauge jumped to 3 bar. Hmmm... Maybe because the car had been driven a fair bit today and engine was still very warm the oil pressure is sitting lower (which again is what normally happens) but a dab of throttle should see the gauge go up but in this case it would only budge 1/2 a bar at most.

So I thought maybe the wires are the wrong way round. Swapped the wires over at the sender, ignition on, dash oil light on, oil gauge off the scale! Started it up and the light dims to half and stays on. Clearly the wrong way round. Swap the wires back to how they were and it goes back to how it was - no dash light, gauge works but only shows 3 bar at all times.

I gave it a good few hours for the engine to cool right down and just started it. Gauge again jumps to 3 bar (from experience it should jump to between 4 - 5 bar from cold start up). Give it some throttle and at around 3k the gauge goes up to between 3.5 - 4 bar.

Yes the engine has been stood for a while but it starts and runs first time, no misfire, rad fan comes on, performs well, no tappet noise, no bottom end knock or rattle. The mechanic which fitted the engine last year even commented that it sounds like a healthy engine and we had found a "good'un". Looking to drop the oil out and give it fresh oil and filter sometime next week.

So what can this mean... any ideas? Faulty sender (seeing as light never comes on)?

BTW - engine is 20SEH

Nova_Tek
10-03-12, 09:26 AM
Yeah I know, its a bit of a long post but no one got any ideas?

pie
10-03-12, 09:29 AM
when mines driven its read 4 to 4.5 come to lights clutch in and then reads 2

Nova_Tek
10-03-12, 10:51 PM
Yeah thats how it should be and how the SR, my old 1.2 and the XEV behave. Once warmed up the pressure was at 1.5 bar which is normal according to Haynes but when at 2 - 3k revs it should be 4+. This one hits ~3.5 bar and bounces off to 3. Me thinks the relief valve is a bit dodge.

Monday I will be dropping out the oil and flushing it with el-cheapo ASDA semi-syn, dropping that out and filling it with proper stuff. May even remove the relief valve and swapping it with a spare nylon one I've got.

Nova_Tek
13-03-12, 06:55 PM
Sorted it. It must've been the oil. Ran the engine until it got to the stage the fan comes on, drained old oil and removed filter. Added Supermarket oil and new filter. Ran engine at fast idle until fan came on (note that when the new oil went in the oil pressure light on the dash started working whereas before it wasn't).

Drained the supermarket oil, which had picked up some more dirty, gunky sh*t. Changed filter again and added proper quality oil.

Pressure is now at 4.5 bar when started from cold, drops to 2 bar when engine is hot and tops out at 4 - 4.5 bar when revs pick up. How it should be!

pie
13-03-12, 07:04 PM
happy days dude :)

Nova_Tek
13-03-12, 07:23 PM
Yep, a big sigh of relief. I was starting to think the worst.

pie
13-03-12, 07:26 PM
lol all good tho buddy

Nova_Tek
13-03-12, 07:30 PM
Yep. All it needs is the down pipe to mid box seas, springs and bolts to be changed to stop the blow and the washer jet system to be un-blocked and it'll be done.

pie
13-03-12, 07:40 PM
sweet dude :)

Nova_Tek
13-03-12, 07:49 PM
Will be updating the thread when I get finalised pics and give it a good going over with some autoglym :d